Buggy rhashtable walking

Buggy rhashtable walking

[Herbert Xu]

Hi:

While working on rhashtable I noticed that wireless is walking
rhashtables by hand using rht_for_each_*.  You must not do that
as an rhashtable can entail multiple hash tables when resizing.
If you walk it by hand then you may end up missing entries.

The correct way to do it is to use the rhashtable walk interface.
However, even this comes with the caveat that a given entry may
show up multiple times.  So if you cannot handle that then you
must construct your own data structure outside of rhashtable, like
we do in IPsec.

So the question is can wireless handle seeing an entry multiple
times? In particular, __ieee80211_rx_handle_packet would appear
to process the same packet multiple times if this were to happen.

Cheers,
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

Buggy rhashtable walking

[Herbert Xu]

Hi:

While working on rhashtable I noticed that wireless is walking
rhashtables by hand using rht_for_each_*.  You must not do that
as an rhashtable can entail multiple hash tables when resizing.
If you walk it by hand then you may end up missing entries.

The correct way to do it is to use the rhashtable walk interface.
However, even this comes with the caveat that a given entry may
show up multiple times.  So if you cannot handle that then you
must construct your own data structure outside of rhashtable, like
we do in IPsec.

So the question is can wireless handle seeing an entry multiple
times? In particular, __ieee80211_rx_handle_packet would appear
to process the same packet multiple times if this were to happen.

Cheers,
-- 
Email: Herbert Xu <herbert-lOAM2aK0SrRLBo1qDEOMRrpzq4S04n8Q@public.gmane.org>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
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Re: Buggy rhashtable walking

[Herbert Xu]

On Thu, Aug 04, 2016 at 03:18:46PM +0800, Herbert Xu wrote:
> 
> So the question is can wireless handle seeing an entry multiple
> times? In particular, __ieee80211_rx_handle_packet would appear
> to process the same packet multiple times if this were to happen.

It's worse than I thought.  In fact it's not walking the table
at all, rather it's doing a hash lookup by hand!

This cannot possibly work given that rhashtable makes use of
multiple hash tables.

In fact this also demonstrates why putting multiple identical
objects into the same table is crap.  Because there is no sane
way of returning all objects corresponding to a single key, given
that they may be spread over multiple tables.

So I'm going to fix this by consolidating identical objects into
a single rhashtable entry which also lets us get rid of the
insecure_elasticity setting.

So the next time someone comes along and wants to add multiple
objects with the same key to one table, please just say no.

Thanks,
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

Re: Buggy rhashtable walking

[Herbert Xu]

On Thu, Aug 04, 2016 at 03:18:46PM +0800, Herbert Xu wrote:
> 
> So the question is can wireless handle seeing an entry multiple
> times? In particular, __ieee80211_rx_handle_packet would appear
> to process the same packet multiple times if this were to happen.

It's worse than I thought.  In fact it's not walking the table
at all, rather it's doing a hash lookup by hand!

This cannot possibly work given that rhashtable makes use of
multiple hash tables.

In fact this also demonstrates why putting multiple identical
objects into the same table is crap.  Because there is no sane
way of returning all objects corresponding to a single key, given
that they may be spread over multiple tables.

So I'm going to fix this by consolidating identical objects into
a single rhashtable entry which also lets us get rid of the
insecure_elasticity setting.

So the next time someone comes along and wants to add multiple
objects with the same key to one table, please just say no.

Thanks,
-- 
Email: Herbert Xu <herbert-lOAM2aK0SrRLBo1qDEOMRrpzq4S04n8Q@public.gmane.org>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
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Re: Buggy rhashtable walking

[Johannes Berg]

> So I'm going to fix this by consolidating identical objects into
> a single rhashtable entry which also lets us get rid of the
> insecure_elasticity setting.

Hm. Would you rather allocate a separate head entry for the hashtable,
or chain the entries?

(Luckily) the colliding key case practically never happens, and some
drivers don't even allow it, so that's perhaps something to keep in
mind for this. Perhaps we should just generally disallow it - but a few
people (hi Ben) would be really unhappy about that I guess.

I think this might affect more than one use of rhashtable in mac80211
now, since the mesh paths also use it.

johannes

Re: Buggy rhashtable walking

[Herbert Xu]

On Fri, Aug 05, 2016 at 08:16:53AM +0200, Johannes Berg wrote:
> 
> Hm. Would you rather allocate a separate head entry for the hashtable,
> or chain the entries?

My plan is to build support for this directly into rhashtable.
So I'm adding a struct rhlist_head that would be used in place
of rhash_head for these cases and it'll carry an extra pointer
for the list of identical entries.

I will then add an additional layer of insert/lookup interfaces
for rhlist_head.

So bottom-line is that if you have no identical entries that you
only incur an extra 8 bytes per-object.

Cheers,
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

Re: Buggy rhashtable walking

[Herbert Xu]

On Fri, Aug 05, 2016 at 08:16:53AM +0200, Johannes Berg wrote:
> 
> Hm. Would you rather allocate a separate head entry for the hashtable,
> or chain the entries?

My plan is to build support for this directly into rhashtable.
So I'm adding a struct rhlist_head that would be used in place
of rhash_head for these cases and it'll carry an extra pointer
for the list of identical entries.

I will then add an additional layer of insert/lookup interfaces
for rhlist_head.

So bottom-line is that if you have no identical entries that you
only incur an extra 8 bytes per-object.

Cheers,
-- 
Email: Herbert Xu <herbert-lOAM2aK0SrRLBo1qDEOMRrpzq4S04n8Q@public.gmane.org>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
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Re: Buggy rhashtable walking

[Johannes Berg]

On Fri, 2016-08-05 at 18:48 +0800, Herbert Xu wrote:
> On Fri, Aug 05, 2016 at 08:16:53AM +0200, Johannes Berg wrote:
> > 
> > Hm. Would you rather allocate a separate head entry for the
> > hashtable,
> > or chain the entries?
> 
> My plan is to build support for this directly into rhashtable.
> So I'm adding a struct rhlist_head that would be used in place
> of rhash_head for these cases and it'll carry an extra pointer
> for the list of identical entries.
> 
> I will then add an additional layer of insert/lookup interfaces
> for rhlist_head.

Oh, ok.

> So bottom-line is that if you have no identical entries that you
> only incur an extra 8 bytes per-object.
> 
Right.

Thanks!

johannes

Re: Buggy rhashtable walking

[Ben Greear]

On 08/05/2016 03:50 AM, Johannes Berg wrote:
> On Fri, 2016-08-05 at 18:48 +0800, Herbert Xu wrote:
>> On Fri, Aug 05, 2016 at 08:16:53AM +0200, Johannes Berg wrote:
>>>
>>> Hm. Would you rather allocate a separate head entry for the
>>> hashtable,
>>> or chain the entries?
>>
>> My plan is to build support for this directly into rhashtable.
>> So I'm adding a struct rhlist_head that would be used in place
>> of rhash_head for these cases and it'll carry an extra pointer
>> for the list of identical entries.
>>
>> I will then add an additional layer of insert/lookup interfaces
>> for rhlist_head.

Herbert, thank you for fixing this!

It would not be fun to have to revert to the old way of hashing
stations in mac80211...

I'll be happy to test the patches when you have them ready.

Ben


-- 
Ben Greear <greearb@candelatech.com>
Candela Technologies Inc  http://www.candelatech.com

Re: Buggy rhashtable walking

[Herbert Xu]

On Fri, Aug 05, 2016 at 04:46:43AM -0700, Ben Greear wrote:
>
> It would not be fun to have to revert to the old way of hashing
> stations in mac80211...
> 
> I'll be happy to test the patches when you have them ready.

Thanks for the offer.  Unfortunately it'll be a few days before
I'm ready because I need to work through some crypto patches first.

Cheers,
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

Re: Buggy rhashtable walking

[Herbert Xu]

On Fri, Aug 05, 2016 at 04:46:43AM -0700, Ben Greear wrote:
>
> It would not be fun to have to revert to the old way of hashing
> stations in mac80211...
> 
> I'll be happy to test the patches when you have them ready.

Thanks for the offer.  Unfortunately it'll be a few days before
I'm ready because I need to work through some crypto patches first.

Cheers,
-- 
Email: Herbert Xu <herbert-lOAM2aK0SrRLBo1qDEOMRrpzq4S04n8Q@public.gmane.org>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
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[PATCH 0/2] rhashtable: rhashtable with duplicate objects

[Herbert Xu]

On Fri, Aug 05, 2016 at 12:50:33PM +0200, Johannes Berg wrote:
> > My plan is to build support for this directly into rhashtable.
> > So I'm adding a struct rhlist_head that would be used in place
> > of rhash_head for these cases and it'll carry an extra pointer
> > for the list of identical entries.
> > 
> > I will then add an additional layer of insert/lookup interfaces
> > for rhlist_head.
> 
> Oh, ok.

OK, it's finally ready now.

This series contains one two patches.  The first adds the rhlist
interface and the second converts mac80211 to use it.  If this works
out I'll then proceed to convert the other insecure_elasticity
users over to this.

I've tested the rhlist code with test_rhashtable but I haven't
tested the mac80211 conversion.  So please give it a go and see
if it still works.

Thanks!
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

[PATCH 0/2] rhashtable: rhashtable with duplicate objects

[Herbert Xu]

On Fri, Aug 05, 2016 at 12:50:33PM +0200, Johannes Berg wrote:
> > My plan is to build support for this directly into rhashtable.
> > So I'm adding a struct rhlist_head that would be used in place
> > of rhash_head for these cases and it'll carry an extra pointer
> > for the list of identical entries.
> > 
> > I will then add an additional layer of insert/lookup interfaces
> > for rhlist_head.
> 
> Oh, ok.

OK, it's finally ready now.

This series contains one two patches.  The first adds the rhlist
interface and the second converts mac80211 to use it.  If this works
out I'll then proceed to convert the other insecure_elasticity
users over to this.

I've tested the rhlist code with test_rhashtable but I haven't
tested the mac80211 conversion.  So please give it a go and see
if it still works.

Thanks!
-- 
Email: Herbert Xu <herbert-lOAM2aK0SrRLBo1qDEOMRrpzq4S04n8Q@public.gmane.org>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

[PATCH 1/2] rhashtable: Add rhlist interface

[Herbert Xu]

The insecure_elasticity setting is an ugly wart brought out by
users who need to insert duplicate objects (that is, distinct
objects with identical keys) into the same table.

In fact, those users have a much bigger problem.  Once those
duplicate objects are inserted, they don't have an interface to
find them (unless you count the walker interface which walks
over the entire table).

Some users have resorted to doing a manual walk over the hash
table which is of course broken because they don't handle the
potential existence of multiple hash tables.  The result is that
they will break sporadically when they encounter a hash table
resize/rehash.

This patch provides a way out for those users, at the expense
of an extra pointer per object.  Essentially each object is now
a list of objects carrying the same key.  The hash table will
only see the lists so nothing changes as far as rhashtable is
concerned.

To use this new interface, you need to insert a struct rhlist_head
into your objects instead of struct rhash_head.  While the hash
table is unchanged, for type-safety you'll need to use struct
rhltable instead of struct rhashtable.  All the existing interfaces
have been duplicated for rhlist, including the hash table walker.

One missing feature is nulls marking because AFAIK the only potential
user of it does not need duplicate objects.  Should anyone need
this it shouldn't be too hard to add.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
---

 include/linux/rhashtable.h |  490 ++++++++++++++++++++++++++++++++++-----------
 lib/rhashtable.c           |  231 ++++++++++++++++-----
 2 files changed, 560 insertions(+), 161 deletions(-)

diff --git a/include/linux/rhashtable.h b/include/linux/rhashtable.h
index fd82584..dc7bea6 100644
--- a/include/linux/rhashtable.h
+++ b/include/linux/rhashtable.h
@@ -1,7 +1,7 @@
 /*
  * Resizable, Scalable, Concurrent Hash Table
  *
- * Copyright (c) 2015 Herbert Xu <herbert@gondor.apana.org.au>
+ * Copyright (c) 2015-2016 Herbert Xu <herbert@gondor.apana.org.au>
  * Copyright (c) 2014-2015 Thomas Graf <tgraf@suug.ch>
  * Copyright (c) 2008-2014 Patrick McHardy <kaber@trash.net>
  *
@@ -53,6 +53,11 @@ struct rhash_head {
 	struct rhash_head __rcu		*next;
 };
 
+struct rhlist_head {
+	struct rhash_head		rhead;
+	struct rhlist_head __rcu	*next;
+};
+
 /**
  * struct bucket_table - Table of hash buckets
  * @size: Number of hash buckets
@@ -137,6 +142,7 @@ struct rhashtable_params {
  * @key_len: Key length for hashfn
  * @elasticity: Maximum chain length before rehash
  * @p: Configuration parameters
+ * @rhlist: True if this is an rhltable
  * @run_work: Deferred worker to expand/shrink asynchronously
  * @mutex: Mutex to protect current/future table swapping
  * @lock: Spin lock to protect walker list
@@ -147,12 +153,21 @@ struct rhashtable {
 	unsigned int			key_len;
 	unsigned int			elasticity;
 	struct rhashtable_params	p;
+	bool				rhlist;
 	struct work_struct		run_work;
 	struct mutex                    mutex;
 	spinlock_t			lock;
 };
 
 /**
+ * struct rhltable - Hash table with duplicate objects in a list
+ * @ht: Underlying rhtable
+ */
+struct rhltable {
+	struct rhashtable ht;
+};
+
+/**
  * struct rhashtable_walker - Hash table walker
  * @list: List entry on list of walkers
  * @tbl: The table that we were walking over
@@ -163,9 +178,10 @@ struct rhashtable_walker {
 };
 
 /**
- * struct rhashtable_iter - Hash table iterator, fits into netlink cb
+ * struct rhashtable_iter - Hash table iterator
  * @ht: Table to iterate through
  * @p: Current pointer
+ * @list: Current hash list pointer
  * @walker: Associated rhashtable walker
  * @slot: Current slot
  * @skip: Number of entries to skip in slot
@@ -173,6 +189,7 @@ struct rhashtable_walker {
 struct rhashtable_iter {
 	struct rhashtable *ht;
 	struct rhash_head *p;
+	struct rhlist_head *list;
 	struct rhashtable_walker walker;
 	unsigned int slot;
 	unsigned int skip;
@@ -339,13 +356,11 @@ static inline int lockdep_rht_bucket_is_held(const struct bucket_table *tbl,
 
 int rhashtable_init(struct rhashtable *ht,
 		    const struct rhashtable_params *params);
+int rhltable_init(struct rhltable *hlt,
+		  const struct rhashtable_params *params);
 
-struct bucket_table *rhashtable_insert_slow(struct rhashtable *ht,
-					    const void *key,
-					    struct rhash_head *obj,
-					    struct bucket_table *old_tbl,
-					    void **data);
-int rhashtable_insert_rehash(struct rhashtable *ht, struct bucket_table *tbl);
+void *rhashtable_insert_slow(struct rhashtable *ht, const void *key,
+			     struct rhash_head *obj);
 
 void rhashtable_walk_enter(struct rhashtable *ht,
 			   struct rhashtable_iter *iter);
@@ -507,6 +522,31 @@ void rhashtable_destroy(struct rhashtable *ht);
 	rht_for_each_entry_rcu_continue(tpos, pos, (tbl)->buckets[hash],\
 					tbl, hash, member)
 
+/**
+ * rhl_for_each_rcu - iterate over rcu hash table list
+ * @pos:	the &struct rlist_head to use as a loop cursor.
+ * @list:	the head of the list
+ *
+ * This hash chain list-traversal primitive should be used on the
+ * list returned by rhltable_lookup.
+ */
+#define rhl_for_each_rcu(pos, list)					\
+	for (pos = list; pos; pos = rcu_dereference_raw(pos->next))
+
+/**
+ * rhl_for_each_entry_rcu - iterate over rcu hash table list of given type
+ * @tpos:	the type * to use as a loop cursor.
+ * @pos:	the &struct rlist_head to use as a loop cursor.
+ * @list:	the head of the list
+ * @member:	name of the &struct rlist_head within the hashable struct.
+ *
+ * This hash chain list-traversal primitive should be used on the
+ * list returned by rhltable_lookup.
+ */
+#define rhl_for_each_entry_rcu(tpos, pos, list, member)			\
+	for (pos = list; pos && rht_entry(tpos, pos, member);		\
+	     pos = rcu_dereference_raw(pos->next))
+
 static inline int rhashtable_compare(struct rhashtable_compare_arg *arg,
 				     const void *obj)
 {
@@ -516,18 +556,8 @@ static inline int rhashtable_compare(struct rhashtable_compare_arg *arg,
 	return memcmp(ptr + ht->p.key_offset, arg->key, ht->p.key_len);
 }
 
-/**
- * rhashtable_lookup_fast - search hash table, inlined version
- * @ht:		hash table
- * @key:	the pointer to the key
- * @params:	hash table parameters
- *
- * Computes the hash value for the key and traverses the bucket chain looking
- * for a entry with an identical key. The first matching entry is returned.
- *
- * Returns the first entry on which the compare function returned true.
- */
-static inline void *rhashtable_lookup_fast(
+/* Internal function, do not use. */
+static inline struct rhash_head *__rhashtable_lookup(
 	struct rhashtable *ht, const void *key,
 	const struct rhashtable_params params)
 {
@@ -539,8 +569,6 @@ static inline void *rhashtable_lookup_fast(
 	struct rhash_head *he;
 	unsigned int hash;
 
-	rcu_read_lock();
-
 	tbl = rht_dereference_rcu(ht->tbl, ht);
 restart:
 	hash = rht_key_hashfn(ht, tbl, key, params);
@@ -549,8 +577,7 @@ restart:
 		    params.obj_cmpfn(&arg, rht_obj(ht, he)) :
 		    rhashtable_compare(&arg, rht_obj(ht, he)))
 			continue;
-		rcu_read_unlock();
-		return rht_obj(ht, he);
+		return he;
 	}
 
 	/* Ensure we see any new tables. */
@@ -559,96 +586,165 @@ restart:
 	tbl = rht_dereference_rcu(tbl->future_tbl, ht);
 	if (unlikely(tbl))
 		goto restart;
-	rcu_read_unlock();
 
 	return NULL;
 }
 
+/**
+ * rhashtable_lookup - search hash table
+ * @ht:		hash table
+ * @key:	the pointer to the key
+ * @params:	hash table parameters
+ *
+ * Computes the hash value for the key and traverses the bucket chain looking
+ * for a entry with an identical key. The first matching entry is returned.
+ *
+ * This must only be called under the RCU read lock.
+ *
+ * Returns the first entry on which the compare function returned true.
+ */
+static inline void *rhashtable_lookup(
+	struct rhashtable *ht, const void *key,
+	const struct rhashtable_params params)
+{
+	struct rhash_head *he = __rhashtable_lookup(ht, key, params);
+
+	return he ? rht_obj(ht, he) : NULL;
+}
+
+/**
+ * rhashtable_lookup_fast - search hash table, without RCU read lock
+ * @ht:		hash table
+ * @key:	the pointer to the key
+ * @params:	hash table parameters
+ *
+ * Computes the hash value for the key and traverses the bucket chain looking
+ * for a entry with an identical key. The first matching entry is returned.
+ *
+ * Only use this function when you have other mechanisms guaranteeing
+ * that the object won't go away after the RCU read lock is released.
+ *
+ * Returns the first entry on which the compare function returned true.
+ */
+static inline void *rhashtable_lookup_fast(
+	struct rhashtable *ht, const void *key,
+	const struct rhashtable_params params)
+{
+	void *obj;
+
+	rcu_read_lock();
+	obj = rhashtable_lookup(ht, key, params);
+	rcu_read_unlock();
+
+	return obj;
+}
+
+/**
+ * rhltable_lookup - search hash list table
+ * @hlt:	hash table
+ * @key:	the pointer to the key
+ * @params:	hash table parameters
+ *
+ * Computes the hash value for the key and traverses the bucket chain looking
+ * for a entry with an identical key.  All matching entries are returned
+ * in a list.
+ *
+ * This must only be called under the RCU read lock.
+ *
+ * Returns the list of entries that match the given key.
+ */
+static inline struct rhlist_head *rhltable_lookup(
+	struct rhltable *hlt, const void *key,
+	const struct rhashtable_params params)
+{
+	struct rhash_head *he = __rhashtable_lookup(&hlt->ht, key, params);
+
+	return he ? container_of(he, struct rhlist_head, rhead) : NULL;
+}
+
 /* Internal function, please use rhashtable_insert_fast() instead. This
  * function returns the existing element already in hashes in there is a clash,
  * otherwise it returns an error via ERR_PTR().
  */
 static inline void *__rhashtable_insert_fast(
 	struct rhashtable *ht, const void *key, struct rhash_head *obj,
-	const struct rhashtable_params params)
+	const struct rhashtable_params params, bool rhlist)
 {
 	struct rhashtable_compare_arg arg = {
 		.ht = ht,
 		.key = key,
 	};
-	struct bucket_table *tbl, *new_tbl;
+	struct rhash_head __rcu **pprev;
+	struct bucket_table *tbl;
 	struct rhash_head *head;
 	spinlock_t *lock;
-	unsigned int elasticity;
 	unsigned int hash;
-	void *data = NULL;
-	int err;
+	int elasticity;
+	void *data;
 
-restart:
 	rcu_read_lock();
 
 	tbl = rht_dereference_rcu(ht->tbl, ht);
+	hash = rht_head_hashfn(ht, tbl, obj, params);
+	lock = rht_bucket_lock(tbl, hash);
+	spin_lock_bh(lock);
 
-	/* All insertions must grab the oldest table containing
-	 * the hashed bucket that is yet to be rehashed.
-	 */
-	for (;;) {
-		hash = rht_head_hashfn(ht, tbl, obj, params);
-		lock = rht_bucket_lock(tbl, hash);
-		spin_lock_bh(lock);
-
-		if (tbl->rehash <= hash)
-			break;
-
+	if (unlikely(rht_dereference_bucket(tbl->future_tbl, tbl, hash))) {
+slow_path:
 		spin_unlock_bh(lock);
-		tbl = rht_dereference_rcu(tbl->future_tbl, ht);
+		rcu_read_unlock();
+		return rhashtable_insert_slow(ht, key, obj);
 	}
 
-	new_tbl = rht_dereference_rcu(tbl->future_tbl, ht);
-	if (unlikely(new_tbl)) {
-		tbl = rhashtable_insert_slow(ht, key, obj, new_tbl, &data);
-		if (!IS_ERR_OR_NULL(tbl))
-			goto slow_path;
+	elasticity = ht->elasticity;
+	pprev = &tbl->buckets[hash];
+	rht_for_each(head, tbl, hash) {
+		struct rhlist_head *plist;
+		struct rhlist_head *list;
+
+		elasticity--;
+		if (!key ||
+		    (params.obj_cmpfn ?
+		     params.obj_cmpfn(&arg, rht_obj(ht, head)) :
+		     rhashtable_compare(&arg, rht_obj(ht, head))))
+			continue;
+
+		data = rht_obj(ht, head);
 
-		err = PTR_ERR(tbl);
-		if (err == -EEXIST)
-			err = 0;
+		if (!rhlist)
+			goto out;
 
-		goto out;
-	}
 
-	err = -E2BIG;
-	if (unlikely(rht_grow_above_max(ht, tbl)))
-		goto out;
+		list = container_of(obj, struct rhlist_head, rhead);
+		plist = container_of(head, struct rhlist_head, rhead);
 
-	if (unlikely(rht_grow_above_100(ht, tbl))) {
-slow_path:
-		spin_unlock_bh(lock);
-		err = rhashtable_insert_rehash(ht, tbl);
-		rcu_read_unlock();
-		if (err)
-			return ERR_PTR(err);
+		RCU_INIT_POINTER(list->next, plist);
+		head = rht_dereference_bucket(head->next, tbl, hash);
+		RCU_INIT_POINTER(list->rhead.next, head);
+		rcu_assign_pointer(*pprev, obj);
 
-		goto restart;
+		goto good;
 	}
 
-	err = 0;
-	elasticity = ht->elasticity;
-	rht_for_each(head, tbl, hash) {
-		if (key &&
-		    unlikely(!(params.obj_cmpfn ?
-			       params.obj_cmpfn(&arg, rht_obj(ht, head)) :
-			       rhashtable_compare(&arg, rht_obj(ht, head))))) {
-			data = rht_obj(ht, head);
-			goto out;
-		}
-		if (!--elasticity)
-			goto slow_path;
-	}
+	if (elasticity <= 0)
+		goto slow_path;
+
+	data = ERR_PTR(-E2BIG);
+	if (unlikely(rht_grow_above_max(ht, tbl)))
+		goto out;
+
+	if (unlikely(rht_grow_above_100(ht, tbl)))
+		goto slow_path;
 
 	head = rht_dereference_bucket(tbl->buckets[hash], tbl, hash);
 
 	RCU_INIT_POINTER(obj->next, head);
+	if (rhlist) {
+		struct rhlist_head *list;
+
+		list = container_of(obj, struct rhlist_head, rhead);
+		RCU_INIT_POINTER(list->next, NULL);
+	}
 
 	rcu_assign_pointer(tbl->buckets[hash], obj);
 
@@ -656,11 +752,14 @@ slow_path:
 	if (rht_grow_above_75(ht, tbl))
 		schedule_work(&ht->run_work);
 
+good:
+	data = NULL;
+
 out:
 	spin_unlock_bh(lock);
 	rcu_read_unlock();
 
-	return err ? ERR_PTR(err) : data;
+	return data;
 }
 
 /**
@@ -685,7 +784,7 @@ static inline int rhashtable_insert_fast(
 {
 	void *ret;
 
-	ret = __rhashtable_insert_fast(ht, NULL, obj, params);
+	ret = __rhashtable_insert_fast(ht, NULL, obj, params, false);
 	if (IS_ERR(ret))
 		return PTR_ERR(ret);
 
@@ -693,6 +792,58 @@ static inline int rhashtable_insert_fast(
 }
 
 /**
+ * rhltable_insert_key - insert object into hash list table
+ * @hlt:	hash list table
+ * @key:	the pointer to the key
+ * @list:	pointer to hash list head inside object
+ * @params:	hash table parameters
+ *
+ * Will take a per bucket spinlock to protect against mutual mutations
+ * on the same bucket. Multiple insertions may occur in parallel unless
+ * they map to the same bucket lock.
+ *
+ * It is safe to call this function from atomic context.
+ *
+ * Will trigger an automatic deferred table resizing if the size grows
+ * beyond the watermark indicated by grow_decision() which can be passed
+ * to rhashtable_init().
+ */
+static inline int rhltable_insert_key(
+	struct rhltable *hlt, const void *key, struct rhlist_head *list,
+	const struct rhashtable_params params)
+{
+	return PTR_ERR(__rhashtable_insert_fast(&hlt->ht, key, &list->rhead,
+						params, true));
+}
+
+/**
+ * rhltable_insert - insert object into hash list table
+ * @hlt:	hash list table
+ * @list:	pointer to hash list head inside object
+ * @params:	hash table parameters
+ *
+ * Will take a per bucket spinlock to protect against mutual mutations
+ * on the same bucket. Multiple insertions may occur in parallel unless
+ * they map to the same bucket lock.
+ *
+ * It is safe to call this function from atomic context.
+ *
+ * Will trigger an automatic deferred table resizing if the size grows
+ * beyond the watermark indicated by grow_decision() which can be passed
+ * to rhashtable_init().
+ */
+static inline int rhltable_insert(
+	struct rhltable *hlt, struct rhlist_head *list,
+	const struct rhashtable_params params)
+{
+	const char *key = rht_obj(&hlt->ht, &list->rhead);
+
+	key += params.key_offset;
+
+	return rhltable_insert_key(hlt, key, list, params);
+}
+
+/**
  * rhashtable_lookup_insert_fast - lookup and insert object into hash table
  * @ht:		hash table
  * @obj:	pointer to hash head inside object
@@ -722,7 +873,8 @@ static inline int rhashtable_lookup_insert_fast(
 
 	BUG_ON(ht->p.obj_hashfn);
 
-	ret = __rhashtable_insert_fast(ht, key + ht->p.key_offset, obj, params);
+	ret = __rhashtable_insert_fast(ht, key + ht->p.key_offset, obj, params,
+				       false);
 	if (IS_ERR(ret))
 		return PTR_ERR(ret);
 
@@ -759,7 +911,7 @@ static inline int rhashtable_lookup_insert_key(
 
 	BUG_ON(!ht->p.obj_hashfn || !key);
 
-	ret = __rhashtable_insert_fast(ht, key, obj, params);
+	ret = __rhashtable_insert_fast(ht, key, obj, params, false);
 	if (IS_ERR(ret))
 		return PTR_ERR(ret);
 
@@ -783,13 +935,14 @@ static inline void *rhashtable_lookup_get_insert_key(
 {
 	BUG_ON(!ht->p.obj_hashfn || !key);
 
-	return __rhashtable_insert_fast(ht, key, obj, params);
+	return __rhashtable_insert_fast(ht, key, obj, params, false);
 }
 
 /* Internal function, please use rhashtable_remove_fast() instead */
-static inline int __rhashtable_remove_fast(
+static inline int __rhashtable_remove_fast_one(
 	struct rhashtable *ht, struct bucket_table *tbl,
-	struct rhash_head *obj, const struct rhashtable_params params)
+	struct rhash_head *obj, const struct rhashtable_params params,
+	bool rhlist)
 {
 	struct rhash_head __rcu **pprev;
 	struct rhash_head *he;
@@ -804,39 +957,65 @@ static inline int __rhashtable_remove_fast(
 
 	pprev = &tbl->buckets[hash];
 	rht_for_each(he, tbl, hash) {
+		struct rhlist_head *list;
+
+		list = container_of(he, struct rhlist_head, rhead);
+
 		if (he != obj) {
+			struct rhlist_head __rcu **lpprev;
+
 			pprev = &he->next;
-			continue;
+
+			if (!rhlist)
+				continue;
+
+			do {
+				lpprev = &list->next;
+				list = rht_dereference_bucket(list->next,
+							      tbl, hash);
+			} while (list && obj != &list->rhead);
+
+			if (!list)
+				continue;
+
+			list = rht_dereference_bucket(list->next, tbl, hash);
+			RCU_INIT_POINTER(*lpprev, list);
+			err = 0;
+			break;
 		}
 
-		rcu_assign_pointer(*pprev, obj->next);
-		err = 0;
+		obj = rht_dereference_bucket(obj->next, tbl, hash);
+
+		if (rhlist) {
+			list = rht_dereference_bucket(list->next, tbl, hash);
+			if (list) {
+				RCU_INIT_POINTER(list->rhead.next, obj);
+				obj = &list->rhead;
+			}
+		}
+
+		rcu_assign_pointer(*pprev, obj);
+		err = 1;
 		break;
 	}
 
 	spin_unlock_bh(lock);
 
+	if (err > 0) {
+		atomic_dec(&ht->nelems);
+		if (unlikely(ht->p.automatic_shrinking &&
+			     rht_shrink_below_30(ht, tbl)))
+			schedule_work(&ht->run_work);
+		err = 0;
+	}
+
 	return err;
 }
 
-/**
- * rhashtable_remove_fast - remove object from hash table
- * @ht:		hash table
- * @obj:	pointer to hash head inside object
- * @params:	hash table parameters
- *
- * Since the hash chain is single linked, the removal operation needs to
- * walk the bucket chain upon removal. The removal operation is thus
- * considerable slow if the hash table is not correctly sized.
- *
- * Will automatically shrink the table via rhashtable_expand() if the
- * shrink_decision function specified at rhashtable_init() returns true.
- *
- * Returns zero on success, -ENOENT if the entry could not be found.
- */
-static inline int rhashtable_remove_fast(
+/* Internal function, please use rhashtable_remove_fast() instead */
+static inline int __rhashtable_remove_fast(
 	struct rhashtable *ht, struct rhash_head *obj,
-	const struct rhashtable_params params)
+	const struct rhashtable_params params, bool rhlist)
 {
 	struct bucket_table *tbl;
 	int err;
@@ -850,24 +1029,60 @@ static inline int rhashtable_remove_fast(
 	 * visible then that guarantees the entry to still be in
 	 * the old tbl if it exists.
 	 */
-	while ((err = __rhashtable_remove_fast(ht, tbl, obj, params)) &&
+	while ((err = __rhashtable_remove_fast_one(ht, tbl, obj, params,
+						   rhlist)) &&
 	       (tbl = rht_dereference_rcu(tbl->future_tbl, ht)))
 		;
 
-	if (err)
-		goto out;
-
-	atomic_dec(&ht->nelems);
-	if (unlikely(ht->p.automatic_shrinking &&
-		     rht_shrink_below_30(ht, tbl)))
-		schedule_work(&ht->run_work);
-
-out:
 	rcu_read_unlock();
 
 	return err;
 }
 
+/**
+ * rhashtable_remove_fast - remove object from hash table
+ * @ht:		hash table
+ * @obj:	pointer to hash head inside object
+ * @params:	hash table parameters
+ *
+ * Since the hash chain is single linked, the removal operation needs to
+ * walk the bucket chain upon removal. The removal operation is thus
+ * considerable slow if the hash table is not correctly sized.
+ *
+ * Will automatically shrink the table via rhashtable_expand() if the
+ * shrink_decision function specified at rhashtable_init() returns true.
+ *
+ * Returns zero on success, -ENOENT if the entry could not be found.
+ */
+static inline int rhashtable_remove_fast(
+	struct rhashtable *ht, struct rhash_head *obj,
+	const struct rhashtable_params params)
+{
+	return __rhashtable_remove_fast(ht, obj, params, false);
+}
+
+/**
+ * rhltable_remove - remove object from hash list table
+ * @hlt:	hash list table
+ * @list:	pointer to hash list head inside object
+ * @params:	hash table parameters
+ *
+ * Since the hash chain is single linked, the removal operation needs to
+ * walk the bucket chain upon removal. The removal operation is thus
+ * considerable slow if the hash table is not correctly sized.
+ *
+ * Will automatically shrink the table via rhashtable_expand() if the
+ * shrink_decision function specified at rhashtable_init() returns true.
+ *
+ * Returns zero on success, -ENOENT if the entry could not be found.
+ */
+static inline int rhltable_remove(
+	struct rhltable *hlt, struct rhlist_head *list,
+	const struct rhashtable_params params)
+{
+	return __rhashtable_remove_fast(&hlt->ht, &list->rhead, params, true);
+}
+
 /* Internal function, please use rhashtable_replace_fast() instead */
 static inline int __rhashtable_replace_fast(
 	struct rhashtable *ht, struct bucket_table *tbl,
@@ -958,4 +1173,51 @@ static inline int rhashtable_walk_init(struct rhashtable *ht,
 	return 0;
 }
 
+/**
+ * rhltable_walk_enter - Initialise an iterator
+ * @hlt:	Table to walk over
+ * @iter:	Hash table Iterator
+ *
+ * This function prepares a hash table walk.
+ *
+ * Note that if you restart a walk after rhashtable_walk_stop you
+ * may see the same object twice.  Also, you may miss objects if
+ * there are removals in between rhashtable_walk_stop and the next
+ * call to rhashtable_walk_start.
+ *
+ * For a completely stable walk you should construct your own data
+ * structure outside the hash table.
+ *
+ * This function may sleep so you must not call it from interrupt
+ * context or with spin locks held.
+ *
+ * You must call rhashtable_walk_exit after this function returns.
+ */
+static inline void rhltable_walk_enter(struct rhltable *hlt,
+				       struct rhashtable_iter *iter)
+{
+	return rhashtable_walk_enter(&hlt->ht, iter);
+}
+
+/**
+ * rhltable_free_and_destroy - free elements and destroy hash list table
+ * @hlt:	the hash list table to destroy
+ * @free_fn:	callback to release resources of element
+ * @arg:	pointer passed to free_fn
+ *
+ * See documentation for rhashtable_free_and_destroy.
+ */
+static inline void rhltable_free_and_destroy(struct rhltable *hlt,
+					     void (*free_fn)(void *ptr,
+							     void *arg),
+					     void *arg)
+{
+	return rhashtable_free_and_destroy(&hlt->ht, free_fn, arg);
+}
+
+static inline void rhltable_destroy(struct rhltable *hlt)
+{
+	return rhltable_free_and_destroy(hlt, NULL, NULL);
+}
+
 #endif /* _LINUX_RHASHTABLE_H */
diff --git a/lib/rhashtable.c b/lib/rhashtable.c
index 06c2872..185fc14 100644
--- a/lib/rhashtable.c
+++ b/lib/rhashtable.c
@@ -378,22 +378,8 @@ static void rht_deferred_worker(struct work_struct *work)
 		schedule_work(&ht->run_work);
 }
 
-static bool rhashtable_check_elasticity(struct rhashtable *ht,
-					struct bucket_table *tbl,
-					unsigned int hash)
-{
-	unsigned int elasticity = ht->elasticity;
-	struct rhash_head *head;
-
-	rht_for_each(head, tbl, hash)
-		if (!--elasticity)
-			return true;
-
-	return false;
-}
-
-int rhashtable_insert_rehash(struct rhashtable *ht,
-			     struct bucket_table *tbl)
+static int rhashtable_insert_rehash(struct rhashtable *ht,
+				    struct bucket_table *tbl)
 {
 	struct bucket_table *old_tbl;
 	struct bucket_table *new_tbl;
@@ -439,57 +425,148 @@ fail:
 
 	return err;
 }
-EXPORT_SYMBOL_GPL(rhashtable_insert_rehash);
 
-struct bucket_table *rhashtable_insert_slow(struct rhashtable *ht,
-					    const void *key,
-					    struct rhash_head *obj,
-					    struct bucket_table *tbl,
-					    void **data)
+static void *rhashtable_insert_one(struct rhashtable *ht,
+				   struct bucket_table *tbl, unsigned int hash,
+				   const void *key, struct rhash_head *obj)
 {
+	struct rhashtable_compare_arg arg = {
+		.ht = ht,
+		.key = key,
+	};
+	struct rhash_head __rcu **pprev;
+	struct rhash_head *head;
+	int elasticity;
+
+	elasticity = ht->elasticity;
+	pprev = &tbl->buckets[hash];
+	rht_for_each(head, tbl, hash) {
+		struct rhlist_head *list;
+		struct rhlist_head *plist;
+
+		elasticity--;
+		if (!key ||
+		    (ht->p.obj_cmpfn ?
+		     ht->p.obj_cmpfn(&arg, rht_obj(ht, head)) :
+		     rhashtable_compare(&arg, rht_obj(ht, head))))
+			continue;
+
+		if (!ht->rhlist)
+			return rht_obj(ht, head);
+
+		list = container_of(obj, struct rhlist_head, rhead);
+		plist = container_of(head, struct rhlist_head, rhead);
+
+		RCU_INIT_POINTER(list->next, plist);
+		head = rht_dereference_bucket(head->next, tbl, hash);
+		RCU_INIT_POINTER(list->rhead.next, head);
+		rcu_assign_pointer(*pprev, obj);
+
+		return NULL;
+	}
+
+	if (elasticity <= 0)
+		return ERR_PTR(-EAGAIN);
+
+	return ERR_PTR(-ENOENT);
+}
+
+static void *rhashtable_try_insert(struct rhashtable *ht, const void *key,
+				   struct rhash_head *obj)
+{
+	struct bucket_table *tbl;
 	struct rhash_head *head;
 	unsigned int hash;
-	int err;
+	spinlock_t *lock;
+	void *data;
 
-	tbl = rhashtable_last_table(ht, tbl);
-	hash = head_hashfn(ht, tbl, obj);
-	spin_lock_nested(rht_bucket_lock(tbl, hash), SINGLE_DEPTH_NESTING);
-
-	err = -EEXIST;
-	if (key) {
-		*data = rhashtable_lookup_fast(ht, key, ht->p);
-		if (*data)
-			goto exit;
+	tbl = rht_dereference_rcu(ht->tbl, ht);
+
+	/* All insertions must grab the oldest table containing
+	 * the hashed bucket that is yet to be rehashed.
+	 */
+	for (;;) {
+		hash = rht_head_hashfn(ht, tbl, obj, ht->p);
+		lock = rht_bucket_lock(tbl, hash);
+		spin_lock_bh(lock);
+
+		if (tbl->rehash <= hash)
+			break;
+
+		spin_unlock_bh(lock);
+		tbl = rht_dereference_rcu(tbl->future_tbl, ht);
+	}
+
+	data = rhashtable_insert_one(ht, tbl, hash, key, obj);
+
+	while (PTR_ERR(data) == -ENOENT || PTR_ERR(data) == -EAGAIN) {
+		struct bucket_table *new_tbl;
+
+		new_tbl = rht_dereference_rcu(tbl->future_tbl, ht);
+		if (!new_tbl)
+			break;
+
+		tbl = new_tbl;
+		hash = rht_head_hashfn(ht, tbl, obj, ht->p);
+		spin_lock_nested(rht_bucket_lock(tbl, hash),
+				 SINGLE_DEPTH_NESTING);
+
+		data = rhashtable_insert_one(ht, tbl, hash, key, obj);
+
+		spin_unlock(rht_bucket_lock(tbl, hash));
 	}
 
-	err = -E2BIG;
+	if (PTR_ERR(data) != -ENOENT)
+		goto exit;
+
+	data = ERR_PTR(-E2BIG);
 	if (unlikely(rht_grow_above_max(ht, tbl)))
 		goto exit;
 
-	err = -EAGAIN;
-	if (rhashtable_check_elasticity(ht, tbl, hash) ||
-	    rht_grow_above_100(ht, tbl))
+	data = ERR_PTR(-EAGAIN);
+	if (unlikely(rht_grow_above_100(ht, tbl)))
 		goto exit;
 
-	err = 0;
+	data = NULL;
 
 	head = rht_dereference_bucket(tbl->buckets[hash], tbl, hash);
 
 	RCU_INIT_POINTER(obj->next, head);
+	if (ht->rhlist) {
+		struct rhlist_head *list;
+
+		list = container_of(obj, struct rhlist_head, rhead);
+		RCU_INIT_POINTER(list->next, NULL);
+	}
 
 	rcu_assign_pointer(tbl->buckets[hash], obj);
 
 	atomic_inc(&ht->nelems);
+	if (rht_grow_above_75(ht, tbl))
+		schedule_work(&ht->run_work);
 
 exit:
-	spin_unlock(rht_bucket_lock(tbl, hash));
+	spin_unlock_bh(lock);
 
-	if (err == 0)
-		return NULL;
-	else if (err == -EAGAIN)
-		return tbl;
-	else
-		return ERR_PTR(err);
+	if (PTR_ERR(data) == -EAGAIN)
+		data = ERR_PTR(rhashtable_insert_rehash(ht, tbl) ?:
+			       -EAGAIN);
+
+	return data;
+}
+
+void *rhashtable_insert_slow(struct rhashtable *ht, const void *key,
+			     struct rhash_head *obj)
+{
+	void *data;
+
+	do {
+		rcu_read_lock();
+		data = rhashtable_try_insert(ht, key, obj);
+		rcu_read_unlock();
+	} while (PTR_ERR(data) == -EAGAIN);
+
+	return data;
 }
 EXPORT_SYMBOL_GPL(rhashtable_insert_slow);
 
@@ -593,11 +670,16 @@ EXPORT_SYMBOL_GPL(rhashtable_walk_start);
 void *rhashtable_walk_next(struct rhashtable_iter *iter)
 {
 	struct bucket_table *tbl = iter->walker.tbl;
+	struct rhlist_head *list = iter->list;
 	struct rhashtable *ht = iter->ht;
 	struct rhash_head *p = iter->p;
+	bool rhlist = ht->rhlist;
 
 	if (p) {
-		p = rht_dereference_bucket_rcu(p->next, tbl, iter->slot);
+		if (!rhlist || !(list = rcu_dereference(list->next))) {
+			p = rcu_dereference(p->next);
+			list = container_of(p, struct rhlist_head, rhead);
+		}
 		goto next;
 	}
 
@@ -605,6 +687,18 @@ void *rhashtable_walk_next(struct rhashtable_iter *iter)
 		int skip = iter->skip;
 
 		rht_for_each_rcu(p, tbl, iter->slot) {
+			if (rhlist) {
+				list = container_of(p, struct rhlist_head,
+						    rhead);
+				do {
+					if (!skip)
+						goto next;
+					skip--;
+					list = rcu_dereference(list->next);
+				} while (list);
+
+				continue;
+			}
 			if (!skip)
 				break;
 			skip--;
@@ -614,7 +708,8 @@ next:
 		if (!rht_is_a_nulls(p)) {
 			iter->skip++;
 			iter->p = p;
-			return rht_obj(ht, p);
+			iter->list = list;
+			return rht_obj(ht, rhlist ? &list->rhead : p);
 		}
 
 		iter->skip = 0;
@@ -803,6 +898,48 @@ int rhashtable_init(struct rhashtable *ht,
 EXPORT_SYMBOL_GPL(rhashtable_init);
 
 /**
+ * rhltable_init - initialize a new hash list table
+ * @hlt:	hash list table to be initialized
+ * @params:	configuration parameters
+ *
+ * Initializes a new hash list table.
+ *
+ * See documentation for rhashtable_init.
+ */
+int rhltable_init(struct rhltable *hlt, const struct rhashtable_params *params)
+{
+	int err;
+
+	/* No rhlist NULLs marking for now. */
+	if (params->nulls_base)
+		return -EINVAL;
+
+	err = rhashtable_init(&hlt->ht, params);
+	hlt->ht.rhlist = true;
+	return err;
+}
+EXPORT_SYMBOL_GPL(rhltable_init);
+
+static void rhashtable_free_one(struct rhashtable *ht, struct rhash_head *obj,
+				void (*free_fn)(void *ptr, void *arg),
+				void *arg)
+{
+	struct rhlist_head *list;
+
+	if (!ht->rhlist) {
+		free_fn(rht_obj(ht, obj), arg);
+		return;
+	}
+
+	list = container_of(obj, struct rhlist_head, rhead);
+	do {
+		obj = &list->rhead;
+		list = rht_dereference(list->next, ht);
+		free_fn(rht_obj(ht, obj), arg);
+	} while (list);
+}
+
+/**
  * rhashtable_free_and_destroy - free elements and destroy hash table
  * @ht:		the hash table to destroy
  * @free_fn:	callback to release resources of element
@@ -839,7 +976,7 @@ void rhashtable_free_and_destroy(struct rhashtable *ht,
 			     pos = next,
 			     next = !rht_is_a_nulls(pos) ?
 					rht_dereference(pos->next, ht) : NULL)
-				free_fn(rht_obj(ht, pos), arg);
+				rhashtable_free_one(ht, pos, free_fn, arg);
 		}
 	}
 

[PATCH 1/2] rhashtable: Add rhlist interface

[Herbert Xu]

The insecure_elasticity setting is an ugly wart brought out by
users who need to insert duplicate objects (that is, distinct
objects with identical keys) into the same table.

In fact, those users have a much bigger problem.  Once those
duplicate objects are inserted, they don't have an interface to
find them (unless you count the walker interface which walks
over the entire table).

Some users have resorted to doing a manual walk over the hash
table which is of course broken because they don't handle the
potential existence of multiple hash tables.  The result is that
they will break sporadically when they encounter a hash table
resize/rehash.

This patch provides a way out for those users, at the expense
of an extra pointer per object.  Essentially each object is now
a list of objects carrying the same key.  The hash table will
only see the lists so nothing changes as far as rhashtable is
concerned.

To use this new interface, you need to insert a struct rhlist_head
into your objects instead of struct rhash_head.  While the hash
table is unchanged, for type-safety you'll need to use struct
rhltable instead of struct rhashtable.  All the existing interfaces
have been duplicated for rhlist, including the hash table walker.

One missing feature is nulls marking because AFAIK the only potential
user of it does not need duplicate objects.  Should anyone need
this it shouldn't be too hard to add.

Signed-off-by: Herbert Xu <herbert-lOAM2aK0SrRLBo1qDEOMRrpzq4S04n8Q@public.gmane.org>
---

 include/linux/rhashtable.h |  490 ++++++++++++++++++++++++++++++++++-----------
 lib/rhashtable.c           |  231 ++++++++++++++++-----
 2 files changed, 560 insertions(+), 161 deletions(-)

diff --git a/include/linux/rhashtable.h b/include/linux/rhashtable.h
index fd82584..dc7bea6 100644
--- a/include/linux/rhashtable.h
+++ b/include/linux/rhashtable.h
@@ -1,7 +1,7 @@
 /*
  * Resizable, Scalable, Concurrent Hash Table
  *
- * Copyright (c) 2015 Herbert Xu <herbert-lOAM2aK0SrRLBo1qDEOMRrpzq4S04n8Q@public.gmane.org>
+ * Copyright (c) 2015-2016 Herbert Xu <herbert-lOAM2aK0SrRLBo1qDEOMRrpzq4S04n8Q@public.gmane.org>
  * Copyright (c) 2014-2015 Thomas Graf <tgraf-G/eBtMaohhA@public.gmane.org>
  * Copyright (c) 2008-2014 Patrick McHardy <kaber-dcUjhNyLwpNeoWH0uzbU5w@public.gmane.org>
  *
@@ -53,6 +53,11 @@ struct rhash_head {
 	struct rhash_head __rcu		*next;
 };
 
+struct rhlist_head {
+	struct rhash_head		rhead;
+	struct rhlist_head __rcu	*next;
+};
+
 /**
  * struct bucket_table - Table of hash buckets
  * @size: Number of hash buckets
@@ -137,6 +142,7 @@ struct rhashtable_params {
  * @key_len: Key length for hashfn
  * @elasticity: Maximum chain length before rehash
  * @p: Configuration parameters
+ * @rhlist: True if this is an rhltable
  * @run_work: Deferred worker to expand/shrink asynchronously
  * @mutex: Mutex to protect current/future table swapping
  * @lock: Spin lock to protect walker list
@@ -147,12 +153,21 @@ struct rhashtable {
 	unsigned int			key_len;
 	unsigned int			elasticity;
 	struct rhashtable_params	p;
+	bool				rhlist;
 	struct work_struct		run_work;
 	struct mutex                    mutex;
 	spinlock_t			lock;
 };
 
 /**
+ * struct rhltable - Hash table with duplicate objects in a list
+ * @ht: Underlying rhtable
+ */
+struct rhltable {
+	struct rhashtable ht;
+};
+
+/**
  * struct rhashtable_walker - Hash table walker
  * @list: List entry on list of walkers
  * @tbl: The table that we were walking over
@@ -163,9 +178,10 @@ struct rhashtable_walker {
 };
 
 /**
- * struct rhashtable_iter - Hash table iterator, fits into netlink cb
+ * struct rhashtable_iter - Hash table iterator
  * @ht: Table to iterate through
  * @p: Current pointer
+ * @list: Current hash list pointer
  * @walker: Associated rhashtable walker
  * @slot: Current slot
  * @skip: Number of entries to skip in slot
@@ -173,6 +189,7 @@ struct rhashtable_walker {
 struct rhashtable_iter {
 	struct rhashtable *ht;
 	struct rhash_head *p;
+	struct rhlist_head *list;
 	struct rhashtable_walker walker;
 	unsigned int slot;
 	unsigned int skip;
@@ -339,13 +356,11 @@ static inline int lockdep_rht_bucket_is_held(const struct bucket_table *tbl,
 
 int rhashtable_init(struct rhashtable *ht,
 		    const struct rhashtable_params *params);
+int rhltable_init(struct rhltable *hlt,
+		  const struct rhashtable_params *params);
 
-struct bucket_table *rhashtable_insert_slow(struct rhashtable *ht,
-					    const void *key,
-					    struct rhash_head *obj,
-					    struct bucket_table *old_tbl,
-					    void **data);
-int rhashtable_insert_rehash(struct rhashtable *ht, struct bucket_table *tbl);
+void *rhashtable_insert_slow(struct rhashtable *ht, const void *key,
+			     struct rhash_head *obj);
 
 void rhashtable_walk_enter(struct rhashtable *ht,
 			   struct rhashtable_iter *iter);
@@ -507,6 +522,31 @@ void rhashtable_destroy(struct rhashtable *ht);
 	rht_for_each_entry_rcu_continue(tpos, pos, (tbl)->buckets[hash],\
 					tbl, hash, member)
 
+/**
+ * rhl_for_each_rcu - iterate over rcu hash table list
+ * @pos:	the &struct rlist_head to use as a loop cursor.
+ * @list:	the head of the list
+ *
+ * This hash chain list-traversal primitive should be used on the
+ * list returned by rhltable_lookup.
+ */
+#define rhl_for_each_rcu(pos, list)					\
+	for (pos = list; pos; pos = rcu_dereference_raw(pos->next))
+
+/**
+ * rhl_for_each_entry_rcu - iterate over rcu hash table list of given type
+ * @tpos:	the type * to use as a loop cursor.
+ * @pos:	the &struct rlist_head to use as a loop cursor.
+ * @list:	the head of the list
+ * @member:	name of the &struct rlist_head within the hashable struct.
+ *
+ * This hash chain list-traversal primitive should be used on the
+ * list returned by rhltable_lookup.
+ */
+#define rhl_for_each_entry_rcu(tpos, pos, list, member)			\
+	for (pos = list; pos && rht_entry(tpos, pos, member);		\
+	     pos = rcu_dereference_raw(pos->next))
+
 static inline int rhashtable_compare(struct rhashtable_compare_arg *arg,
 				     const void *obj)
 {
@@ -516,18 +556,8 @@ static inline int rhashtable_compare(struct rhashtable_compare_arg *arg,
 	return memcmp(ptr + ht->p.key_offset, arg->key, ht->p.key_len);
 }
 
-/**
- * rhashtable_lookup_fast - search hash table, inlined version
- * @ht:		hash table
- * @key:	the pointer to the key
- * @params:	hash table parameters
- *
- * Computes the hash value for the key and traverses the bucket chain looking
- * for a entry with an identical key. The first matching entry is returned.
- *
- * Returns the first entry on which the compare function returned true.
- */
-static inline void *rhashtable_lookup_fast(
+/* Internal function, do not use. */
+static inline struct rhash_head *__rhashtable_lookup(
 	struct rhashtable *ht, const void *key,
 	const struct rhashtable_params params)
 {
@@ -539,8 +569,6 @@ static inline void *rhashtable_lookup_fast(
 	struct rhash_head *he;
 	unsigned int hash;
 
-	rcu_read_lock();
-
 	tbl = rht_dereference_rcu(ht->tbl, ht);
 restart:
 	hash = rht_key_hashfn(ht, tbl, key, params);
@@ -549,8 +577,7 @@ restart:
 		    params.obj_cmpfn(&arg, rht_obj(ht, he)) :
 		    rhashtable_compare(&arg, rht_obj(ht, he)))
 			continue;
-		rcu_read_unlock();
-		return rht_obj(ht, he);
+		return he;
 	}
 
 	/* Ensure we see any new tables. */
@@ -559,96 +586,165 @@ restart:
 	tbl = rht_dereference_rcu(tbl->future_tbl, ht);
 	if (unlikely(tbl))
 		goto restart;
-	rcu_read_unlock();
 
 	return NULL;
 }
 
+/**
+ * rhashtable_lookup - search hash table
+ * @ht:		hash table
+ * @key:	the pointer to the key
+ * @params:	hash table parameters
+ *
+ * Computes the hash value for the key and traverses the bucket chain looking
+ * for a entry with an identical key. The first matching entry is returned.
+ *
+ * This must only be called under the RCU read lock.
+ *
+ * Returns the first entry on which the compare function returned true.
+ */
+static inline void *rhashtable_lookup(
+	struct rhashtable *ht, const void *key,
+	const struct rhashtable_params params)
+{
+	struct rhash_head *he = __rhashtable_lookup(ht, key, params);
+
+	return he ? rht_obj(ht, he) : NULL;
+}
+
+/**
+ * rhashtable_lookup_fast - search hash table, without RCU read lock
+ * @ht:		hash table
+ * @key:	the pointer to the key
+ * @params:	hash table parameters
+ *
+ * Computes the hash value for the key and traverses the bucket chain looking
+ * for a entry with an identical key. The first matching entry is returned.
+ *
+ * Only use this function when you have other mechanisms guaranteeing
+ * that the object won't go away after the RCU read lock is released.
+ *
+ * Returns the first entry on which the compare function returned true.
+ */
+static inline void *rhashtable_lookup_fast(
+	struct rhashtable *ht, const void *key,
+	const struct rhashtable_params params)
+{
+	void *obj;
+
+	rcu_read_lock();
+	obj = rhashtable_lookup(ht, key, params);
+	rcu_read_unlock();
+
+	return obj;
+}
+
+/**
+ * rhltable_lookup - search hash list table
+ * @hlt:	hash table
+ * @key:	the pointer to the key
+ * @params:	hash table parameters
+ *
+ * Computes the hash value for the key and traverses the bucket chain looking
+ * for a entry with an identical key.  All matching entries are returned
+ * in a list.
+ *
+ * This must only be called under the RCU read lock.
+ *
+ * Returns the list of entries that match the given key.
+ */
+static inline struct rhlist_head *rhltable_lookup(
+	struct rhltable *hlt, const void *key,
+	const struct rhashtable_params params)
+{
+	struct rhash_head *he = __rhashtable_lookup(&hlt->ht, key, params);
+
+	return he ? container_of(he, struct rhlist_head, rhead) : NULL;
+}
+
 /* Internal function, please use rhashtable_insert_fast() instead. This
  * function returns the existing element already in hashes in there is a clash,
  * otherwise it returns an error via ERR_PTR().
  */
 static inline void *__rhashtable_insert_fast(
 	struct rhashtable *ht, const void *key, struct rhash_head *obj,
-	const struct rhashtable_params params)
+	const struct rhashtable_params params, bool rhlist)
 {
 	struct rhashtable_compare_arg arg = {
 		.ht = ht,
 		.key = key,
 	};
-	struct bucket_table *tbl, *new_tbl;
+	struct rhash_head __rcu **pprev;
+	struct bucket_table *tbl;
 	struct rhash_head *head;
 	spinlock_t *lock;
-	unsigned int elasticity;
 	unsigned int hash;
-	void *data = NULL;
-	int err;
+	int elasticity;
+	void *data;
 
-restart:
 	rcu_read_lock();
 
 	tbl = rht_dereference_rcu(ht->tbl, ht);
+	hash = rht_head_hashfn(ht, tbl, obj, params);
+	lock = rht_bucket_lock(tbl, hash);
+	spin_lock_bh(lock);
 
-	/* All insertions must grab the oldest table containing
-	 * the hashed bucket that is yet to be rehashed.
-	 */
-	for (;;) {
-		hash = rht_head_hashfn(ht, tbl, obj, params);
-		lock = rht_bucket_lock(tbl, hash);
-		spin_lock_bh(lock);
-
-		if (tbl->rehash <= hash)
-			break;
-
+	if (unlikely(rht_dereference_bucket(tbl->future_tbl, tbl, hash))) {
+slow_path:
 		spin_unlock_bh(lock);
-		tbl = rht_dereference_rcu(tbl->future_tbl, ht);
+		rcu_read_unlock();
+		return rhashtable_insert_slow(ht, key, obj);
 	}
 
-	new_tbl = rht_dereference_rcu(tbl->future_tbl, ht);
-	if (unlikely(new_tbl)) {
-		tbl = rhashtable_insert_slow(ht, key, obj, new_tbl, &data);
-		if (!IS_ERR_OR_NULL(tbl))
-			goto slow_path;
+	elasticity = ht->elasticity;
+	pprev = &tbl->buckets[hash];
+	rht_for_each(head, tbl, hash) {
+		struct rhlist_head *plist;
+		struct rhlist_head *list;
+
+		elasticity--;
+		if (!key ||
+		    (params.obj_cmpfn ?
+		     params.obj_cmpfn(&arg, rht_obj(ht, head)) :
+		     rhashtable_compare(&arg, rht_obj(ht, head))))
+			continue;
+
+		data = rht_obj(ht, head);
 
-		err = PTR_ERR(tbl);
-		if (err == -EEXIST)
-			err = 0;
+		if (!rhlist)
+			goto out;
 
-		goto out;
-	}
 
-	err = -E2BIG;
-	if (unlikely(rht_grow_above_max(ht, tbl)))
-		goto out;
+		list = container_of(obj, struct rhlist_head, rhead);
+		plist = container_of(head, struct rhlist_head, rhead);
 
-	if (unlikely(rht_grow_above_100(ht, tbl))) {
-slow_path:
-		spin_unlock_bh(lock);
-		err = rhashtable_insert_rehash(ht, tbl);
-		rcu_read_unlock();
-		if (err)
-			return ERR_PTR(err);
+		RCU_INIT_POINTER(list->next, plist);
+		head = rht_dereference_bucket(head->next, tbl, hash);
+		RCU_INIT_POINTER(list->rhead.next, head);
+		rcu_assign_pointer(*pprev, obj);
 
-		goto restart;
+		goto good;
 	}
 
-	err = 0;
-	elasticity = ht->elasticity;
-	rht_for_each(head, tbl, hash) {
-		if (key &&
-		    unlikely(!(params.obj_cmpfn ?
-			       params.obj_cmpfn(&arg, rht_obj(ht, head)) :
-			       rhashtable_compare(&arg, rht_obj(ht, head))))) {
-			data = rht_obj(ht, head);
-			goto out;
-		}
-		if (!--elasticity)
-			goto slow_path;
-	}
+	if (elasticity <= 0)
+		goto slow_path;
+
+	data = ERR_PTR(-E2BIG);
+	if (unlikely(rht_grow_above_max(ht, tbl)))
+		goto out;
+
+	if (unlikely(rht_grow_above_100(ht, tbl)))
+		goto slow_path;
 
 	head = rht_dereference_bucket(tbl->buckets[hash], tbl, hash);
 
 	RCU_INIT_POINTER(obj->next, head);
+	if (rhlist) {
+		struct rhlist_head *list;
+
+		list = container_of(obj, struct rhlist_head, rhead);
+		RCU_INIT_POINTER(list->next, NULL);
+	}
 
 	rcu_assign_pointer(tbl->buckets[hash], obj);
 
@@ -656,11 +752,14 @@ slow_path:
 	if (rht_grow_above_75(ht, tbl))
 		schedule_work(&ht->run_work);
 
+good:
+	data = NULL;
+
 out:
 	spin_unlock_bh(lock);
 	rcu_read_unlock();
 
-	return err ? ERR_PTR(err) : data;
+	return data;
 }
 
 /**
@@ -685,7 +784,7 @@ static inline int rhashtable_insert_fast(
 {
 	void *ret;
 
-	ret = __rhashtable_insert_fast(ht, NULL, obj, params);
+	ret = __rhashtable_insert_fast(ht, NULL, obj, params, false);
 	if (IS_ERR(ret))
 		return PTR_ERR(ret);
 
@@ -693,6 +792,58 @@ static inline int rhashtable_insert_fast(
 }
 
 /**
+ * rhltable_insert_key - insert object into hash list table
+ * @hlt:	hash list table
+ * @key:	the pointer to the key
+ * @list:	pointer to hash list head inside object
+ * @params:	hash table parameters
+ *
+ * Will take a per bucket spinlock to protect against mutual mutations
+ * on the same bucket. Multiple insertions may occur in parallel unless
+ * they map to the same bucket lock.
+ *
+ * It is safe to call this function from atomic context.
+ *
+ * Will trigger an automatic deferred table resizing if the size grows
+ * beyond the watermark indicated by grow_decision() which can be passed
+ * to rhashtable_init().
+ */
+static inline int rhltable_insert_key(
+	struct rhltable *hlt, const void *key, struct rhlist_head *list,
+	const struct rhashtable_params params)
+{
+	return PTR_ERR(__rhashtable_insert_fast(&hlt->ht, key, &list->rhead,
+						params, true));
+}
+
+/**
+ * rhltable_insert - insert object into hash list table
+ * @hlt:	hash list table
+ * @list:	pointer to hash list head inside object
+ * @params:	hash table parameters
+ *
+ * Will take a per bucket spinlock to protect against mutual mutations
+ * on the same bucket. Multiple insertions may occur in parallel unless
+ * they map to the same bucket lock.
+ *
+ * It is safe to call this function from atomic context.
+ *
+ * Will trigger an automatic deferred table resizing if the size grows
+ * beyond the watermark indicated by grow_decision() which can be passed
+ * to rhashtable_init().
+ */
+static inline int rhltable_insert(
+	struct rhltable *hlt, struct rhlist_head *list,
+	const struct rhashtable_params params)
+{
+	const char *key = rht_obj(&hlt->ht, &list->rhead);
+
+	key += params.key_offset;
+
+	return rhltable_insert_key(hlt, key, list, params);
+}
+
+/**
  * rhashtable_lookup_insert_fast - lookup and insert object into hash table
  * @ht:		hash table
  * @obj:	pointer to hash head inside object
@@ -722,7 +873,8 @@ static inline int rhashtable_lookup_insert_fast(
 
 	BUG_ON(ht->p.obj_hashfn);
 
-	ret = __rhashtable_insert_fast(ht, key + ht->p.key_offset, obj, params);
+	ret = __rhashtable_insert_fast(ht, key + ht->p.key_offset, obj, params,
+				       false);
 	if (IS_ERR(ret))
 		return PTR_ERR(ret);
 
@@ -759,7 +911,7 @@ static inline int rhashtable_lookup_insert_key(
 
 	BUG_ON(!ht->p.obj_hashfn || !key);
 
-	ret = __rhashtable_insert_fast(ht, key, obj, params);
+	ret = __rhashtable_insert_fast(ht, key, obj, params, false);
 	if (IS_ERR(ret))
 		return PTR_ERR(ret);
 
@@ -783,13 +935,14 @@ static inline void *rhashtable_lookup_get_insert_key(
 {
 	BUG_ON(!ht->p.obj_hashfn || !key);
 
-	return __rhashtable_insert_fast(ht, key, obj, params);
+	return __rhashtable_insert_fast(ht, key, obj, params, false);
 }
 
 /* Internal function, please use rhashtable_remove_fast() instead */
-static inline int __rhashtable_remove_fast(
+static inline int __rhashtable_remove_fast_one(
 	struct rhashtable *ht, struct bucket_table *tbl,
-	struct rhash_head *obj, const struct rhashtable_params params)
+	struct rhash_head *obj, const struct rhashtable_params params,
+	bool rhlist)
 {
 	struct rhash_head __rcu **pprev;
 	struct rhash_head *he;
@@ -804,39 +957,65 @@ static inline int __rhashtable_remove_fast(
 
 	pprev = &tbl->buckets[hash];
 	rht_for_each(he, tbl, hash) {
+		struct rhlist_head *list;
+
+		list = container_of(he, struct rhlist_head, rhead);
+
 		if (he != obj) {
+			struct rhlist_head __rcu **lpprev;
+
 			pprev = &he->next;
-			continue;
+
+			if (!rhlist)
+				continue;
+
+			do {
+				lpprev = &list->next;
+				list = rht_dereference_bucket(list->next,
+							      tbl, hash);
+			} while (list && obj != &list->rhead);
+
+			if (!list)
+				continue;
+
+			list = rht_dereference_bucket(list->next, tbl, hash);
+			RCU_INIT_POINTER(*lpprev, list);
+			err = 0;
+			break;
 		}
 
-		rcu_assign_pointer(*pprev, obj->next);
-		err = 0;
+		obj = rht_dereference_bucket(obj->next, tbl, hash);
+
+		if (rhlist) {
+			list = rht_dereference_bucket(list->next, tbl, hash);
+			if (list) {
+				RCU_INIT_POINTER(list->rhead.next, obj);
+				obj = &list->rhead;
+			}
+		}
+
+		rcu_assign_pointer(*pprev, obj);
+		err = 1;
 		break;
 	}
 
 	spin_unlock_bh(lock);
 
+	if (err > 0) {
+		atomic_dec(&ht->nelems);
+		if (unlikely(ht->p.automatic_shrinking &&
+			     rht_shrink_below_30(ht, tbl)))
+			schedule_work(&ht->run_work);
+		err = 0;
+	}
+
 	return err;
 }
 
-/**
- * rhashtable_remove_fast - remove object from hash table
- * @ht:		hash table
- * @obj:	pointer to hash head inside object
- * @params:	hash table parameters
- *
- * Since the hash chain is single linked, the removal operation needs to
- * walk the bucket chain upon removal. The removal operation is thus
- * considerable slow if the hash table is not correctly sized.
- *
- * Will automatically shrink the table via rhashtable_expand() if the
- * shrink_decision function specified at rhashtable_init() returns true.
- *
- * Returns zero on success, -ENOENT if the entry could not be found.
- */
-static inline int rhashtable_remove_fast(
+/* Internal function, please use rhashtable_remove_fast() instead */
+static inline int __rhashtable_remove_fast(
 	struct rhashtable *ht, struct rhash_head *obj,
-	const struct rhashtable_params params)
+	const struct rhashtable_params params, bool rhlist)
 {
 	struct bucket_table *tbl;
 	int err;
@@ -850,24 +1029,60 @@ static inline int rhashtable_remove_fast(
 	 * visible then that guarantees the entry to still be in
 	 * the old tbl if it exists.
 	 */
-	while ((err = __rhashtable_remove_fast(ht, tbl, obj, params)) &&
+	while ((err = __rhashtable_remove_fast_one(ht, tbl, obj, params,
+						   rhlist)) &&
 	       (tbl = rht_dereference_rcu(tbl->future_tbl, ht)))
 		;
 
-	if (err)
-		goto out;
-
-	atomic_dec(&ht->nelems);
-	if (unlikely(ht->p.automatic_shrinking &&
-		     rht_shrink_below_30(ht, tbl)))
-		schedule_work(&ht->run_work);
-
-out:
 	rcu_read_unlock();
 
 	return err;
 }
 
+/**
+ * rhashtable_remove_fast - remove object from hash table
+ * @ht:		hash table
+ * @obj:	pointer to hash head inside object
+ * @params:	hash table parameters
+ *
+ * Since the hash chain is single linked, the removal operation needs to
+ * walk the bucket chain upon removal. The removal operation is thus
+ * considerable slow if the hash table is not correctly sized.
+ *
+ * Will automatically shrink the table via rhashtable_expand() if the
+ * shrink_decision function specified at rhashtable_init() returns true.
+ *
+ * Returns zero on success, -ENOENT if the entry could not be found.
+ */
+static inline int rhashtable_remove_fast(
+	struct rhashtable *ht, struct rhash_head *obj,
+	const struct rhashtable_params params)
+{
+	return __rhashtable_remove_fast(ht, obj, params, false);
+}
+
+/**
+ * rhltable_remove - remove object from hash list table
+ * @hlt:	hash list table
+ * @list:	pointer to hash list head inside object
+ * @params:	hash table parameters
+ *
+ * Since the hash chain is single linked, the removal operation needs to
+ * walk the bucket chain upon removal. The removal operation is thus
+ * considerable slow if the hash table is not correctly sized.
+ *
+ * Will automatically shrink the table via rhashtable_expand() if the
+ * shrink_decision function specified at rhashtable_init() returns true.
+ *
+ * Returns zero on success, -ENOENT if the entry could not be found.
+ */
+static inline int rhltable_remove(
+	struct rhltable *hlt, struct rhlist_head *list,
+	const struct rhashtable_params params)
+{
+	return __rhashtable_remove_fast(&hlt->ht, &list->rhead, params, true);
+}
+
 /* Internal function, please use rhashtable_replace_fast() instead */
 static inline int __rhashtable_replace_fast(
 	struct rhashtable *ht, struct bucket_table *tbl,
@@ -958,4 +1173,51 @@ static inline int rhashtable_walk_init(struct rhashtable *ht,
 	return 0;
 }
 
+/**
+ * rhltable_walk_enter - Initialise an iterator
+ * @hlt:	Table to walk over
+ * @iter:	Hash table Iterator
+ *
+ * This function prepares a hash table walk.
+ *
+ * Note that if you restart a walk after rhashtable_walk_stop you
+ * may see the same object twice.  Also, you may miss objects if
+ * there are removals in between rhashtable_walk_stop and the next
+ * call to rhashtable_walk_start.
+ *
+ * For a completely stable walk you should construct your own data
+ * structure outside the hash table.
+ *
+ * This function may sleep so you must not call it from interrupt
+ * context or with spin locks held.
+ *
+ * You must call rhashtable_walk_exit after this function returns.
+ */
+static inline void rhltable_walk_enter(struct rhltable *hlt,
+				       struct rhashtable_iter *iter)
+{
+	return rhashtable_walk_enter(&hlt->ht, iter);
+}
+
+/**
+ * rhltable_free_and_destroy - free elements and destroy hash list table
+ * @hlt:	the hash list table to destroy
+ * @free_fn:	callback to release resources of element
+ * @arg:	pointer passed to free_fn
+ *
+ * See documentation for rhashtable_free_and_destroy.
+ */
+static inline void rhltable_free_and_destroy(struct rhltable *hlt,
+					     void (*free_fn)(void *ptr,
+							     void *arg),
+					     void *arg)
+{
+	return rhashtable_free_and_destroy(&hlt->ht, free_fn, arg);
+}
+
+static inline void rhltable_destroy(struct rhltable *hlt)
+{
+	return rhltable_free_and_destroy(hlt, NULL, NULL);
+}
+
 #endif /* _LINUX_RHASHTABLE_H */
diff --git a/lib/rhashtable.c b/lib/rhashtable.c
index 06c2872..185fc14 100644
--- a/lib/rhashtable.c
+++ b/lib/rhashtable.c
@@ -378,22 +378,8 @@ static void rht_deferred_worker(struct work_struct *work)
 		schedule_work(&ht->run_work);
 }
 
-static bool rhashtable_check_elasticity(struct rhashtable *ht,
-					struct bucket_table *tbl,
-					unsigned int hash)
-{
-	unsigned int elasticity = ht->elasticity;
-	struct rhash_head *head;
-
-	rht_for_each(head, tbl, hash)
-		if (!--elasticity)
-			return true;
-
-	return false;
-}
-
-int rhashtable_insert_rehash(struct rhashtable *ht,
-			     struct bucket_table *tbl)
+static int rhashtable_insert_rehash(struct rhashtable *ht,
+				    struct bucket_table *tbl)
 {
 	struct bucket_table *old_tbl;
 	struct bucket_table *new_tbl;
@@ -439,57 +425,148 @@ fail:
 
 	return err;
 }
-EXPORT_SYMBOL_GPL(rhashtable_insert_rehash);
 
-struct bucket_table *rhashtable_insert_slow(struct rhashtable *ht,
-					    const void *key,
-					    struct rhash_head *obj,
-					    struct bucket_table *tbl,
-					    void **data)
+static void *rhashtable_insert_one(struct rhashtable *ht,
+				   struct bucket_table *tbl, unsigned int hash,
+				   const void *key, struct rhash_head *obj)
 {
+	struct rhashtable_compare_arg arg = {
+		.ht = ht,
+		.key = key,
+	};
+	struct rhash_head __rcu **pprev;
+	struct rhash_head *head;
+	int elasticity;
+
+	elasticity = ht->elasticity;
+	pprev = &tbl->buckets[hash];
+	rht_for_each(head, tbl, hash) {
+		struct rhlist_head *list;
+		struct rhlist_head *plist;
+
+		elasticity--;
+		if (!key ||
+		    (ht->p.obj_cmpfn ?
+		     ht->p.obj_cmpfn(&arg, rht_obj(ht, head)) :
+		     rhashtable_compare(&arg, rht_obj(ht, head))))
+			continue;
+
+		if (!ht->rhlist)
+			return rht_obj(ht, head);
+
+		list = container_of(obj, struct rhlist_head, rhead);
+		plist = container_of(head, struct rhlist_head, rhead);
+
+		RCU_INIT_POINTER(list->next, plist);
+		head = rht_dereference_bucket(head->next, tbl, hash);
+		RCU_INIT_POINTER(list->rhead.next, head);
+		rcu_assign_pointer(*pprev, obj);
+
+		return NULL;
+	}
+
+	if (elasticity <= 0)
+		return ERR_PTR(-EAGAIN);
+
+	return ERR_PTR(-ENOENT);
+}
+
+static void *rhashtable_try_insert(struct rhashtable *ht, const void *key,
+				   struct rhash_head *obj)
+{
+	struct bucket_table *tbl;
 	struct rhash_head *head;
 	unsigned int hash;
-	int err;
+	spinlock_t *lock;
+	void *data;
 
-	tbl = rhashtable_last_table(ht, tbl);
-	hash = head_hashfn(ht, tbl, obj);
-	spin_lock_nested(rht_bucket_lock(tbl, hash), SINGLE_DEPTH_NESTING);
-
-	err = -EEXIST;
-	if (key) {
-		*data = rhashtable_lookup_fast(ht, key, ht->p);
-		if (*data)
-			goto exit;
+	tbl = rht_dereference_rcu(ht->tbl, ht);
+
+	/* All insertions must grab the oldest table containing
+	 * the hashed bucket that is yet to be rehashed.
+	 */
+	for (;;) {
+		hash = rht_head_hashfn(ht, tbl, obj, ht->p);
+		lock = rht_bucket_lock(tbl, hash);
+		spin_lock_bh(lock);
+
+		if (tbl->rehash <= hash)
+			break;
+
+		spin_unlock_bh(lock);
+		tbl = rht_dereference_rcu(tbl->future_tbl, ht);
+	}
+
+	data = rhashtable_insert_one(ht, tbl, hash, key, obj);
+
+	while (PTR_ERR(data) == -ENOENT || PTR_ERR(data) == -EAGAIN) {
+		struct bucket_table *new_tbl;
+
+		new_tbl = rht_dereference_rcu(tbl->future_tbl, ht);
+		if (!new_tbl)
+			break;
+
+		tbl = new_tbl;
+		hash = rht_head_hashfn(ht, tbl, obj, ht->p);
+		spin_lock_nested(rht_bucket_lock(tbl, hash),
+				 SINGLE_DEPTH_NESTING);
+
+		data = rhashtable_insert_one(ht, tbl, hash, key, obj);
+
+		spin_unlock(rht_bucket_lock(tbl, hash));
 	}
 
-	err = -E2BIG;
+	if (PTR_ERR(data) != -ENOENT)
+		goto exit;
+
+	data = ERR_PTR(-E2BIG);
 	if (unlikely(rht_grow_above_max(ht, tbl)))
 		goto exit;
 
-	err = -EAGAIN;
-	if (rhashtable_check_elasticity(ht, tbl, hash) ||
-	    rht_grow_above_100(ht, tbl))
+	data = ERR_PTR(-EAGAIN);
+	if (unlikely(rht_grow_above_100(ht, tbl)))
 		goto exit;
 
-	err = 0;
+	data = NULL;
 
 	head = rht_dereference_bucket(tbl->buckets[hash], tbl, hash);
 
 	RCU_INIT_POINTER(obj->next, head);
+	if (ht->rhlist) {
+		struct rhlist_head *list;
+
+		list = container_of(obj, struct rhlist_head, rhead);
+		RCU_INIT_POINTER(list->next, NULL);
+	}
 
 	rcu_assign_pointer(tbl->buckets[hash], obj);
 
 	atomic_inc(&ht->nelems);
+	if (rht_grow_above_75(ht, tbl))
+		schedule_work(&ht->run_work);
 
 exit:
-	spin_unlock(rht_bucket_lock(tbl, hash));
+	spin_unlock_bh(lock);
 
-	if (err == 0)
-		return NULL;
-	else if (err == -EAGAIN)
-		return tbl;
-	else
-		return ERR_PTR(err);
+	if (PTR_ERR(data) == -EAGAIN)
+		data = ERR_PTR(rhashtable_insert_rehash(ht, tbl) ?:
+			       -EAGAIN);
+
+	return data;
+}
+
+void *rhashtable_insert_slow(struct rhashtable *ht, const void *key,
+			     struct rhash_head *obj)
+{
+	void *data;
+
+	do {
+		rcu_read_lock();
+		data = rhashtable_try_insert(ht, key, obj);
+		rcu_read_unlock();
+	} while (PTR_ERR(data) == -EAGAIN);
+
+	return data;
 }
 EXPORT_SYMBOL_GPL(rhashtable_insert_slow);
 
@@ -593,11 +670,16 @@ EXPORT_SYMBOL_GPL(rhashtable_walk_start);
 void *rhashtable_walk_next(struct rhashtable_iter *iter)
 {
 	struct bucket_table *tbl = iter->walker.tbl;
+	struct rhlist_head *list = iter->list;
 	struct rhashtable *ht = iter->ht;
 	struct rhash_head *p = iter->p;
+	bool rhlist = ht->rhlist;
 
 	if (p) {
-		p = rht_dereference_bucket_rcu(p->next, tbl, iter->slot);
+		if (!rhlist || !(list = rcu_dereference(list->next))) {
+			p = rcu_dereference(p->next);
+			list = container_of(p, struct rhlist_head, rhead);
+		}
 		goto next;
 	}
 
@@ -605,6 +687,18 @@ void *rhashtable_walk_next(struct rhashtable_iter *iter)
 		int skip = iter->skip;
 
 		rht_for_each_rcu(p, tbl, iter->slot) {
+			if (rhlist) {
+				list = container_of(p, struct rhlist_head,
+						    rhead);
+				do {
+					if (!skip)
+						goto next;
+					skip--;
+					list = rcu_dereference(list->next);
+				} while (list);
+
+				continue;
+			}
 			if (!skip)
 				break;
 			skip--;
@@ -614,7 +708,8 @@ next:
 		if (!rht_is_a_nulls(p)) {
 			iter->skip++;
 			iter->p = p;
-			return rht_obj(ht, p);
+			iter->list = list;
+			return rht_obj(ht, rhlist ? &list->rhead : p);
 		}
 
 		iter->skip = 0;
@@ -803,6 +898,48 @@ int rhashtable_init(struct rhashtable *ht,
 EXPORT_SYMBOL_GPL(rhashtable_init);
 
 /**
+ * rhltable_init - initialize a new hash list table
+ * @hlt:	hash list table to be initialized
+ * @params:	configuration parameters
+ *
+ * Initializes a new hash list table.
+ *
+ * See documentation for rhashtable_init.
+ */
+int rhltable_init(struct rhltable *hlt, const struct rhashtable_params *params)
+{
+	int err;
+
+	/* No rhlist NULLs marking for now. */
+	if (params->nulls_base)
+		return -EINVAL;
+
+	err = rhashtable_init(&hlt->ht, params);
+	hlt->ht.rhlist = true;
+	return err;
+}
+EXPORT_SYMBOL_GPL(rhltable_init);
+
+static void rhashtable_free_one(struct rhashtable *ht, struct rhash_head *obj,
+				void (*free_fn)(void *ptr, void *arg),
+				void *arg)
+{
+	struct rhlist_head *list;
+
+	if (!ht->rhlist) {
+		free_fn(rht_obj(ht, obj), arg);
+		return;
+	}
+
+	list = container_of(obj, struct rhlist_head, rhead);
+	do {
+		obj = &list->rhead;
+		list = rht_dereference(list->next, ht);
+		free_fn(rht_obj(ht, obj), arg);
+	} while (list);
+}
+
+/**
  * rhashtable_free_and_destroy - free elements and destroy hash table
  * @ht:		the hash table to destroy
  * @free_fn:	callback to release resources of element
@@ -839,7 +976,7 @@ void rhashtable_free_and_destroy(struct rhashtable *ht,
 			     pos = next,
 			     next = !rht_is_a_nulls(pos) ?
 					rht_dereference(pos->next, ht) : NULL)
-				free_fn(rht_obj(ht, pos), arg);
+				rhashtable_free_one(ht, pos, free_fn, arg);
 		}
 	}
 

[PATCH 2/2] mac80211: Use rhltable instead of rhashtable

[Herbert Xu]

mac80211 currently uses rhashtable with insecure_elasticity set
to true.  The latter is because of duplicate objects.  What's
more, mac80211 walks the rhashtable chains by hand which is broken
as rhashtable may contain multiple tables due to resizing or
rehashing.

This patch fixes it by converting it to the newly added rhltable
interface which is designed for use with duplicate objects.

With rhltable a lookup returns a list of objects instead of a
single one.  This is then fed into the existing for_each_sta_info
macro.

This patch also deletes the sta_addr_hash function since rhashtable
defaults to jhash.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
---

 net/mac80211/ieee80211_i.h |    2 -
 net/mac80211/rx.c          |    7 +-----
 net/mac80211/sta_info.c    |   52 ++++++++++++++++++---------------------------
 net/mac80211/sta_info.h    |   19 ++++++----------
 net/mac80211/status.c      |    7 +-----
 5 files changed, 33 insertions(+), 54 deletions(-)

diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index f56d342..1a52cd4 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -1208,7 +1208,7 @@ struct ieee80211_local {
 	spinlock_t tim_lock;
 	unsigned long num_sta;
 	struct list_head sta_list;
-	struct rhashtable sta_hash;
+	struct rhltable sta_hash;
 	struct timer_list sta_cleanup;
 	int sta_generation;
 
diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index 9dce3b1..5e26dc6 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -3940,7 +3940,7 @@ static void __ieee80211_rx_handle_packet(struct ieee80211_hw *hw,
 	__le16 fc;
 	struct ieee80211_rx_data rx;
 	struct ieee80211_sub_if_data *prev;
-	struct rhash_head *tmp;
+	struct rhlist_head *tmp;
 	int err = 0;
 
 	fc = ((struct ieee80211_hdr *)skb->data)->frame_control;
@@ -3983,13 +3983,10 @@ static void __ieee80211_rx_handle_packet(struct ieee80211_hw *hw,
 		goto out;
 	} else if (ieee80211_is_data(fc)) {
 		struct sta_info *sta, *prev_sta;
-		const struct bucket_table *tbl;
 
 		prev_sta = NULL;
 
-		tbl = rht_dereference_rcu(local->sta_hash.tbl, &local->sta_hash);
-
-		for_each_sta_info(local, tbl, hdr->addr2, sta, tmp) {
+		for_each_sta_info(local, hdr->addr2, sta, tmp) {
 			if (!prev_sta) {
 				prev_sta = sta;
 				continue;
diff --git a/net/mac80211/sta_info.c b/net/mac80211/sta_info.c
index 19f14c9..198d0bd 100644
--- a/net/mac80211/sta_info.c
+++ b/net/mac80211/sta_info.c
@@ -67,12 +67,10 @@
 
 static const struct rhashtable_params sta_rht_params = {
 	.nelem_hint = 3, /* start small */
-	.insecure_elasticity = true, /* Disable chain-length checks. */
 	.automatic_shrinking = true,
 	.head_offset = offsetof(struct sta_info, hash_node),
 	.key_offset = offsetof(struct sta_info, addr),
 	.key_len = ETH_ALEN,
-	.hashfn = sta_addr_hash,
 	.max_size = CONFIG_MAC80211_STA_HASH_MAX_SIZE,
 };
 
@@ -80,8 +78,8 @@ static const struct rhashtable_params sta_rht_params = {
 static int sta_info_hash_del(struct ieee80211_local *local,
 			     struct sta_info *sta)
 {
-	return rhashtable_remove_fast(&local->sta_hash, &sta->hash_node,
-				      sta_rht_params);
+	return rhltable_remove(&local->sta_hash, &sta->hash_node,
+			       sta_rht_params);
 }
 
 static void __cleanup_single_sta(struct sta_info *sta)
@@ -157,19 +155,22 @@ static void cleanup_single_sta(struct sta_info *sta)
 	sta_info_free(local, sta);
 }
 
+struct rhlist_head *sta_info_hash_lookup(struct ieee80211_local *local,
+					 const u8 *addr)
+{
+	return rhltable_lookup(&local->sta_hash, addr, sta_rht_params);
+}
+
 /* protected by RCU */
 struct sta_info *sta_info_get(struct ieee80211_sub_if_data *sdata,
 			      const u8 *addr)
 {
 	struct ieee80211_local *local = sdata->local;
+	struct rhlist_head *tmp;
 	struct sta_info *sta;
-	struct rhash_head *tmp;
-	const struct bucket_table *tbl;
 
 	rcu_read_lock();
-	tbl = rht_dereference_rcu(local->sta_hash.tbl, &local->sta_hash);
-
-	for_each_sta_info(local, tbl, addr, sta, tmp) {
+	for_each_sta_info(local, addr, sta, tmp) {
 		if (sta->sdata == sdata) {
 			rcu_read_unlock();
 			/* this is safe as the caller must already hold
@@ -190,14 +191,11 @@ struct sta_info *sta_info_get_bss(struct ieee80211_sub_if_data *sdata,
 				  const u8 *addr)
 {
 	struct ieee80211_local *local = sdata->local;
+	struct rhlist_head *tmp;
 	struct sta_info *sta;
-	struct rhash_head *tmp;
-	const struct bucket_table *tbl;
 
 	rcu_read_lock();
-	tbl = rht_dereference_rcu(local->sta_hash.tbl, &local->sta_hash);
-
-	for_each_sta_info(local, tbl, addr, sta, tmp) {
+	for_each_sta_info(local, addr, sta, tmp) {
 		if (sta->sdata == sdata ||
 		    (sta->sdata->bss && sta->sdata->bss == sdata->bss)) {
 			rcu_read_unlock();
@@ -263,8 +261,8 @@ void sta_info_free(struct ieee80211_local *local, struct sta_info *sta)
 static int sta_info_hash_add(struct ieee80211_local *local,
 			     struct sta_info *sta)
 {
-	return rhashtable_insert_fast(&local->sta_hash, &sta->hash_node,
-				      sta_rht_params);
+	return rhltable_insert(&local->sta_hash, &sta->hash_node,
+			       sta_rht_params);
 }
 
 static void sta_deliver_ps_frames(struct work_struct *wk)
@@ -450,9 +448,9 @@ static int sta_info_insert_check(struct sta_info *sta)
 		    is_multicast_ether_addr(sta->sta.addr)))
 		return -EINVAL;
 
-	/* Strictly speaking this isn't necessary as we hold the mutex, but
-	 * the rhashtable code can't really deal with that distinction. We
-	 * do require the mutex for correctness though.
+	/* The RCU read lock is required by rhashtable due to
+	 * asynchronous resize/rehash.  We also require the mutex
+	 * for correctness.
 	 */
 	rcu_read_lock();
 	lockdep_assert_held(&sdata->local->sta_mtx);
@@ -1040,16 +1038,11 @@ static void sta_info_cleanup(unsigned long data)
 		  round_jiffies(jiffies + STA_INFO_CLEANUP_INTERVAL));
 }
 
-u32 sta_addr_hash(const void *key, u32 length, u32 seed)
-{
-	return jhash(key, ETH_ALEN, seed);
-}
-
 int sta_info_init(struct ieee80211_local *local)
 {
 	int err;
 
-	err = rhashtable_init(&local->sta_hash, &sta_rht_params);
+	err = rhltable_init(&local->sta_hash, &sta_rht_params);
 	if (err)
 		return err;
 
@@ -1065,7 +1058,7 @@ int sta_info_init(struct ieee80211_local *local)
 void sta_info_stop(struct ieee80211_local *local)
 {
 	del_timer_sync(&local->sta_cleanup);
-	rhashtable_destroy(&local->sta_hash);
+	rhltable_destroy(&local->sta_hash);
 }
 
 
@@ -1135,17 +1128,14 @@ struct ieee80211_sta *ieee80211_find_sta_by_ifaddr(struct ieee80211_hw *hw,
 						   const u8 *localaddr)
 {
 	struct ieee80211_local *local = hw_to_local(hw);
+	struct rhlist_head *tmp;
 	struct sta_info *sta;
-	struct rhash_head *tmp;
-	const struct bucket_table *tbl;
-
-	tbl = rht_dereference_rcu(local->sta_hash.tbl, &local->sta_hash);
 
 	/*
 	 * Just return a random station if localaddr is NULL
 	 * ... first in list.
 	 */
-	for_each_sta_info(local, tbl, addr, sta, tmp) {
+	for_each_sta_info(local, addr, sta, tmp) {
 		if (localaddr &&
 		    !ether_addr_equal(sta->sdata->vif.addr, localaddr))
 			continue;
diff --git a/net/mac80211/sta_info.h b/net/mac80211/sta_info.h
index 0556be3..d347ab5 100644
--- a/net/mac80211/sta_info.h
+++ b/net/mac80211/sta_info.h
@@ -452,7 +452,7 @@ struct sta_info {
 	/* General information, mostly static */
 	struct list_head list, free_list;
 	struct rcu_head rcu_head;
-	struct rhash_head hash_node;
+	struct rhlist_head hash_node;
 	u8 addr[ETH_ALEN];
 	struct ieee80211_local *local;
 	struct ieee80211_sub_if_data *sdata;
@@ -635,6 +635,9 @@ rcu_dereference_protected_tid_tx(struct sta_info *sta, int tid)
  */
 #define STA_INFO_CLEANUP_INTERVAL (10 * HZ)
 
+struct rhlist_head *sta_info_hash_lookup(struct ieee80211_local *local,
+					 const u8 *addr);
+
 /*
  * Get a STA info, must be under RCU read lock.
  */
@@ -644,17 +647,9 @@ struct sta_info *sta_info_get(struct ieee80211_sub_if_data *sdata,
 struct sta_info *sta_info_get_bss(struct ieee80211_sub_if_data *sdata,
 				  const u8 *addr);
 
-u32 sta_addr_hash(const void *key, u32 length, u32 seed);
-
-#define _sta_bucket_idx(_tbl, _a)					\
-	rht_bucket_index(_tbl, sta_addr_hash(_a, ETH_ALEN, (_tbl)->hash_rnd))
-
-#define for_each_sta_info(local, tbl, _addr, _sta, _tmp)		\
-	rht_for_each_entry_rcu(_sta, _tmp, tbl, 			\
-			       _sta_bucket_idx(tbl, _addr),		\
-			       hash_node)				\
-	/* compare address and run code only if it matches */		\
-	if (ether_addr_equal(_sta->addr, (_addr)))
+#define for_each_sta_info(local, _addr, _sta, _tmp)			\
+	rhl_for_each_entry_rcu(_sta, _tmp,				\
+			       sta_info_hash_lookup(local, _addr), hash_node)
 
 /*
  * Get STA info by index, BROKEN!
diff --git a/net/mac80211/status.c b/net/mac80211/status.c
index a2a6826..6361709 100644
--- a/net/mac80211/status.c
+++ b/net/mac80211/status.c
@@ -740,8 +740,8 @@ void ieee80211_tx_status(struct ieee80211_hw *hw, struct sk_buff *skb)
 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 	__le16 fc;
 	struct ieee80211_supported_band *sband;
+	struct rhlist_head *tmp;
 	struct sta_info *sta;
-	struct rhash_head *tmp;
 	int retry_count;
 	int rates_idx;
 	bool send_to_cooked;
@@ -749,7 +749,6 @@ void ieee80211_tx_status(struct ieee80211_hw *hw, struct sk_buff *skb)
 	struct ieee80211_bar *bar;
 	int shift = 0;
 	int tid = IEEE80211_NUM_TIDS;
-	const struct bucket_table *tbl;
 
 	rates_idx = ieee80211_tx_get_rates(hw, info, &retry_count);
 
@@ -758,9 +757,7 @@ void ieee80211_tx_status(struct ieee80211_hw *hw, struct sk_buff *skb)
 	sband = local->hw.wiphy->bands[info->band];
 	fc = hdr->frame_control;
 
-	tbl = rht_dereference_rcu(local->sta_hash.tbl, &local->sta_hash);
-
-	for_each_sta_info(local, tbl, hdr->addr1, sta, tmp) {
+	for_each_sta_info(local, hdr->addr1, sta, tmp) {
 		/* skip wrong virtual interface */
 		if (!ether_addr_equal(hdr->addr2, sta->sdata->vif.addr))
 			continue;

[PATCH 2/2] mac80211: Use rhltable instead of rhashtable

[Herbert Xu]

mac80211 currently uses rhashtable with insecure_elasticity set
to true.  The latter is because of duplicate objects.  What's
more, mac80211 walks the rhashtable chains by hand which is broken
as rhashtable may contain multiple tables due to resizing or
rehashing.

This patch fixes it by converting it to the newly added rhltable
interface which is designed for use with duplicate objects.

With rhltable a lookup returns a list of objects instead of a
single one.  This is then fed into the existing for_each_sta_info
macro.

This patch also deletes the sta_addr_hash function since rhashtable
defaults to jhash.

Signed-off-by: Herbert Xu <herbert-lOAM2aK0SrRLBo1qDEOMRrpzq4S04n8Q@public.gmane.org>
---

 net/mac80211/ieee80211_i.h |    2 -
 net/mac80211/rx.c          |    7 +-----
 net/mac80211/sta_info.c    |   52 ++++++++++++++++++---------------------------
 net/mac80211/sta_info.h    |   19 ++++++----------
 net/mac80211/status.c      |    7 +-----
 5 files changed, 33 insertions(+), 54 deletions(-)

diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index f56d342..1a52cd4 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -1208,7 +1208,7 @@ struct ieee80211_local {
 	spinlock_t tim_lock;
 	unsigned long num_sta;
 	struct list_head sta_list;
-	struct rhashtable sta_hash;
+	struct rhltable sta_hash;
 	struct timer_list sta_cleanup;
 	int sta_generation;
 
diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index 9dce3b1..5e26dc6 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -3940,7 +3940,7 @@ static void __ieee80211_rx_handle_packet(struct ieee80211_hw *hw,
 	__le16 fc;
 	struct ieee80211_rx_data rx;
 	struct ieee80211_sub_if_data *prev;
-	struct rhash_head *tmp;
+	struct rhlist_head *tmp;
 	int err = 0;
 
 	fc = ((struct ieee80211_hdr *)skb->data)->frame_control;
@@ -3983,13 +3983,10 @@ static void __ieee80211_rx_handle_packet(struct ieee80211_hw *hw,
 		goto out;
 	} else if (ieee80211_is_data(fc)) {
 		struct sta_info *sta, *prev_sta;
-		const struct bucket_table *tbl;
 
 		prev_sta = NULL;
 
-		tbl = rht_dereference_rcu(local->sta_hash.tbl, &local->sta_hash);
-
-		for_each_sta_info(local, tbl, hdr->addr2, sta, tmp) {
+		for_each_sta_info(local, hdr->addr2, sta, tmp) {
 			if (!prev_sta) {
 				prev_sta = sta;
 				continue;
diff --git a/net/mac80211/sta_info.c b/net/mac80211/sta_info.c
index 19f14c9..198d0bd 100644
--- a/net/mac80211/sta_info.c
+++ b/net/mac80211/sta_info.c
@@ -67,12 +67,10 @@
 
 static const struct rhashtable_params sta_rht_params = {
 	.nelem_hint = 3, /* start small */
-	.insecure_elasticity = true, /* Disable chain-length checks. */
 	.automatic_shrinking = true,
 	.head_offset = offsetof(struct sta_info, hash_node),
 	.key_offset = offsetof(struct sta_info, addr),
 	.key_len = ETH_ALEN,
-	.hashfn = sta_addr_hash,
 	.max_size = CONFIG_MAC80211_STA_HASH_MAX_SIZE,
 };
 
@@ -80,8 +78,8 @@ static const struct rhashtable_params sta_rht_params = {
 static int sta_info_hash_del(struct ieee80211_local *local,
 			     struct sta_info *sta)
 {
-	return rhashtable_remove_fast(&local->sta_hash, &sta->hash_node,
-				      sta_rht_params);
+	return rhltable_remove(&local->sta_hash, &sta->hash_node,
+			       sta_rht_params);
 }
 
 static void __cleanup_single_sta(struct sta_info *sta)
@@ -157,19 +155,22 @@ static void cleanup_single_sta(struct sta_info *sta)
 	sta_info_free(local, sta);
 }
 
+struct rhlist_head *sta_info_hash_lookup(struct ieee80211_local *local,
+					 const u8 *addr)
+{
+	return rhltable_lookup(&local->sta_hash, addr, sta_rht_params);
+}
+
 /* protected by RCU */
 struct sta_info *sta_info_get(struct ieee80211_sub_if_data *sdata,
 			      const u8 *addr)
 {
 	struct ieee80211_local *local = sdata->local;
+	struct rhlist_head *tmp;
 	struct sta_info *sta;
-	struct rhash_head *tmp;
-	const struct bucket_table *tbl;
 
 	rcu_read_lock();
-	tbl = rht_dereference_rcu(local->sta_hash.tbl, &local->sta_hash);
-
-	for_each_sta_info(local, tbl, addr, sta, tmp) {
+	for_each_sta_info(local, addr, sta, tmp) {
 		if (sta->sdata == sdata) {
 			rcu_read_unlock();
 			/* this is safe as the caller must already hold
@@ -190,14 +191,11 @@ struct sta_info *sta_info_get_bss(struct ieee80211_sub_if_data *sdata,
 				  const u8 *addr)
 {
 	struct ieee80211_local *local = sdata->local;
+	struct rhlist_head *tmp;
 	struct sta_info *sta;
-	struct rhash_head *tmp;
-	const struct bucket_table *tbl;
 
 	rcu_read_lock();
-	tbl = rht_dereference_rcu(local->sta_hash.tbl, &local->sta_hash);
-
-	for_each_sta_info(local, tbl, addr, sta, tmp) {
+	for_each_sta_info(local, addr, sta, tmp) {
 		if (sta->sdata == sdata ||
 		    (sta->sdata->bss && sta->sdata->bss == sdata->bss)) {
 			rcu_read_unlock();
@@ -263,8 +261,8 @@ void sta_info_free(struct ieee80211_local *local, struct sta_info *sta)
 static int sta_info_hash_add(struct ieee80211_local *local,
 			     struct sta_info *sta)
 {
-	return rhashtable_insert_fast(&local->sta_hash, &sta->hash_node,
-				      sta_rht_params);
+	return rhltable_insert(&local->sta_hash, &sta->hash_node,
+			       sta_rht_params);
 }
 
 static void sta_deliver_ps_frames(struct work_struct *wk)
@@ -450,9 +448,9 @@ static int sta_info_insert_check(struct sta_info *sta)
 		    is_multicast_ether_addr(sta->sta.addr)))
 		return -EINVAL;
 
-	/* Strictly speaking this isn't necessary as we hold the mutex, but
-	 * the rhashtable code can't really deal with that distinction. We
-	 * do require the mutex for correctness though.
+	/* The RCU read lock is required by rhashtable due to
+	 * asynchronous resize/rehash.  We also require the mutex
+	 * for correctness.
 	 */
 	rcu_read_lock();
 	lockdep_assert_held(&sdata->local->sta_mtx);
@@ -1040,16 +1038,11 @@ static void sta_info_cleanup(unsigned long data)
 		  round_jiffies(jiffies + STA_INFO_CLEANUP_INTERVAL));
 }
 
-u32 sta_addr_hash(const void *key, u32 length, u32 seed)
-{
-	return jhash(key, ETH_ALEN, seed);
-}
-
 int sta_info_init(struct ieee80211_local *local)
 {
 	int err;
 
-	err = rhashtable_init(&local->sta_hash, &sta_rht_params);
+	err = rhltable_init(&local->sta_hash, &sta_rht_params);
 	if (err)
 		return err;
 
@@ -1065,7 +1058,7 @@ int sta_info_init(struct ieee80211_local *local)
 void sta_info_stop(struct ieee80211_local *local)
 {
 	del_timer_sync(&local->sta_cleanup);
-	rhashtable_destroy(&local->sta_hash);
+	rhltable_destroy(&local->sta_hash);
 }
 
 
@@ -1135,17 +1128,14 @@ struct ieee80211_sta *ieee80211_find_sta_by_ifaddr(struct ieee80211_hw *hw,
 						   const u8 *localaddr)
 {
 	struct ieee80211_local *local = hw_to_local(hw);
+	struct rhlist_head *tmp;
 	struct sta_info *sta;
-	struct rhash_head *tmp;
-	const struct bucket_table *tbl;
-
-	tbl = rht_dereference_rcu(local->sta_hash.tbl, &local->sta_hash);
 
 	/*
 	 * Just return a random station if localaddr is NULL
 	 * ... first in list.
 	 */
-	for_each_sta_info(local, tbl, addr, sta, tmp) {
+	for_each_sta_info(local, addr, sta, tmp) {
 		if (localaddr &&
 		    !ether_addr_equal(sta->sdata->vif.addr, localaddr))
 			continue;
diff --git a/net/mac80211/sta_info.h b/net/mac80211/sta_info.h
index 0556be3..d347ab5 100644
--- a/net/mac80211/sta_info.h
+++ b/net/mac80211/sta_info.h
@@ -452,7 +452,7 @@ struct sta_info {
 	/* General information, mostly static */
 	struct list_head list, free_list;
 	struct rcu_head rcu_head;
-	struct rhash_head hash_node;
+	struct rhlist_head hash_node;
 	u8 addr[ETH_ALEN];
 	struct ieee80211_local *local;
 	struct ieee80211_sub_if_data *sdata;
@@ -635,6 +635,9 @@ rcu_dereference_protected_tid_tx(struct sta_info *sta, int tid)
  */
 #define STA_INFO_CLEANUP_INTERVAL (10 * HZ)
 
+struct rhlist_head *sta_info_hash_lookup(struct ieee80211_local *local,
+					 const u8 *addr);
+
 /*
  * Get a STA info, must be under RCU read lock.
  */
@@ -644,17 +647,9 @@ struct sta_info *sta_info_get(struct ieee80211_sub_if_data *sdata,
 struct sta_info *sta_info_get_bss(struct ieee80211_sub_if_data *sdata,
 				  const u8 *addr);
 
-u32 sta_addr_hash(const void *key, u32 length, u32 seed);
-
-#define _sta_bucket_idx(_tbl, _a)					\
-	rht_bucket_index(_tbl, sta_addr_hash(_a, ETH_ALEN, (_tbl)->hash_rnd))
-
-#define for_each_sta_info(local, tbl, _addr, _sta, _tmp)		\
-	rht_for_each_entry_rcu(_sta, _tmp, tbl, 			\
-			       _sta_bucket_idx(tbl, _addr),		\
-			       hash_node)				\
-	/* compare address and run code only if it matches */		\
-	if (ether_addr_equal(_sta->addr, (_addr)))
+#define for_each_sta_info(local, _addr, _sta, _tmp)			\
+	rhl_for_each_entry_rcu(_sta, _tmp,				\
+			       sta_info_hash_lookup(local, _addr), hash_node)
 
 /*
  * Get STA info by index, BROKEN!
diff --git a/net/mac80211/status.c b/net/mac80211/status.c
index a2a6826..6361709 100644
--- a/net/mac80211/status.c
+++ b/net/mac80211/status.c
@@ -740,8 +740,8 @@ void ieee80211_tx_status(struct ieee80211_hw *hw, struct sk_buff *skb)
 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 	__le16 fc;
 	struct ieee80211_supported_band *sband;
+	struct rhlist_head *tmp;
 	struct sta_info *sta;
-	struct rhash_head *tmp;
 	int retry_count;
 	int rates_idx;
 	bool send_to_cooked;
@@ -749,7 +749,6 @@ void ieee80211_tx_status(struct ieee80211_hw *hw, struct sk_buff *skb)
 	struct ieee80211_bar *bar;
 	int shift = 0;
 	int tid = IEEE80211_NUM_TIDS;
-	const struct bucket_table *tbl;
 
 	rates_idx = ieee80211_tx_get_rates(hw, info, &retry_count);
 
@@ -758,9 +757,7 @@ void ieee80211_tx_status(struct ieee80211_hw *hw, struct sk_buff *skb)
 	sband = local->hw.wiphy->bands[info->band];
 	fc = hdr->frame_control;
 
-	tbl = rht_dereference_rcu(local->sta_hash.tbl, &local->sta_hash);

Re: [PATCH 0/2] rhashtable: rhashtable with duplicate objects

[Johannes Berg]

> OK, it's finally ready now.
> 
> This series contains one two patches.  The first adds the rhlist
> interface and the second converts mac80211 to use it.  If this works
> out I'll then proceed to convert the other insecure_elasticity
> users over to this.

Thanks a lot Herbert!

> I've tested the rhlist code with test_rhashtable but I haven't
> tested the mac80211 conversion.  So please give it a go and see
> if it still works.

Yes, it's passing all the wpa_supplicant tests, so

Acked-by: Johannes Berg <johannes@sipsolutions.net>

I assume you want at least the first patch to be merged through net-
next so you can build on it.

Dave, I don't have anything pending right now since you just pulled, so
I can also wait for you to apply the rhltable and then merge the
mac80211 patch. If you apply the mac80211 patch directly I'll just wait
for both of them to show up and then I'll fast forward to your tree.

Thanks,
johannes

Re: [PATCH 0/2] rhashtable: rhashtable with duplicate objects

[Johannes Berg]

> Yes, it's passing all the wpa_supplicant tests, so
> 
> Acked-by: Johannes Berg <johannes@sipsolutions.net>
> 

I take that back. I think it's leaking memory - my tests never used to
run out of memory, but now they eventually do.

I'll try to figure out more.

johannes

Re: [PATCH 0/2] rhashtable: rhashtable with duplicate objects

[Herbert Xu]

On Mon, Sep 19, 2016 at 10:25:18AM +0200, Johannes Berg wrote:
> 
> > Yes, it's passing all the wpa_supplicant tests, so
> > 
> > Acked-by: Johannes Berg <johannes@sipsolutions.net>
> > 
> 
> I take that back. I think it's leaking memory - my tests never used to
> run out of memory, but now they eventually do.
> 
> I'll try to figure out more.

Interesting.  The kernel test robot found a bug in the insertion
slowpath where we end up inserting without taking the inner spinlock
in case of a nested table.  Not sure whether that's the same issue
as you're seeing but I'll do a v2 posting.

Thanks,
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

Re: [PATCH 0/2] rhashtable: rhashtable with duplicate objects

[Herbert Xu]

On Mon, Sep 19, 2016 at 10:25:18AM +0200, Johannes Berg wrote:
> 
> > Yes, it's passing all the wpa_supplicant tests, so
> > 
> > Acked-by: Johannes Berg <johannes-cdvu00un1VgdHxzADdlk8Q@public.gmane.org>
> > 
> 
> I take that back. I think it's leaking memory - my tests never used to
> run out of memory, but now they eventually do.
> 
> I'll try to figure out more.

Interesting.  The kernel test robot found a bug in the insertion
slowpath where we end up inserting without taking the inner spinlock
in case of a nested table.  Not sure whether that's the same issue
as you're seeing but I'll do a v2 posting.

Thanks,
-- 
Email: Herbert Xu <herbert-lOAM2aK0SrRLBo1qDEOMRrpzq4S04n8Q@public.gmane.org>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

[v2 PATCH 0/2] rhashtable: rhashtable with duplicate objects

[Herbert Xu]

v2 contains a reworked insertion slowpath to ensure that the
spinlock for the table we're inserting into is taken.

This series contains one two patches.  The first adds the rhlist
interface and the second converts mac80211 to use it.  If this works
out I'll then proceed to convert the other insecure_elasticity
users over to this.

I've tested the rhlist code with test_rhashtable but I haven't
tested the mac80211 conversion.  So please give it a go and see
if it still works.

Thanks!
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

[v2 PATCH 1/2] rhashtable: Add rhlist interface

[Herbert Xu]

The insecure_elasticity setting is an ugly wart brought out by
users who need to insert duplicate objects (that is, distinct
objects with identical keys) into the same table.

In fact, those users have a much bigger problem.  Once those
duplicate objects are inserted, they don't have an interface to
find them (unless you count the walker interface which walks
over the entire table).

Some users have resorted to doing a manual walk over the hash
table which is of course broken because they don't handle the
potential existence of multiple hash tables.  The result is that
they will break sporadically when they encounter a hash table
resize/rehash.

This patch provides a way out for those users, at the expense
of an extra pointer per object.  Essentially each object is now
a list of objects carrying the same key.  The hash table will
only see the lists so nothing changes as far as rhashtable is
concerned.

To use this new interface, you need to insert a struct rhlist_head
into your objects instead of struct rhash_head.  While the hash
table is unchanged, for type-safety you'll need to use struct
rhltable instead of struct rhashtable.  All the existing interfaces
have been duplicated for rhlist, including the hash table walker.

One missing feature is nulls marking because AFAIK the only potential
user of it does not need duplicate objects.  Should anyone need
this it shouldn't be too hard to add.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
---

 include/linux/rhashtable.h |  490 ++++++++++++++++++++++++++++++++++-----------
 lib/rhashtable.c           |  258 ++++++++++++++++++-----
 2 files changed, 582 insertions(+), 166 deletions(-)

diff --git a/include/linux/rhashtable.h b/include/linux/rhashtable.h
index fd82584..dc7bea6 100644
--- a/include/linux/rhashtable.h
+++ b/include/linux/rhashtable.h
@@ -1,7 +1,7 @@
 /*
  * Resizable, Scalable, Concurrent Hash Table
  *
- * Copyright (c) 2015 Herbert Xu <herbert@gondor.apana.org.au>
+ * Copyright (c) 2015-2016 Herbert Xu <herbert@gondor.apana.org.au>
  * Copyright (c) 2014-2015 Thomas Graf <tgraf@suug.ch>
  * Copyright (c) 2008-2014 Patrick McHardy <kaber@trash.net>
  *
@@ -53,6 +53,11 @@ struct rhash_head {
 	struct rhash_head __rcu		*next;
 };
 
+struct rhlist_head {
+	struct rhash_head		rhead;
+	struct rhlist_head __rcu	*next;
+};
+
 /**
  * struct bucket_table - Table of hash buckets
  * @size: Number of hash buckets
@@ -137,6 +142,7 @@ struct rhashtable_params {
  * @key_len: Key length for hashfn
  * @elasticity: Maximum chain length before rehash
  * @p: Configuration parameters
+ * @rhlist: True if this is an rhltable
  * @run_work: Deferred worker to expand/shrink asynchronously
  * @mutex: Mutex to protect current/future table swapping
  * @lock: Spin lock to protect walker list
@@ -147,12 +153,21 @@ struct rhashtable {
 	unsigned int			key_len;
 	unsigned int			elasticity;
 	struct rhashtable_params	p;
+	bool				rhlist;
 	struct work_struct		run_work;
 	struct mutex                    mutex;
 	spinlock_t			lock;
 };
 
 /**
+ * struct rhltable - Hash table with duplicate objects in a list
+ * @ht: Underlying rhtable
+ */
+struct rhltable {
+	struct rhashtable ht;
+};
+
+/**
  * struct rhashtable_walker - Hash table walker
  * @list: List entry on list of walkers
  * @tbl: The table that we were walking over
@@ -163,9 +178,10 @@ struct rhashtable_walker {
 };
 
 /**
- * struct rhashtable_iter - Hash table iterator, fits into netlink cb
+ * struct rhashtable_iter - Hash table iterator
  * @ht: Table to iterate through
  * @p: Current pointer
+ * @list: Current hash list pointer
  * @walker: Associated rhashtable walker
  * @slot: Current slot
  * @skip: Number of entries to skip in slot
@@ -173,6 +189,7 @@ struct rhashtable_walker {
 struct rhashtable_iter {
 	struct rhashtable *ht;
 	struct rhash_head *p;
+	struct rhlist_head *list;
 	struct rhashtable_walker walker;
 	unsigned int slot;
 	unsigned int skip;
@@ -339,13 +356,11 @@ static inline int lockdep_rht_bucket_is_held(const struct bucket_table *tbl,
 
 int rhashtable_init(struct rhashtable *ht,
 		    const struct rhashtable_params *params);
+int rhltable_init(struct rhltable *hlt,
+		  const struct rhashtable_params *params);
 
-struct bucket_table *rhashtable_insert_slow(struct rhashtable *ht,
-					    const void *key,
-					    struct rhash_head *obj,
-					    struct bucket_table *old_tbl,
-					    void **data);
-int rhashtable_insert_rehash(struct rhashtable *ht, struct bucket_table *tbl);
+void *rhashtable_insert_slow(struct rhashtable *ht, const void *key,
+			     struct rhash_head *obj);
 
 void rhashtable_walk_enter(struct rhashtable *ht,
 			   struct rhashtable_iter *iter);
@@ -507,6 +522,31 @@ void rhashtable_destroy(struct rhashtable *ht);
 	rht_for_each_entry_rcu_continue(tpos, pos, (tbl)->buckets[hash],\
 					tbl, hash, member)
 
+/**
+ * rhl_for_each_rcu - iterate over rcu hash table list
+ * @pos:	the &struct rlist_head to use as a loop cursor.
+ * @list:	the head of the list
+ *
+ * This hash chain list-traversal primitive should be used on the
+ * list returned by rhltable_lookup.
+ */
+#define rhl_for_each_rcu(pos, list)					\
+	for (pos = list; pos; pos = rcu_dereference_raw(pos->next))
+
+/**
+ * rhl_for_each_entry_rcu - iterate over rcu hash table list of given type
+ * @tpos:	the type * to use as a loop cursor.
+ * @pos:	the &struct rlist_head to use as a loop cursor.
+ * @list:	the head of the list
+ * @member:	name of the &struct rlist_head within the hashable struct.
+ *
+ * This hash chain list-traversal primitive should be used on the
+ * list returned by rhltable_lookup.
+ */
+#define rhl_for_each_entry_rcu(tpos, pos, list, member)			\
+	for (pos = list; pos && rht_entry(tpos, pos, member);		\
+	     pos = rcu_dereference_raw(pos->next))
+
 static inline int rhashtable_compare(struct rhashtable_compare_arg *arg,
 				     const void *obj)
 {
@@ -516,18 +556,8 @@ static inline int rhashtable_compare(struct rhashtable_compare_arg *arg,
 	return memcmp(ptr + ht->p.key_offset, arg->key, ht->p.key_len);
 }
 
-/**
- * rhashtable_lookup_fast - search hash table, inlined version
- * @ht:		hash table
- * @key:	the pointer to the key
- * @params:	hash table parameters
- *
- * Computes the hash value for the key and traverses the bucket chain looking
- * for a entry with an identical key. The first matching entry is returned.
- *
- * Returns the first entry on which the compare function returned true.
- */
-static inline void *rhashtable_lookup_fast(
+/* Internal function, do not use. */
+static inline struct rhash_head *__rhashtable_lookup(
 	struct rhashtable *ht, const void *key,
 	const struct rhashtable_params params)
 {
@@ -539,8 +569,6 @@ static inline void *rhashtable_lookup_fast(
 	struct rhash_head *he;
 	unsigned int hash;
 
-	rcu_read_lock();
-
 	tbl = rht_dereference_rcu(ht->tbl, ht);
 restart:
 	hash = rht_key_hashfn(ht, tbl, key, params);
@@ -549,8 +577,7 @@ restart:
 		    params.obj_cmpfn(&arg, rht_obj(ht, he)) :
 		    rhashtable_compare(&arg, rht_obj(ht, he)))
 			continue;
-		rcu_read_unlock();
-		return rht_obj(ht, he);
+		return he;
 	}
 
 	/* Ensure we see any new tables. */
@@ -559,96 +586,165 @@ restart:
 	tbl = rht_dereference_rcu(tbl->future_tbl, ht);
 	if (unlikely(tbl))
 		goto restart;
-	rcu_read_unlock();
 
 	return NULL;
 }
 
+/**
+ * rhashtable_lookup - search hash table
+ * @ht:		hash table
+ * @key:	the pointer to the key
+ * @params:	hash table parameters
+ *
+ * Computes the hash value for the key and traverses the bucket chain looking
+ * for a entry with an identical key. The first matching entry is returned.
+ *
+ * This must only be called under the RCU read lock.
+ *
+ * Returns the first entry on which the compare function returned true.
+ */
+static inline void *rhashtable_lookup(
+	struct rhashtable *ht, const void *key,
+	const struct rhashtable_params params)
+{
+	struct rhash_head *he = __rhashtable_lookup(ht, key, params);
+
+	return he ? rht_obj(ht, he) : NULL;
+}
+
+/**
+ * rhashtable_lookup_fast - search hash table, without RCU read lock
+ * @ht:		hash table
+ * @key:	the pointer to the key
+ * @params:	hash table parameters
+ *
+ * Computes the hash value for the key and traverses the bucket chain looking
+ * for a entry with an identical key. The first matching entry is returned.
+ *
+ * Only use this function when you have other mechanisms guaranteeing
+ * that the object won't go away after the RCU read lock is released.
+ *
+ * Returns the first entry on which the compare function returned true.
+ */
+static inline void *rhashtable_lookup_fast(
+	struct rhashtable *ht, const void *key,
+	const struct rhashtable_params params)
+{
+	void *obj;
+
+	rcu_read_lock();
+	obj = rhashtable_lookup(ht, key, params);
+	rcu_read_unlock();
+
+	return obj;
+}
+
+/**
+ * rhltable_lookup - search hash list table
+ * @hlt:	hash table
+ * @key:	the pointer to the key
+ * @params:	hash table parameters
+ *
+ * Computes the hash value for the key and traverses the bucket chain looking
+ * for a entry with an identical key.  All matching entries are returned
+ * in a list.
+ *
+ * This must only be called under the RCU read lock.
+ *
+ * Returns the list of entries that match the given key.
+ */
+static inline struct rhlist_head *rhltable_lookup(
+	struct rhltable *hlt, const void *key,
+	const struct rhashtable_params params)
+{
+	struct rhash_head *he = __rhashtable_lookup(&hlt->ht, key, params);
+
+	return he ? container_of(he, struct rhlist_head, rhead) : NULL;
+}
+
 /* Internal function, please use rhashtable_insert_fast() instead. This
  * function returns the existing element already in hashes in there is a clash,
  * otherwise it returns an error via ERR_PTR().
  */
 static inline void *__rhashtable_insert_fast(
 	struct rhashtable *ht, const void *key, struct rhash_head *obj,
-	const struct rhashtable_params params)
+	const struct rhashtable_params params, bool rhlist)
 {
 	struct rhashtable_compare_arg arg = {
 		.ht = ht,
 		.key = key,
 	};
-	struct bucket_table *tbl, *new_tbl;
+	struct rhash_head __rcu **pprev;
+	struct bucket_table *tbl;
 	struct rhash_head *head;
 	spinlock_t *lock;
-	unsigned int elasticity;
 	unsigned int hash;
-	void *data = NULL;
-	int err;
+	int elasticity;
+	void *data;
 
-restart:
 	rcu_read_lock();
 
 	tbl = rht_dereference_rcu(ht->tbl, ht);
+	hash = rht_head_hashfn(ht, tbl, obj, params);
+	lock = rht_bucket_lock(tbl, hash);
+	spin_lock_bh(lock);
 
-	/* All insertions must grab the oldest table containing
-	 * the hashed bucket that is yet to be rehashed.
-	 */
-	for (;;) {
-		hash = rht_head_hashfn(ht, tbl, obj, params);
-		lock = rht_bucket_lock(tbl, hash);
-		spin_lock_bh(lock);
-
-		if (tbl->rehash <= hash)
-			break;
-
+	if (unlikely(rht_dereference_bucket(tbl->future_tbl, tbl, hash))) {
+slow_path:
 		spin_unlock_bh(lock);
-		tbl = rht_dereference_rcu(tbl->future_tbl, ht);
+		rcu_read_unlock();
+		return rhashtable_insert_slow(ht, key, obj);
 	}
 
-	new_tbl = rht_dereference_rcu(tbl->future_tbl, ht);
-	if (unlikely(new_tbl)) {
-		tbl = rhashtable_insert_slow(ht, key, obj, new_tbl, &data);
-		if (!IS_ERR_OR_NULL(tbl))
-			goto slow_path;
+	elasticity = ht->elasticity;
+	pprev = &tbl->buckets[hash];
+	rht_for_each(head, tbl, hash) {
+		struct rhlist_head *plist;
+		struct rhlist_head *list;
+
+		elasticity--;
+		if (!key ||
+		    (params.obj_cmpfn ?
+		     params.obj_cmpfn(&arg, rht_obj(ht, head)) :
+		     rhashtable_compare(&arg, rht_obj(ht, head))))
+			continue;
+
+		data = rht_obj(ht, head);
 
-		err = PTR_ERR(tbl);
-		if (err == -EEXIST)
-			err = 0;
+		if (!rhlist)
+			goto out;
 
-		goto out;
-	}
 
-	err = -E2BIG;
-	if (unlikely(rht_grow_above_max(ht, tbl)))
-		goto out;
+		list = container_of(obj, struct rhlist_head, rhead);
+		plist = container_of(head, struct rhlist_head, rhead);
 
-	if (unlikely(rht_grow_above_100(ht, tbl))) {
-slow_path:
-		spin_unlock_bh(lock);
-		err = rhashtable_insert_rehash(ht, tbl);
-		rcu_read_unlock();
-		if (err)
-			return ERR_PTR(err);
+		RCU_INIT_POINTER(list->next, plist);
+		head = rht_dereference_bucket(head->next, tbl, hash);
+		RCU_INIT_POINTER(list->rhead.next, head);
+		rcu_assign_pointer(*pprev, obj);
 
-		goto restart;
+		goto good;
 	}
 
-	err = 0;
-	elasticity = ht->elasticity;
-	rht_for_each(head, tbl, hash) {
-		if (key &&
-		    unlikely(!(params.obj_cmpfn ?
-			       params.obj_cmpfn(&arg, rht_obj(ht, head)) :
-			       rhashtable_compare(&arg, rht_obj(ht, head))))) {
-			data = rht_obj(ht, head);
-			goto out;
-		}
-		if (!--elasticity)
-			goto slow_path;
-	}
+	if (elasticity <= 0)
+		goto slow_path;
+
+	data = ERR_PTR(-E2BIG);
+	if (unlikely(rht_grow_above_max(ht, tbl)))
+		goto out;
+
+	if (unlikely(rht_grow_above_100(ht, tbl)))
+		goto slow_path;
 
 	head = rht_dereference_bucket(tbl->buckets[hash], tbl, hash);
 
 	RCU_INIT_POINTER(obj->next, head);
+	if (rhlist) {
+		struct rhlist_head *list;
+
+		list = container_of(obj, struct rhlist_head, rhead);
+		RCU_INIT_POINTER(list->next, NULL);
+	}
 
 	rcu_assign_pointer(tbl->buckets[hash], obj);
 
@@ -656,11 +752,14 @@ slow_path:
 	if (rht_grow_above_75(ht, tbl))
 		schedule_work(&ht->run_work);
 
+good:
+	data = NULL;
+
 out:
 	spin_unlock_bh(lock);
 	rcu_read_unlock();
 
-	return err ? ERR_PTR(err) : data;
+	return data;
 }
 
 /**
@@ -685,7 +784,7 @@ static inline int rhashtable_insert_fast(
 {
 	void *ret;
 
-	ret = __rhashtable_insert_fast(ht, NULL, obj, params);
+	ret = __rhashtable_insert_fast(ht, NULL, obj, params, false);
 	if (IS_ERR(ret))
 		return PTR_ERR(ret);
 
@@ -693,6 +792,58 @@ static inline int rhashtable_insert_fast(
 }
 
 /**
+ * rhltable_insert_key - insert object into hash list table
+ * @hlt:	hash list table
+ * @key:	the pointer to the key
+ * @list:	pointer to hash list head inside object
+ * @params:	hash table parameters
+ *
+ * Will take a per bucket spinlock to protect against mutual mutations
+ * on the same bucket. Multiple insertions may occur in parallel unless
+ * they map to the same bucket lock.
+ *
+ * It is safe to call this function from atomic context.
+ *
+ * Will trigger an automatic deferred table resizing if the size grows
+ * beyond the watermark indicated by grow_decision() which can be passed
+ * to rhashtable_init().
+ */
+static inline int rhltable_insert_key(
+	struct rhltable *hlt, const void *key, struct rhlist_head *list,
+	const struct rhashtable_params params)
+{
+	return PTR_ERR(__rhashtable_insert_fast(&hlt->ht, key, &list->rhead,
+						params, true));
+}
+
+/**
+ * rhltable_insert - insert object into hash list table
+ * @hlt:	hash list table
+ * @list:	pointer to hash list head inside object
+ * @params:	hash table parameters
+ *
+ * Will take a per bucket spinlock to protect against mutual mutations
+ * on the same bucket. Multiple insertions may occur in parallel unless
+ * they map to the same bucket lock.
+ *
+ * It is safe to call this function from atomic context.
+ *
+ * Will trigger an automatic deferred table resizing if the size grows
+ * beyond the watermark indicated by grow_decision() which can be passed
+ * to rhashtable_init().
+ */
+static inline int rhltable_insert(
+	struct rhltable *hlt, struct rhlist_head *list,
+	const struct rhashtable_params params)
+{
+	const char *key = rht_obj(&hlt->ht, &list->rhead);
+
+	key += params.key_offset;
+
+	return rhltable_insert_key(hlt, key, list, params);
+}
+
+/**
  * rhashtable_lookup_insert_fast - lookup and insert object into hash table
  * @ht:		hash table
  * @obj:	pointer to hash head inside object
@@ -722,7 +873,8 @@ static inline int rhashtable_lookup_insert_fast(
 
 	BUG_ON(ht->p.obj_hashfn);
 
-	ret = __rhashtable_insert_fast(ht, key + ht->p.key_offset, obj, params);
+	ret = __rhashtable_insert_fast(ht, key + ht->p.key_offset, obj, params,
+				       false);
 	if (IS_ERR(ret))
 		return PTR_ERR(ret);
 
@@ -759,7 +911,7 @@ static inline int rhashtable_lookup_insert_key(
 
 	BUG_ON(!ht->p.obj_hashfn || !key);
 
-	ret = __rhashtable_insert_fast(ht, key, obj, params);
+	ret = __rhashtable_insert_fast(ht, key, obj, params, false);
 	if (IS_ERR(ret))
 		return PTR_ERR(ret);
 
@@ -783,13 +935,14 @@ static inline void *rhashtable_lookup_get_insert_key(
 {
 	BUG_ON(!ht->p.obj_hashfn || !key);
 
-	return __rhashtable_insert_fast(ht, key, obj, params);
+	return __rhashtable_insert_fast(ht, key, obj, params, false);
 }
 
 /* Internal function, please use rhashtable_remove_fast() instead */
-static inline int __rhashtable_remove_fast(
+static inline int __rhashtable_remove_fast_one(
 	struct rhashtable *ht, struct bucket_table *tbl,
-	struct rhash_head *obj, const struct rhashtable_params params)
+	struct rhash_head *obj, const struct rhashtable_params params,
+	bool rhlist)
 {
 	struct rhash_head __rcu **pprev;
 	struct rhash_head *he;
@@ -804,39 +957,65 @@ static inline int __rhashtable_remove_fast(
 
 	pprev = &tbl->buckets[hash];
 	rht_for_each(he, tbl, hash) {
+		struct rhlist_head *list;
+
+		list = container_of(he, struct rhlist_head, rhead);
+
 		if (he != obj) {
+			struct rhlist_head __rcu **lpprev;
+
 			pprev = &he->next;
-			continue;
+
+			if (!rhlist)
+				continue;
+
+			do {
+				lpprev = &list->next;
+				list = rht_dereference_bucket(list->next,
+							      tbl, hash);
+			} while (list && obj != &list->rhead);
+
+			if (!list)
+				continue;
+
+			list = rht_dereference_bucket(list->next, tbl, hash);
+			RCU_INIT_POINTER(*lpprev, list);
+			err = 0;
+			break;
 		}
 
-		rcu_assign_pointer(*pprev, obj->next);
-		err = 0;
+		obj = rht_dereference_bucket(obj->next, tbl, hash);
+
+		if (rhlist) {
+			list = rht_dereference_bucket(list->next, tbl, hash);
+			if (list) {
+				RCU_INIT_POINTER(list->rhead.next, obj);
+				obj = &list->rhead;
+			}
+		}
+
+		rcu_assign_pointer(*pprev, obj);
+		err = 1;
 		break;
 	}
 
 	spin_unlock_bh(lock);
 
+	if (err > 0) {
+		atomic_dec(&ht->nelems);
+		if (unlikely(ht->p.automatic_shrinking &&
+			     rht_shrink_below_30(ht, tbl)))
+			schedule_work(&ht->run_work);
+		err = 0;
+	}
+
 	return err;
 }
 
-/**
- * rhashtable_remove_fast - remove object from hash table
- * @ht:		hash table
- * @obj:	pointer to hash head inside object
- * @params:	hash table parameters
- *
- * Since the hash chain is single linked, the removal operation needs to
- * walk the bucket chain upon removal. The removal operation is thus
- * considerable slow if the hash table is not correctly sized.
- *
- * Will automatically shrink the table via rhashtable_expand() if the
- * shrink_decision function specified at rhashtable_init() returns true.
- *
- * Returns zero on success, -ENOENT if the entry could not be found.
- */
-static inline int rhashtable_remove_fast(
+/* Internal function, please use rhashtable_remove_fast() instead */
+static inline int __rhashtable_remove_fast(
 	struct rhashtable *ht, struct rhash_head *obj,
-	const struct rhashtable_params params)
+	const struct rhashtable_params params, bool rhlist)
 {
 	struct bucket_table *tbl;
 	int err;
@@ -850,24 +1029,60 @@ static inline int rhashtable_remove_fast(
 	 * visible then that guarantees the entry to still be in
 	 * the old tbl if it exists.
 	 */
-	while ((err = __rhashtable_remove_fast(ht, tbl, obj, params)) &&
+	while ((err = __rhashtable_remove_fast_one(ht, tbl, obj, params,
+						   rhlist)) &&
 	       (tbl = rht_dereference_rcu(tbl->future_tbl, ht)))
 		;
 
-	if (err)
-		goto out;
-
-	atomic_dec(&ht->nelems);
-	if (unlikely(ht->p.automatic_shrinking &&
-		     rht_shrink_below_30(ht, tbl)))
-		schedule_work(&ht->run_work);
-
-out:
 	rcu_read_unlock();
 
 	return err;
 }
 
+/**
+ * rhashtable_remove_fast - remove object from hash table
+ * @ht:		hash table
+ * @obj:	pointer to hash head inside object
+ * @params:	hash table parameters
+ *
+ * Since the hash chain is single linked, the removal operation needs to
+ * walk the bucket chain upon removal. The removal operation is thus
+ * considerable slow if the hash table is not correctly sized.
+ *
+ * Will automatically shrink the table via rhashtable_expand() if the
+ * shrink_decision function specified at rhashtable_init() returns true.
+ *
+ * Returns zero on success, -ENOENT if the entry could not be found.
+ */
+static inline int rhashtable_remove_fast(
+	struct rhashtable *ht, struct rhash_head *obj,
+	const struct rhashtable_params params)
+{
+	return __rhashtable_remove_fast(ht, obj, params, false);
+}
+
+/**
+ * rhltable_remove - remove object from hash list table
+ * @hlt:	hash list table
+ * @list:	pointer to hash list head inside object
+ * @params:	hash table parameters
+ *
+ * Since the hash chain is single linked, the removal operation needs to
+ * walk the bucket chain upon removal. The removal operation is thus
+ * considerable slow if the hash table is not correctly sized.
+ *
+ * Will automatically shrink the table via rhashtable_expand() if the
+ * shrink_decision function specified at rhashtable_init() returns true.
+ *
+ * Returns zero on success, -ENOENT if the entry could not be found.
+ */
+static inline int rhltable_remove(
+	struct rhltable *hlt, struct rhlist_head *list,
+	const struct rhashtable_params params)
+{
+	return __rhashtable_remove_fast(&hlt->ht, &list->rhead, params, true);
+}
+
 /* Internal function, please use rhashtable_replace_fast() instead */
 static inline int __rhashtable_replace_fast(
 	struct rhashtable *ht, struct bucket_table *tbl,
@@ -958,4 +1173,51 @@ static inline int rhashtable_walk_init(struct rhashtable *ht,
 	return 0;
 }
 
+/**
+ * rhltable_walk_enter - Initialise an iterator
+ * @hlt:	Table to walk over
+ * @iter:	Hash table Iterator
+ *
+ * This function prepares a hash table walk.
+ *
+ * Note that if you restart a walk after rhashtable_walk_stop you
+ * may see the same object twice.  Also, you may miss objects if
+ * there are removals in between rhashtable_walk_stop and the next
+ * call to rhashtable_walk_start.
+ *
+ * For a completely stable walk you should construct your own data
+ * structure outside the hash table.
+ *
+ * This function may sleep so you must not call it from interrupt
+ * context or with spin locks held.
+ *
+ * You must call rhashtable_walk_exit after this function returns.
+ */
+static inline void rhltable_walk_enter(struct rhltable *hlt,
+				       struct rhashtable_iter *iter)
+{
+	return rhashtable_walk_enter(&hlt->ht, iter);
+}
+
+/**
+ * rhltable_free_and_destroy - free elements and destroy hash list table
+ * @hlt:	the hash list table to destroy
+ * @free_fn:	callback to release resources of element
+ * @arg:	pointer passed to free_fn
+ *
+ * See documentation for rhashtable_free_and_destroy.
+ */
+static inline void rhltable_free_and_destroy(struct rhltable *hlt,
+					     void (*free_fn)(void *ptr,
+							     void *arg),
+					     void *arg)
+{
+	return rhashtable_free_and_destroy(&hlt->ht, free_fn, arg);
+}
+
+static inline void rhltable_destroy(struct rhltable *hlt)
+{
+	return rhltable_free_and_destroy(hlt, NULL, NULL);
+}
+
 #endif /* _LINUX_RHASHTABLE_H */
diff --git a/lib/rhashtable.c b/lib/rhashtable.c
index 06c2872..32d0ad0 100644
--- a/lib/rhashtable.c
+++ b/lib/rhashtable.c
@@ -378,22 +378,8 @@ static void rht_deferred_worker(struct work_struct *work)
 		schedule_work(&ht->run_work);
 }
 
-static bool rhashtable_check_elasticity(struct rhashtable *ht,
-					struct bucket_table *tbl,
-					unsigned int hash)
-{
-	unsigned int elasticity = ht->elasticity;
-	struct rhash_head *head;
-
-	rht_for_each(head, tbl, hash)
-		if (!--elasticity)
-			return true;
-
-	return false;
-}
-
-int rhashtable_insert_rehash(struct rhashtable *ht,
-			     struct bucket_table *tbl)
+static int rhashtable_insert_rehash(struct rhashtable *ht,
+				    struct bucket_table *tbl)
 {
 	struct bucket_table *old_tbl;
 	struct bucket_table *new_tbl;
@@ -439,57 +425,165 @@ fail:
 
 	return err;
 }
-EXPORT_SYMBOL_GPL(rhashtable_insert_rehash);
 
-struct bucket_table *rhashtable_insert_slow(struct rhashtable *ht,
-					    const void *key,
-					    struct rhash_head *obj,
-					    struct bucket_table *tbl,
-					    void **data)
+static void *rhashtable_lookup_one(struct rhashtable *ht,
+				   struct bucket_table *tbl, unsigned int hash,
+				   const void *key, struct rhash_head *obj)
 {
+	struct rhashtable_compare_arg arg = {
+		.ht = ht,
+		.key = key,
+	};
+	struct rhash_head __rcu **pprev;
 	struct rhash_head *head;
-	unsigned int hash;
-	int err;
+	int elasticity;
 
-	tbl = rhashtable_last_table(ht, tbl);
-	hash = head_hashfn(ht, tbl, obj);
-	spin_lock_nested(rht_bucket_lock(tbl, hash), SINGLE_DEPTH_NESTING);
-
-	err = -EEXIST;
-	if (key) {
-		*data = rhashtable_lookup_fast(ht, key, ht->p);
-		if (*data)
-			goto exit;
+	elasticity = ht->elasticity;
+	pprev = &tbl->buckets[hash];
+	rht_for_each(head, tbl, hash) {
+		struct rhlist_head *list;
+		struct rhlist_head *plist;
+
+		elasticity--;
+		if (!key ||
+		    (ht->p.obj_cmpfn ?
+		     ht->p.obj_cmpfn(&arg, rht_obj(ht, head)) :
+		     rhashtable_compare(&arg, rht_obj(ht, head))))
+			continue;
+
+		if (!ht->rhlist)
+			return rht_obj(ht, head);
+
+		list = container_of(obj, struct rhlist_head, rhead);
+		plist = container_of(head, struct rhlist_head, rhead);
+
+		RCU_INIT_POINTER(list->next, plist);
+		head = rht_dereference_bucket(head->next, tbl, hash);
+		RCU_INIT_POINTER(list->rhead.next, head);
+		rcu_assign_pointer(*pprev, obj);
+
+		return NULL;
 	}
 
-	err = -E2BIG;
-	if (unlikely(rht_grow_above_max(ht, tbl)))
-		goto exit;
+	if (elasticity <= 0)
+		return ERR_PTR(-EAGAIN);
+
+	return ERR_PTR(-ENOENT);
+}
+
+static struct bucket_table *rhashtable_insert_one(struct rhashtable *ht,
+						  struct bucket_table *tbl,
+						  unsigned int hash,
+						  struct rhash_head *obj,
+						  void *data)
+{
+	struct bucket_table *new_tbl;
+	struct rhash_head *head;
+
+	if (!IS_ERR_OR_NULL(data))
+		return ERR_PTR(-EEXIST);
 
-	err = -EAGAIN;
-	if (rhashtable_check_elasticity(ht, tbl, hash) ||
-	    rht_grow_above_100(ht, tbl))
-		goto exit;
+	if (PTR_ERR(data) != -EAGAIN && PTR_ERR(data) != -ENOENT)
+		return ERR_CAST(data);
 
-	err = 0;
+	new_tbl = rcu_dereference(tbl->future_tbl);
+	if (new_tbl)
+		return new_tbl;
+
+	if (PTR_ERR(data) != -ENOENT)
+		return ERR_CAST(data);
+
+	if (unlikely(rht_grow_above_max(ht, tbl)))
+		return ERR_PTR(-E2BIG);
+
+	if (unlikely(rht_grow_above_100(ht, tbl)))
+		return ERR_PTR(-EAGAIN);
 
 	head = rht_dereference_bucket(tbl->buckets[hash], tbl, hash);
 
 	RCU_INIT_POINTER(obj->next, head);
+	if (ht->rhlist) {
+		struct rhlist_head *list;
+
+		list = container_of(obj, struct rhlist_head, rhead);
+		RCU_INIT_POINTER(list->next, NULL);
+	}
 
 	rcu_assign_pointer(tbl->buckets[hash], obj);
 
 	atomic_inc(&ht->nelems);
+	if (rht_grow_above_75(ht, tbl))
+		schedule_work(&ht->run_work);
 
-exit:
-	spin_unlock(rht_bucket_lock(tbl, hash));
+	return NULL;
+}
 
-	if (err == 0)
-		return NULL;
-	else if (err == -EAGAIN)
-		return tbl;
-	else
-		return ERR_PTR(err);
+static void *rhashtable_try_insert(struct rhashtable *ht, const void *key,
+				   struct rhash_head *obj)
+{
+	struct bucket_table *new_tbl;
+	struct bucket_table *tbl;
+	unsigned int hash;
+	spinlock_t *lock;
+	void *data;
+
+	tbl = rcu_dereference(ht->tbl);
+
+	/* All insertions must grab the oldest table containing
+	 * the hashed bucket that is yet to be rehashed.
+	 */
+	for (;;) {
+		hash = rht_head_hashfn(ht, tbl, obj, ht->p);
+		lock = rht_bucket_lock(tbl, hash);
+		spin_lock_bh(lock);
+
+		if (tbl->rehash <= hash)
+			break;
+
+		spin_unlock_bh(lock);
+		tbl = rcu_dereference(tbl->future_tbl);
+	}
+
+	data = rhashtable_lookup_one(ht, tbl, hash, key, obj);
+	new_tbl = rhashtable_insert_one(ht, tbl, hash, obj, data);
+	if (PTR_ERR(new_tbl) != -EEXIST)
+		data = ERR_CAST(new_tbl);
+
+	while (!IS_ERR_OR_NULL(new_tbl)) {
+		tbl = new_tbl;
+		hash = rht_head_hashfn(ht, tbl, obj, ht->p);
+		spin_lock_nested(rht_bucket_lock(tbl, hash),
+				 SINGLE_DEPTH_NESTING);
+
+		data = rhashtable_lookup_one(ht, tbl, hash, key, obj);
+		new_tbl = rhashtable_insert_one(ht, tbl, hash, obj, data);
+		if (PTR_ERR(new_tbl) != -EEXIST)
+			data = ERR_CAST(new_tbl);
+
+		spin_unlock(rht_bucket_lock(tbl, hash));
+	}
+
+	spin_unlock_bh(lock);
+
+	if (PTR_ERR(data) == -EAGAIN)
+		data = ERR_PTR(rhashtable_insert_rehash(ht, tbl) ?:
+			       -EAGAIN);
+
+	return data;
+}
+
+void *rhashtable_insert_slow(struct rhashtable *ht, const void *key,
+			     struct rhash_head *obj)
+{
+	void *data;
+
+	do {
+		rcu_read_lock();
+		data = rhashtable_try_insert(ht, key, obj);
+		rcu_read_unlock();
+	} while (PTR_ERR(data) == -EAGAIN);
+
+	return data;
 }
 EXPORT_SYMBOL_GPL(rhashtable_insert_slow);
 
@@ -593,11 +687,16 @@ EXPORT_SYMBOL_GPL(rhashtable_walk_start);
 void *rhashtable_walk_next(struct rhashtable_iter *iter)
 {
 	struct bucket_table *tbl = iter->walker.tbl;
+	struct rhlist_head *list = iter->list;
 	struct rhashtable *ht = iter->ht;
 	struct rhash_head *p = iter->p;
+	bool rhlist = ht->rhlist;
 
 	if (p) {
-		p = rht_dereference_bucket_rcu(p->next, tbl, iter->slot);
+		if (!rhlist || !(list = rcu_dereference(list->next))) {
+			p = rcu_dereference(p->next);
+			list = container_of(p, struct rhlist_head, rhead);
+		}
 		goto next;
 	}
 
@@ -605,6 +704,18 @@ void *rhashtable_walk_next(struct rhashtable_iter *iter)
 		int skip = iter->skip;
 
 		rht_for_each_rcu(p, tbl, iter->slot) {
+			if (rhlist) {
+				list = container_of(p, struct rhlist_head,
+						    rhead);
+				do {
+					if (!skip)
+						goto next;
+					skip--;
+					list = rcu_dereference(list->next);
+				} while (list);
+
+				continue;
+			}
 			if (!skip)
 				break;
 			skip--;
@@ -614,7 +725,8 @@ next:
 		if (!rht_is_a_nulls(p)) {
 			iter->skip++;
 			iter->p = p;
-			return rht_obj(ht, p);
+			iter->list = list;
+			return rht_obj(ht, rhlist ? &list->rhead : p);
 		}
 
 		iter->skip = 0;
@@ -803,6 +915,48 @@ int rhashtable_init(struct rhashtable *ht,
 EXPORT_SYMBOL_GPL(rhashtable_init);
 
 /**
+ * rhltable_init - initialize a new hash list table
+ * @hlt:	hash list table to be initialized
+ * @params:	configuration parameters
+ *
+ * Initializes a new hash list table.
+ *
+ * See documentation for rhashtable_init.
+ */
+int rhltable_init(struct rhltable *hlt, const struct rhashtable_params *params)
+{
+	int err;
+
+	/* No rhlist NULLs marking for now. */
+	if (params->nulls_base)
+		return -EINVAL;
+
+	err = rhashtable_init(&hlt->ht, params);
+	hlt->ht.rhlist = true;
+	return err;
+}
+EXPORT_SYMBOL_GPL(rhltable_init);
+
+static void rhashtable_free_one(struct rhashtable *ht, struct rhash_head *obj,
+				void (*free_fn)(void *ptr, void *arg),
+				void *arg)
+{
+	struct rhlist_head *list;
+
+	if (!ht->rhlist) {
+		free_fn(rht_obj(ht, obj), arg);
+		return;
+	}
+
+	list = container_of(obj, struct rhlist_head, rhead);
+	do {
+		obj = &list->rhead;
+		list = rht_dereference(list->next, ht);
+		free_fn(rht_obj(ht, obj), arg);
+	} while (list);
+}
+
+/**
  * rhashtable_free_and_destroy - free elements and destroy hash table
  * @ht:		the hash table to destroy
  * @free_fn:	callback to release resources of element
@@ -839,7 +993,7 @@ void rhashtable_free_and_destroy(struct rhashtable *ht,
 			     pos = next,
 			     next = !rht_is_a_nulls(pos) ?
 					rht_dereference(pos->next, ht) : NULL)
-				free_fn(rht_obj(ht, pos), arg);
+				rhashtable_free_one(ht, pos, free_fn, arg);
 		}
 	}
 

[v2 PATCH 2/2] mac80211: Use rhltable instead of rhashtable

mac80211 currently uses rhashtable with insecure_elasticity set
to true.  The latter is because of duplicate objects.  What's
more, mac80211 walks the rhashtable chains by hand which is broken
as rhashtable may contain multiple tables due to resizing or
rehashing.

This patch fixes it by converting it to the newly added rhltable
interface which is designed for use with duplicate objects.

With rhltable a lookup returns a list of objects instead of a
single one.  This is then fed into the existing for_each_sta_info
macro.

This patch also deletes the sta_addr_hash function since rhashtable
defaults to jhash.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
---

 net/mac80211/ieee80211_i.h |    2 -
 net/mac80211/rx.c          |    7 +-----
 net/mac80211/sta_info.c    |   52 ++++++++++++++++++---------------------------
 net/mac80211/sta_info.h    |   19 ++++++----------
 net/mac80211/status.c      |    7 +-----
 5 files changed, 33 insertions(+), 54 deletions(-)

diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index f56d342..1a52cd4 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -1208,7 +1208,7 @@ struct ieee80211_local {
 	spinlock_t tim_lock;
 	unsigned long num_sta;
 	struct list_head sta_list;
-	struct rhashtable sta_hash;
+	struct rhltable sta_hash;
 	struct timer_list sta_cleanup;
 	int sta_generation;
 
diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index 9dce3b1..5e26dc6 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -3940,7 +3940,7 @@ static void __ieee80211_rx_handle_packet(struct ieee80211_hw *hw,
 	__le16 fc;
 	struct ieee80211_rx_data rx;
 	struct ieee80211_sub_if_data *prev;
-	struct rhash_head *tmp;
+	struct rhlist_head *tmp;
 	int err = 0;
 
 	fc = ((struct ieee80211_hdr *)skb->data)->frame_control;
@@ -3983,13 +3983,10 @@ static void __ieee80211_rx_handle_packet(struct ieee80211_hw *hw,
 		goto out;
 	} else if (ieee80211_is_data(fc)) {
 		struct sta_info *sta, *prev_sta;
-		const struct bucket_table *tbl;
 
 		prev_sta = NULL;
 
-		tbl = rht_dereference_rcu(local->sta_hash.tbl, &local->sta_hash);
-
-		for_each_sta_info(local, tbl, hdr->addr2, sta, tmp) {
+		for_each_sta_info(local, hdr->addr2, sta, tmp) {
 			if (!prev_sta) {
 				prev_sta = sta;
 				continue;
diff --git a/net/mac80211/sta_info.c b/net/mac80211/sta_info.c
index 19f14c9..198d0bd 100644
--- a/net/mac80211/sta_info.c
+++ b/net/mac80211/sta_info.c
@@ -67,12 +67,10 @@
 
 static const struct rhashtable_params sta_rht_params = {
 	.nelem_hint = 3, /* start small */
-	.insecure_elasticity = true, /* Disable chain-length checks. */
 	.automatic_shrinking = true,
 	.head_offset = offsetof(struct sta_info, hash_node),
 	.key_offset = offsetof(struct sta_info, addr),
 	.key_len = ETH_ALEN,
-	.hashfn = sta_addr_hash,
 	.max_size = CONFIG_MAC80211_STA_HASH_MAX_SIZE,
 };
 
@@ -80,8 +78,8 @@ static const struct rhashtable_params sta_rht_params = {
 static int sta_info_hash_del(struct ieee80211_local *local,
 			     struct sta_info *sta)
 {
-	return rhashtable_remove_fast(&local->sta_hash, &sta->hash_node,
-				      sta_rht_params);
+	return rhltable_remove(&local->sta_hash, &sta->hash_node,
+			       sta_rht_params);
 }
 
 static void __cleanup_single_sta(struct sta_info *sta)
@@ -157,19 +155,22 @@ static void cleanup_single_sta(struct sta_info *sta)
 	sta_info_free(local, sta);
 }
 
+struct rhlist_head *sta_info_hash_lookup(struct ieee80211_local *local,
+					 const u8 *addr)
+{
+	return rhltable_lookup(&local->sta_hash, addr, sta_rht_params);
+}
+
 /* protected by RCU */
 struct sta_info *sta_info_get(struct ieee80211_sub_if_data *sdata,
 			      const u8 *addr)
 {
 	struct ieee80211_local *local = sdata->local;
+	struct rhlist_head *tmp;
 	struct sta_info *sta;
-	struct rhash_head *tmp;
-	const struct bucket_table *tbl;
 
 	rcu_read_lock();
-	tbl = rht_dereference_rcu(local->sta_hash.tbl, &local->sta_hash);
-
-	for_each_sta_info(local, tbl, addr, sta, tmp) {
+	for_each_sta_info(local, addr, sta, tmp) {
 		if (sta->sdata == sdata) {
 			rcu_read_unlock();
 			/* this is safe as the caller must already hold
@@ -190,14 +191,11 @@ struct sta_info *sta_info_get_bss(struct ieee80211_sub_if_data *sdata,
 				  const u8 *addr)
 {
 	struct ieee80211_local *local = sdata->local;
+	struct rhlist_head *tmp;
 	struct sta_info *sta;
-	struct rhash_head *tmp;
-	const struct bucket_table *tbl;
 
 	rcu_read_lock();
-	tbl = rht_dereference_rcu(local->sta_hash.tbl, &local->sta_hash);
-
-	for_each_sta_info(local, tbl, addr, sta, tmp) {
+	for_each_sta_info(local, addr, sta, tmp) {
 		if (sta->sdata == sdata ||
 		    (sta->sdata->bss && sta->sdata->bss == sdata->bss)) {
 			rcu_read_unlock();
@@ -263,8 +261,8 @@ void sta_info_free(struct ieee80211_local *local, struct sta_info *sta)
 static int sta_info_hash_add(struct ieee80211_local *local,
 			     struct sta_info *sta)
 {
-	return rhashtable_insert_fast(&local->sta_hash, &sta->hash_node,
-				      sta_rht_params);
+	return rhltable_insert(&local->sta_hash, &sta->hash_node,
+			       sta_rht_params);
 }
 
 static void sta_deliver_ps_frames(struct work_struct *wk)
@@ -450,9 +448,9 @@ static int sta_info_insert_check(struct sta_info *sta)
 		    is_multicast_ether_addr(sta->sta.addr)))
 		return -EINVAL;
 
-	/* Strictly speaking this isn't necessary as we hold the mutex, but
-	 * the rhashtable code can't really deal with that distinction. We
-	 * do require the mutex for correctness though.
+	/* The RCU read lock is required by rhashtable due to
+	 * asynchronous resize/rehash.  We also require the mutex
+	 * for correctness.
 	 */
 	rcu_read_lock();
 	lockdep_assert_held(&sdata->local->sta_mtx);
@@ -1040,16 +1038,11 @@ static void sta_info_cleanup(unsigned long data)
 		  round_jiffies(jiffies + STA_INFO_CLEANUP_INTERVAL));
 }
 
-u32 sta_addr_hash(const void *key, u32 length, u32 seed)
-{
-	return jhash(key, ETH_ALEN, seed);
-}
-
 int sta_info_init(struct ieee80211_local *local)
 {
 	int err;
 
-	err = rhashtable_init(&local->sta_hash, &sta_rht_params);
+	err = rhltable_init(&local->sta_hash, &sta_rht_params);
 	if (err)
 		return err;
 
@@ -1065,7 +1058,7 @@ int sta_info_init(struct ieee80211_local *local)
 void sta_info_stop(struct ieee80211_local *local)
 {
 	del_timer_sync(&local->sta_cleanup);
-	rhashtable_destroy(&local->sta_hash);
+	rhltable_destroy(&local->sta_hash);
 }
 
 
@@ -1135,17 +1128,14 @@ struct ieee80211_sta *ieee80211_find_sta_by_ifaddr(struct ieee80211_hw *hw,
 						   const u8 *localaddr)
 {
 	struct ieee80211_local *local = hw_to_local(hw);
+	struct rhlist_head *tmp;
 	struct sta_info *sta;
-	struct rhash_head *tmp;
-	const struct bucket_table *tbl;
-
-	tbl = rht_dereference_rcu(local->sta_hash.tbl, &local->sta_hash);
 
 	/*
 	 * Just return a random station if localaddr is NULL
 	 * ... first in list.
 	 */
-	for_each_sta_info(local, tbl, addr, sta, tmp) {
+	for_each_sta_info(local, addr, sta, tmp) {
 		if (localaddr &&
 		    !ether_addr_equal(sta->sdata->vif.addr, localaddr))
 			continue;
diff --git a/net/mac80211/sta_info.h b/net/mac80211/sta_info.h
index 0556be3..d347ab5 100644
--- a/net/mac80211/sta_info.h
+++ b/net/mac80211/sta_info.h
@@ -452,7 +452,7 @@ struct sta_info {
 	/* General information, mostly static */
 	struct list_head list, free_list;
 	struct rcu_head rcu_head;
-	struct rhash_head hash_node;
+	struct rhlist_head hash_node;
 	u8 addr[ETH_ALEN];
 	struct ieee80211_local *local;
 	struct ieee80211_sub_if_data *sdata;
@@ -635,6 +635,9 @@ rcu_dereference_protected_tid_tx(struct sta_info *sta, int tid)
  */
 #define STA_INFO_CLEANUP_INTERVAL (10 * HZ)
 
+struct rhlist_head *sta_info_hash_lookup(struct ieee80211_local *local,
+					 const u8 *addr);
+
 /*
  * Get a STA info, must be under RCU read lock.
  */
@@ -644,17 +647,9 @@ struct sta_info *sta_info_get(struct ieee80211_sub_if_data *sdata,
 struct sta_info *sta_info_get_bss(struct ieee80211_sub_if_data *sdata,
 				  const u8 *addr);
 
-u32 sta_addr_hash(const void *key, u32 length, u32 seed);
-
-#define _sta_bucket_idx(_tbl, _a)					\
-	rht_bucket_index(_tbl, sta_addr_hash(_a, ETH_ALEN, (_tbl)->hash_rnd))
-
-#define for_each_sta_info(local, tbl, _addr, _sta, _tmp)		\
-	rht_for_each_entry_rcu(_sta, _tmp, tbl, 			\
-			       _sta_bucket_idx(tbl, _addr),		\
-			       hash_node)				\
-	/* compare address and run code only if it matches */		\
-	if (ether_addr_equal(_sta->addr, (_addr)))
+#define for_each_sta_info(local, _addr, _sta, _tmp)			\
+	rhl_for_each_entry_rcu(_sta, _tmp,				\
+			       sta_info_hash_lookup(local, _addr), hash_node)
 
 /*
  * Get STA info by index, BROKEN!
diff --git a/net/mac80211/status.c b/net/mac80211/status.c
index a2a6826..6361709 100644
--- a/net/mac80211/status.c
+++ b/net/mac80211/status.c
@@ -740,8 +740,8 @@ void ieee80211_tx_status(struct ieee80211_hw *hw, struct sk_buff *skb)
 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 	__le16 fc;
 	struct ieee80211_supported_band *sband;
+	struct rhlist_head *tmp;
 	struct sta_info *sta;
-	struct rhash_head *tmp;
 	int retry_count;
 	int rates_idx;
 	bool send_to_cooked;
@@ -749,7 +749,6 @@ void ieee80211_tx_status(struct ieee80211_hw *hw, struct sk_buff *skb)
 	struct ieee80211_bar *bar;
 	int shift = 0;
 	int tid = IEEE80211_NUM_TIDS;
-	const struct bucket_table *tbl;
 
 	rates_idx = ieee80211_tx_get_rates(hw, info, &retry_count);
 
@@ -758,9 +757,7 @@ void ieee80211_tx_status(struct ieee80211_hw *hw, struct sk_buff *skb)
 	sband = local->hw.wiphy->bands[info->band];
 	fc = hdr->frame_control;
 
-	tbl = rht_dereference_rcu(local->sta_hash.tbl, &local->sta_hash);
-
-	for_each_sta_info(local, tbl, hdr->addr1, sta, tmp) {
+	for_each_sta_info(local, hdr->addr1, sta, tmp) {
 		/* skip wrong virtual interface */
 		if (!ether_addr_equal(hdr->addr2, sta->sdata->vif.addr))
 			continue;

[v2 PATCH 2/2] mac80211: Use rhltable instead of rhashtable

[Herbert Xu]

mac80211 currently uses rhashtable with insecure_elasticity set
to true.  The latter is because of duplicate objects.  What's
more, mac80211 walks the rhashtable chains by hand which is broken
as rhashtable may contain multiple tables due to resizing or
rehashing.

This patch fixes it by converting it to the newly added rhltable
interface which is designed for use with duplicate objects.

With rhltable a lookup returns a list of objects instead of a
single one.  This is then fed into the existing for_each_sta_info
macro.

This patch also deletes the sta_addr_hash function since rhashtable
defaults to jhash.

Signed-off-by: Herbert Xu <herbert-lOAM2aK0SrRLBo1qDEOMRrpzq4S04n8Q@public.gmane.org>
---

 net/mac80211/ieee80211_i.h |    2 -
 net/mac80211/rx.c          |    7 +-----
 net/mac80211/sta_info.c    |   52 ++++++++++++++++++---------------------------
 net/mac80211/sta_info.h    |   19 ++++++----------
 net/mac80211/status.c      |    7 +-----
 5 files changed, 33 insertions(+), 54 deletions(-)

diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index f56d342..1a52cd4 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -1208,7 +1208,7 @@ struct ieee80211_local {
 	spinlock_t tim_lock;
 	unsigned long num_sta;
 	struct list_head sta_list;
-	struct rhashtable sta_hash;
+	struct rhltable sta_hash;
 	struct timer_list sta_cleanup;
 	int sta_generation;
 
diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index 9dce3b1..5e26dc6 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -3940,7 +3940,7 @@ static void __ieee80211_rx_handle_packet(struct ieee80211_hw *hw,
 	__le16 fc;
 	struct ieee80211_rx_data rx;
 	struct ieee80211_sub_if_data *prev;
-	struct rhash_head *tmp;
+	struct rhlist_head *tmp;
 	int err = 0;
 
 	fc = ((struct ieee80211_hdr *)skb->data)->frame_control;
@@ -3983,13 +3983,10 @@ static void __ieee80211_rx_handle_packet(struct ieee80211_hw *hw,
 		goto out;
 	} else if (ieee80211_is_data(fc)) {
 		struct sta_info *sta, *prev_sta;
-		const struct bucket_table *tbl;
 
 		prev_sta = NULL;
 
-		tbl = rht_dereference_rcu(local->sta_hash.tbl, &local->sta_hash);
-
-		for_each_sta_info(local, tbl, hdr->addr2, sta, tmp) {
+		for_each_sta_info(local, hdr->addr2, sta, tmp) {
 			if (!prev_sta) {
 				prev_sta = sta;
 				continue;
diff --git a/net/mac80211/sta_info.c b/net/mac80211/sta_info.c
index 19f14c9..198d0bd 100644
--- a/net/mac80211/sta_info.c
+++ b/net/mac80211/sta_info.c
@@ -67,12 +67,10 @@
 
 static const struct rhashtable_params sta_rht_params = {
 	.nelem_hint = 3, /* start small */
-	.insecure_elasticity = true, /* Disable chain-length checks. */
 	.automatic_shrinking = true,
 	.head_offset = offsetof(struct sta_info, hash_node),
 	.key_offset = offsetof(struct sta_info, addr),
 	.key_len = ETH_ALEN,
-	.hashfn = sta_addr_hash,
 	.max_size = CONFIG_MAC80211_STA_HASH_MAX_SIZE,
 };
 
@@ -80,8 +78,8 @@ static const struct rhashtable_params sta_rht_params = {
 static int sta_info_hash_del(struct ieee80211_local *local,
 			     struct sta_info *sta)
 {
-	return rhashtable_remove_fast(&local->sta_hash, &sta->hash_node,
-				      sta_rht_params);
+	return rhltable_remove(&local->sta_hash, &sta->hash_node,
+			       sta_rht_params);
 }
 
 static void __cleanup_single_sta(struct sta_info *sta)
@@ -157,19 +155,22 @@ static void cleanup_single_sta(struct sta_info *sta)
 	sta_info_free(local, sta);
 }
 
+struct rhlist_head *sta_info_hash_lookup(struct ieee80211_local *local,
+					 const u8 *addr)
+{
+	return rhltable_lookup(&local->sta_hash, addr, sta_rht_params);
+}
+
 /* protected by RCU */
 struct sta_info *sta_info_get(struct ieee80211_sub_if_data *sdata,
 			      const u8 *addr)
 {
 	struct ieee80211_local *local = sdata->local;
+	struct rhlist_head *tmp;
 	struct sta_info *sta;
-	struct rhash_head *tmp;
-	const struct bucket_table *tbl;
 
 	rcu_read_lock();
-	tbl = rht_dereference_rcu(local->sta_hash.tbl, &local->sta_hash);
-
-	for_each_sta_info(local, tbl, addr, sta, tmp) {
+	for_each_sta_info(local, addr, sta, tmp) {
 		if (sta->sdata == sdata) {
 			rcu_read_unlock();
 			/* this is safe as the caller must already hold
@@ -190,14 +191,11 @@ struct sta_info *sta_info_get_bss(struct ieee80211_sub_if_data *sdata,
 				  const u8 *addr)
 {
 	struct ieee80211_local *local = sdata->local;
+	struct rhlist_head *tmp;
 	struct sta_info *sta;
-	struct rhash_head *tmp;
-	const struct bucket_table *tbl;
 
 	rcu_read_lock();
-	tbl = rht_dereference_rcu(local->sta_hash.tbl, &local->sta_hash);
-
-	for_each_sta_info(local, tbl, addr, sta, tmp) {
+	for_each_sta_info(local, addr, sta, tmp) {
 		if (sta->sdata == sdata ||
 		    (sta->sdata->bss && sta->sdata->bss == sdata->bss)) {
 			rcu_read_unlock();
@@ -263,8 +261,8 @@ void sta_info_free(struct ieee80211_local *local, struct sta_info *sta)
 static int sta_info_hash_add(struct ieee80211_local *local,
 			     struct sta_info *sta)
 {
-	return rhashtable_insert_fast(&local->sta_hash, &sta->hash_node,
-				      sta_rht_params);
+	return rhltable_insert(&local->sta_hash, &sta->hash_node,
+			       sta_rht_params);
 }
 
 static void sta_deliver_ps_frames(struct work_struct *wk)
@@ -450,9 +448,9 @@ static int sta_info_insert_check(struct sta_info *sta)
 		    is_multicast_ether_addr(sta->sta.addr)))
 		return -EINVAL;
 
-	/* Strictly speaking this isn't necessary as we hold the mutex, but
-	 * the rhashtable code can't really deal with that distinction. We
-	 * do require the mutex for correctness though.
+	/* The RCU read lock is required by rhashtable due to
+	 * asynchronous resize/rehash.  We also require the mutex
+	 * for correctness.
 	 */
 	rcu_read_lock();
 	lockdep_assert_held(&sdata->local->sta_mtx);
@@ -1040,16 +1038,11 @@ static void sta_info_cleanup(unsigned long data)
 		  round_jiffies(jiffies + STA_INFO_CLEANUP_INTERVAL));
 }
 
-u32 sta_addr_hash(const void *key, u32 length, u32 seed)
-{
-	return jhash(key, ETH_ALEN, seed);
-}
-
 int sta_info_init(struct ieee80211_local *local)
 {
 	int err;
 
-	err = rhashtable_init(&local->sta_hash, &sta_rht_params);
+	err = rhltable_init(&local->sta_hash, &sta_rht_params);
 	if (err)
 		return err;
 
@@ -1065,7 +1058,7 @@ int sta_info_init(struct ieee80211_local *local)
 void sta_info_stop(struct ieee80211_local *local)
 {
 	del_timer_sync(&local->sta_cleanup);
-	rhashtable_destroy(&local->sta_hash);
+	rhltable_destroy(&local->sta_hash);
 }
 
 
@@ -1135,17 +1128,14 @@ struct ieee80211_sta *ieee80211_find_sta_by_ifaddr(struct ieee80211_hw *hw,
 						   const u8 *localaddr)
 {
 	struct ieee80211_local *local = hw_to_local(hw);
+	struct rhlist_head *tmp;
 	struct sta_info *sta;
-	struct rhash_head *tmp;
-	const struct bucket_table *tbl;
-
-	tbl = rht_dereference_rcu(local->sta_hash.tbl, &local->sta_hash);
 
 	/*
 	 * Just return a random station if localaddr is NULL
 	 * ... first in list.
 	 */
-	for_each_sta_info(local, tbl, addr, sta, tmp) {
+	for_each_sta_info(local, addr, sta, tmp) {
 		if (localaddr &&
 		    !ether_addr_equal(sta->sdata->vif.addr, localaddr))
 			continue;
diff --git a/net/mac80211/sta_info.h b/net/mac80211/sta_info.h
index 0556be3..d347ab5 100644
--- a/net/mac80211/sta_info.h
+++ b/net/mac80211/sta_info.h
@@ -452,7 +452,7 @@ struct sta_info {
 	/* General information, mostly static */
 	struct list_head list, free_list;
 	struct rcu_head rcu_head;
-	struct rhash_head hash_node;
+	struct rhlist_head hash_node;
 	u8 addr[ETH_ALEN];
 	struct ieee80211_local *local;
 	struct ieee80211_sub_if_data *sdata;
@@ -635,6 +635,9 @@ rcu_dereference_protected_tid_tx(struct sta_info *sta, int tid)
  */
 #define STA_INFO_CLEANUP_INTERVAL (10 * HZ)
 
+struct rhlist_head *sta_info_hash_lookup(struct ieee80211_local *local,
+					 const u8 *addr);
+
 /*
  * Get a STA info, must be under RCU read lock.
  */
@@ -644,17 +647,9 @@ struct sta_info *sta_info_get(struct ieee80211_sub_if_data *sdata,
 struct sta_info *sta_info_get_bss(struct ieee80211_sub_if_data *sdata,
 				  const u8 *addr);
 
-u32 sta_addr_hash(const void *key, u32 length, u32 seed);
-
-#define _sta_bucket_idx(_tbl, _a)					\
-	rht_bucket_index(_tbl, sta_addr_hash(_a, ETH_ALEN, (_tbl)->hash_rnd))
-
-#define for_each_sta_info(local, tbl, _addr, _sta, _tmp)		\
-	rht_for_each_entry_rcu(_sta, _tmp, tbl, 			\
-			       _sta_bucket_idx(tbl, _addr),		\
-			       hash_node)				\
-	/* compare address and run code only if it matches */		\
-	if (ether_addr_equal(_sta->addr, (_addr)))
+#define for_each_sta_info(local, _addr, _sta, _tmp)			\
+	rhl_for_each_entry_rcu(_sta, _tmp,				\
+			       sta_info_hash_lookup(local, _addr), hash_node)
 
 /*
  * Get STA info by index, BROKEN!
diff --git a/net/mac80211/status.c b/net/mac80211/status.c
index a2a6826..6361709 100644
--- a/net/mac80211/status.c
+++ b/net/mac80211/status.c
@@ -740,8 +740,8 @@ void ieee80211_tx_status(struct ieee80211_hw *hw, struct sk_buff *skb)
 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 	__le16 fc;
 	struct ieee80211_supported_band *sband;
+	struct rhlist_head *tmp;
 	struct sta_info *sta;
-	struct rhash_head *tmp;
 	int retry_count;
 	int rates_idx;
 	bool send_to_cooked;
@@ -749,7 +749,6 @@ void ieee80211_tx_status(struct ieee80211_hw *hw, struct sk_buff *skb)
 	struct ieee80211_bar *bar;
 	int shift = 0;
 	int tid = IEEE80211_NUM_TIDS;
-	const struct bucket_table *tbl;
 
 	rates_idx = ieee80211_tx_get_rates(hw, info, &retry_count);
 
@@ -758,9 +757,7 @@ void ieee80211_tx_status(struct ieee80211_hw *hw, struct sk_buff *skb)
 	sband = local->hw.wiphy->bands[info->band];
 	fc = hdr->frame_control;
 
-	tbl = rht_dereference_rcu(local->sta_hash.tbl, &local->sta_hash);

Re: [PATCH 0/2] rhashtable: rhashtable with duplicate objects

[Johannes Berg]

> > I take that back. I think it's leaking memory - my tests never used
> > to run out of memory, but now they eventually do.
> 
> > I'll try to figure out more.
> 
> Interesting.  The kernel test robot found a bug in the insertion
> slowpath where we end up inserting without taking the inner spinlock
> in case of a nested table.  Not sure whether that's the same issue
> as you're seeing but I'll do a v2 posting.

Increasing the memory for the VMs from 384MB to 512MB didn't avoid the
issue, so there's a definite leak somewhere, although this time fewer
VMs crashed :)

Reverting the patches and running with 384MB then works, so it's not
something else added in the meantime (I ran last a few days ago, but
don't think I merged anything interesting in the meantime).

I'll test your new patches in a minute.

johannes

Re: [v2 PATCH 0/2] rhashtable: rhashtable with duplicate objects

[Johannes Berg]

On Mon, 2016-09-19 at 16:40 +0800, Herbert Xu wrote:

> I've tested the rhlist code with test_rhashtable but I haven't
> tested the mac80211 conversion.  So please give it a go and see
> if it still works.

This is still running out of memory on my test suite.

Somehow I don't see kmemleak kicking in, so I'll have to find the bug
manually :)

johannes

Re: [v2 PATCH 0/2] rhashtable: rhashtable with duplicate objects

[Herbert Xu]

On Mon, Sep 19, 2016 at 11:15:30AM +0200, Johannes Berg wrote:
> On Mon, 2016-09-19 at 16:40 +0800, Herbert Xu wrote:
> 
> > I've tested the rhlist code with test_rhashtable but I haven't
> > tested the mac80211 conversion.  So please give it a go and see
> > if it still works.
> 
> This is still running out of memory on my test suite.
> 
> Somehow I don't see kmemleak kicking in, so I'll have to find the bug
> manually :)

What does your test suite actually do? Is it something that I
can run without special hardware?

Thanks,
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

Re: [v2 PATCH 0/2] rhashtable: rhashtable with duplicate objects

[Herbert Xu]

On Mon, Sep 19, 2016 at 11:15:30AM +0200, Johannes Berg wrote:
> On Mon, 2016-09-19 at 16:40 +0800, Herbert Xu wrote:
> 
> > I've tested the rhlist code with test_rhashtable but I haven't
> > tested the mac80211 conversion.  So please give it a go and see
> > if it still works.
> 
> This is still running out of memory on my test suite.
> 
> Somehow I don't see kmemleak kicking in, so I'll have to find the bug
> manually :)

What does your test suite actually do? Is it something that I
can run without special hardware?

Thanks,
-- 
Email: Herbert Xu <herbert-lOAM2aK0SrRLBo1qDEOMRrpzq4S04n8Q@public.gmane.org>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

Re: [v2 PATCH 0/2] rhashtable: rhashtable with duplicate objects

[Johannes Berg]

[-- Attachment #1: Type: text/plain, Size: 571 bytes --]


> What does your test suite actually do? Is it something that I
> can run without special hardware?

Yes, it's pretty simple - it spins up a number of VMs with hwsim and
just runs a lot of tests:

https://w1.fi/cgit/hostap/tree/tests/hwsim

I've attached a kernel .config you can use for it.

I'm running 7 VMs (vm/parallel-vm.py 7), which makes it faster, but you
can probably reproduce the bug better with a single VM.

I have a feeling there's a bug with ht->nelems, since the crash is
always in the grow worker, but I haven't quite put my finger on it yet.

johannes

[-- Attachment #2: .config --]
[-- Type: text/x-mpsub, Size: 61119 bytes --]

#
# Automatically generated file; DO NOT EDIT.
# Linux/x86 4.8.0-rc4 Kernel Configuration
#
CONFIG_64BIT=y
CONFIG_X86_64=y
CONFIG_X86=y
CONFIG_INSTRUCTION_DECODER=y
CONFIG_OUTPUT_FORMAT="elf64-x86-64"
CONFIG_ARCH_DEFCONFIG="arch/x86/configs/x86_64_defconfig"
CONFIG_LOCKDEP_SUPPORT=y
CONFIG_STACKTRACE_SUPPORT=y
CONFIG_MMU=y
CONFIG_ARCH_MMAP_RND_BITS_MIN=28
CONFIG_ARCH_MMAP_RND_BITS_MAX=32
CONFIG_ARCH_MMAP_RND_COMPAT_BITS_MIN=8
CONFIG_ARCH_MMAP_RND_COMPAT_BITS_MAX=16
CONFIG_NEED_DMA_MAP_STATE=y
CONFIG_NEED_SG_DMA_LENGTH=y
CONFIG_GENERIC_BUG=y
CONFIG_GENERIC_BUG_RELATIVE_POINTERS=y
CONFIG_GENERIC_HWEIGHT=y
CONFIG_RWSEM_XCHGADD_ALGORITHM=y
CONFIG_GENERIC_CALIBRATE_DELAY=y
CONFIG_ARCH_HAS_CPU_RELAX=y
CONFIG_ARCH_HAS_CACHE_LINE_SIZE=y
CONFIG_HAVE_SETUP_PER_CPU_AREA=y
CONFIG_NEED_PER_CPU_EMBED_FIRST_CHUNK=y
CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK=y
CONFIG_ARCH_HIBERNATION_POSSIBLE=y
CONFIG_ARCH_SUSPEND_POSSIBLE=y
CONFIG_ARCH_WANT_HUGE_PMD_SHARE=y
CONFIG_ARCH_WANT_GENERAL_HUGETLB=y
CONFIG_ZONE_DMA32=y
CONFIG_AUDIT_ARCH=y
CONFIG_ARCH_SUPPORTS_OPTIMIZED_INLINING=y
CONFIG_ARCH_SUPPORTS_DEBUG_PAGEALLOC=y
CONFIG_X86_64_SMP=y
CONFIG_ARCH_SUPPORTS_UPROBES=y
CONFIG_FIX_EARLYCON_MEM=y
CONFIG_DEBUG_RODATA=y
CONFIG_PGTABLE_LEVELS=4
CONFIG_DEFCONFIG_LIST="/lib/modules/$UNAME_RELEASE/.config"
CONFIG_CONSTRUCTORS=y
CONFIG_IRQ_WORK=y
CONFIG_BUILDTIME_EXTABLE_SORT=y

#
# General setup
#
CONFIG_INIT_ENV_ARG_LIMIT=32
CONFIG_CROSS_COMPILE=""
# CONFIG_COMPILE_TEST is not set
CONFIG_LOCALVERSION=""
# CONFIG_LOCALVERSION_AUTO is not set
CONFIG_HAVE_KERNEL_GZIP=y
CONFIG_HAVE_KERNEL_BZIP2=y
CONFIG_HAVE_KERNEL_LZMA=y
CONFIG_HAVE_KERNEL_XZ=y
CONFIG_HAVE_KERNEL_LZO=y
CONFIG_HAVE_KERNEL_LZ4=y
# CONFIG_KERNEL_GZIP is not set
CONFIG_KERNEL_BZIP2=y
# CONFIG_KERNEL_LZMA is not set
# CONFIG_KERNEL_XZ is not set
# CONFIG_KERNEL_LZO is not set
# CONFIG_KERNEL_LZ4 is not set
CONFIG_DEFAULT_HOSTNAME="(none)"
# CONFIG_SWAP is not set
CONFIG_SYSVIPC=y
CONFIG_SYSVIPC_SYSCTL=y
# CONFIG_POSIX_MQUEUE is not set
# CONFIG_CROSS_MEMORY_ATTACH is not set
# CONFIG_FHANDLE is not set
CONFIG_USELIB=y
# CONFIG_AUDIT is not set
CONFIG_HAVE_ARCH_AUDITSYSCALL=y

#
# IRQ subsystem
#
CONFIG_GENERIC_IRQ_PROBE=y
CONFIG_GENERIC_IRQ_SHOW=y
CONFIG_GENERIC_PENDING_IRQ=y
CONFIG_IRQ_DOMAIN=y
CONFIG_IRQ_DOMAIN_HIERARCHY=y
# CONFIG_IRQ_DOMAIN_DEBUG is not set
CONFIG_IRQ_FORCED_THREADING=y
CONFIG_SPARSE_IRQ=y
CONFIG_CLOCKSOURCE_WATCHDOG=y
CONFIG_ARCH_CLOCKSOURCE_DATA=y
CONFIG_CLOCKSOURCE_VALIDATE_LAST_CYCLE=y
CONFIG_GENERIC_TIME_VSYSCALL=y
CONFIG_GENERIC_CLOCKEVENTS=y
CONFIG_GENERIC_CLOCKEVENTS_BROADCAST=y
CONFIG_GENERIC_CLOCKEVENTS_MIN_ADJUST=y
CONFIG_GENERIC_CMOS_UPDATE=y

#
# Timers subsystem
#
CONFIG_TICK_ONESHOT=y
CONFIG_NO_HZ_COMMON=y
# CONFIG_HZ_PERIODIC is not set
CONFIG_NO_HZ_IDLE=y
# CONFIG_NO_HZ_FULL is not set
CONFIG_NO_HZ=y
CONFIG_HIGH_RES_TIMERS=y

#
# CPU/Task time and stats accounting
#
CONFIG_TICK_CPU_ACCOUNTING=y
# CONFIG_VIRT_CPU_ACCOUNTING_GEN is not set
# CONFIG_IRQ_TIME_ACCOUNTING is not set
CONFIG_BSD_PROCESS_ACCT=y
# CONFIG_BSD_PROCESS_ACCT_V3 is not set
CONFIG_TASKSTATS=y
CONFIG_TASK_DELAY_ACCT=y
CONFIG_TASK_XACCT=y
CONFIG_TASK_IO_ACCOUNTING=y

#
# RCU Subsystem
#
CONFIG_PREEMPT_RCU=y
# CONFIG_RCU_EXPERT is not set
CONFIG_SRCU=y
# CONFIG_TASKS_RCU is not set
CONFIG_RCU_STALL_COMMON=y
# CONFIG_TREE_RCU_TRACE is not set
# CONFIG_RCU_EXPEDITE_BOOT is not set
# CONFIG_BUILD_BIN2C is not set
# CONFIG_IKCONFIG is not set
CONFIG_LOG_BUF_SHIFT=21
CONFIG_LOG_CPU_MAX_BUF_SHIFT=17
CONFIG_NMI_LOG_BUF_SHIFT=13
CONFIG_HAVE_UNSTABLE_SCHED_CLOCK=y
CONFIG_ARCH_SUPPORTS_NUMA_BALANCING=y
CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH=y
CONFIG_ARCH_SUPPORTS_INT128=y
# CONFIG_CGROUPS is not set
# CONFIG_CHECKPOINT_RESTORE is not set
# CONFIG_NAMESPACES is not set
# CONFIG_SCHED_AUTOGROUP is not set
# CONFIG_SYSFS_DEPRECATED is not set
# CONFIG_RELAY is not set
# CONFIG_BLK_DEV_INITRD is not set
CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE=y
# CONFIG_CC_OPTIMIZE_FOR_SIZE is not set
CONFIG_SYSCTL=y
CONFIG_ANON_INODES=y
CONFIG_SYSCTL_EXCEPTION_TRACE=y
CONFIG_HAVE_PCSPKR_PLATFORM=y
CONFIG_BPF=y
CONFIG_EXPERT=y
CONFIG_MULTIUSER=y
CONFIG_SGETMASK_SYSCALL=y
CONFIG_SYSFS_SYSCALL=y
CONFIG_SYSCTL_SYSCALL=y
CONFIG_KALLSYMS=y
CONFIG_KALLSYMS_ALL=y
CONFIG_KALLSYMS_ABSOLUTE_PERCPU=y
CONFIG_KALLSYMS_BASE_RELATIVE=y
CONFIG_PRINTK=y
CONFIG_PRINTK_NMI=y
CONFIG_BUG=y
CONFIG_ELF_CORE=y
CONFIG_PCSPKR_PLATFORM=y
CONFIG_BASE_FULL=y
CONFIG_FUTEX=y
CONFIG_EPOLL=y
CONFIG_SIGNALFD=y
CONFIG_TIMERFD=y
CONFIG_EVENTFD=y
# CONFIG_BPF_SYSCALL is not set
CONFIG_SHMEM=y
CONFIG_AIO=y
CONFIG_ADVISE_SYSCALLS=y
# CONFIG_USERFAULTFD is not set
CONFIG_PCI_QUIRKS=y
CONFIG_MEMBARRIER=y
CONFIG_EMBEDDED=y
CONFIG_HAVE_PERF_EVENTS=y

#
# Kernel Performance Events And Counters
#
CONFIG_PERF_EVENTS=y
# CONFIG_DEBUG_PERF_USE_VMALLOC is not set
CONFIG_VM_EVENT_COUNTERS=y
CONFIG_SLUB_DEBUG=y
# CONFIG_COMPAT_BRK is not set
# CONFIG_SLAB is not set
CONFIG_SLUB=y
# CONFIG_SLOB is not set
# CONFIG_SLAB_FREELIST_RANDOM is not set
CONFIG_SLUB_CPU_PARTIAL=y
# CONFIG_SYSTEM_DATA_VERIFICATION is not set
# CONFIG_PROFILING is not set
CONFIG_TRACEPOINTS=y
CONFIG_KEXEC_CORE=y
CONFIG_HAVE_OPROFILE=y
CONFIG_OPROFILE_NMI_TIMER=y
CONFIG_JUMP_LABEL=y
# CONFIG_STATIC_KEYS_SELFTEST is not set
# CONFIG_UPROBES is not set
# CONFIG_HAVE_64BIT_ALIGNED_ACCESS is not set
CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS=y
CONFIG_ARCH_USE_BUILTIN_BSWAP=y
CONFIG_HAVE_IOREMAP_PROT=y
CONFIG_HAVE_KPROBES=y
CONFIG_HAVE_KRETPROBES=y
CONFIG_HAVE_OPTPROBES=y
CONFIG_HAVE_KPROBES_ON_FTRACE=y
CONFIG_HAVE_NMI=y
CONFIG_HAVE_ARCH_TRACEHOOK=y
CONFIG_HAVE_DMA_CONTIGUOUS=y
CONFIG_GENERIC_SMP_IDLE_THREAD=y
CONFIG_ARCH_WANTS_DYNAMIC_TASK_STRUCT=y
CONFIG_HAVE_REGS_AND_STACK_ACCESS_API=y
CONFIG_HAVE_DMA_API_DEBUG=y
CONFIG_HAVE_HW_BREAKPOINT=y
CONFIG_HAVE_MIXED_BREAKPOINTS_REGS=y
CONFIG_HAVE_USER_RETURN_NOTIFIER=y
CONFIG_HAVE_PERF_EVENTS_NMI=y
CONFIG_HAVE_PERF_REGS=y
CONFIG_HAVE_PERF_USER_STACK_DUMP=y
CONFIG_HAVE_ARCH_JUMP_LABEL=y
CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG=y
CONFIG_HAVE_ALIGNED_STRUCT_PAGE=y
CONFIG_HAVE_CMPXCHG_LOCAL=y
CONFIG_HAVE_CMPXCHG_DOUBLE=y
CONFIG_HAVE_ARCH_SECCOMP_FILTER=y
CONFIG_HAVE_GCC_PLUGINS=y
# CONFIG_GCC_PLUGINS is not set
CONFIG_HAVE_CC_STACKPROTECTOR=y
# CONFIG_CC_STACKPROTECTOR is not set
CONFIG_CC_STACKPROTECTOR_NONE=y
# CONFIG_CC_STACKPROTECTOR_REGULAR is not set
# CONFIG_CC_STACKPROTECTOR_STRONG is not set
CONFIG_HAVE_ARCH_WITHIN_STACK_FRAMES=y
CONFIG_HAVE_CONTEXT_TRACKING=y
CONFIG_HAVE_VIRT_CPU_ACCOUNTING_GEN=y
CONFIG_HAVE_IRQ_TIME_ACCOUNTING=y
CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE=y
CONFIG_HAVE_ARCH_HUGE_VMAP=y
CONFIG_HAVE_ARCH_SOFT_DIRTY=y
CONFIG_MODULES_USE_ELF_RELA=y
CONFIG_HAVE_IRQ_EXIT_ON_IRQ_STACK=y
CONFIG_ARCH_HAS_ELF_RANDOMIZE=y
CONFIG_HAVE_ARCH_MMAP_RND_BITS=y
CONFIG_HAVE_EXIT_THREAD=y
CONFIG_ARCH_MMAP_RND_BITS=28
CONFIG_HAVE_COPY_THREAD_TLS=y
CONFIG_HAVE_STACK_VALIDATION=y
# CONFIG_HAVE_ARCH_HASH is not set
# CONFIG_ISA_BUS_API is not set
# CONFIG_CPU_NO_EFFICIENT_FFS is not set

#
# GCOV-based kernel profiling
#
CONFIG_GCOV_KERNEL=y
CONFIG_ARCH_HAS_GCOV_PROFILE_ALL=y
# CONFIG_GCOV_PROFILE_ALL is not set
CONFIG_GCOV_FORMAT_AUTODETECT=y
# CONFIG_GCOV_FORMAT_3_4 is not set
# CONFIG_GCOV_FORMAT_4_7 is not set
# CONFIG_HAVE_GENERIC_DMA_COHERENT is not set
CONFIG_SLABINFO=y
CONFIG_RT_MUTEXES=y
CONFIG_BASE_SMALL=0
# CONFIG_MODULES is not set
CONFIG_MODULES_TREE_LOOKUP=y
CONFIG_BLOCK=y
# CONFIG_BLK_DEV_BSG is not set
# CONFIG_BLK_DEV_BSGLIB is not set
# CONFIG_BLK_DEV_INTEGRITY is not set
# CONFIG_BLK_CMDLINE_PARSER is not set

#
# Partition Types
#
CONFIG_PARTITION_ADVANCED=y
# CONFIG_ACORN_PARTITION is not set
# CONFIG_AIX_PARTITION is not set
# CONFIG_OSF_PARTITION is not set
# CONFIG_AMIGA_PARTITION is not set
# CONFIG_ATARI_PARTITION is not set
CONFIG_MAC_PARTITION=y
CONFIG_MSDOS_PARTITION=y
# CONFIG_BSD_DISKLABEL is not set
# CONFIG_MINIX_SUBPARTITION is not set
# CONFIG_SOLARIS_X86_PARTITION is not set
# CONFIG_UNIXWARE_DISKLABEL is not set
# CONFIG_LDM_PARTITION is not set
# CONFIG_SGI_PARTITION is not set
# CONFIG_ULTRIX_PARTITION is not set
# CONFIG_SUN_PARTITION is not set
# CONFIG_KARMA_PARTITION is not set
CONFIG_EFI_PARTITION=y
# CONFIG_SYSV68_PARTITION is not set
# CONFIG_CMDLINE_PARTITION is not set

#
# IO Schedulers
#
CONFIG_IOSCHED_NOOP=y
# CONFIG_IOSCHED_DEADLINE is not set
# CONFIG_IOSCHED_CFQ is not set
CONFIG_DEFAULT_NOOP=y
CONFIG_DEFAULT_IOSCHED="noop"
CONFIG_UNINLINE_SPIN_UNLOCK=y
CONFIG_ARCH_SUPPORTS_ATOMIC_RMW=y
CONFIG_RWSEM_SPIN_ON_OWNER=y
CONFIG_LOCK_SPIN_ON_OWNER=y
CONFIG_ARCH_USE_QUEUED_SPINLOCKS=y
CONFIG_QUEUED_SPINLOCKS=y
CONFIG_ARCH_USE_QUEUED_RWLOCKS=y
CONFIG_QUEUED_RWLOCKS=y
# CONFIG_FREEZER is not set

#
# Processor type and features
#
CONFIG_ZONE_DMA=y
CONFIG_SMP=y
CONFIG_X86_FEATURE_NAMES=y
CONFIG_X86_FAST_FEATURE_TESTS=y
# CONFIG_X86_X2APIC is not set
CONFIG_X86_MPPARSE=y
# CONFIG_GOLDFISH is not set
# CONFIG_X86_EXTENDED_PLATFORM is not set
# CONFIG_X86_INTEL_LPSS is not set
# CONFIG_X86_AMD_PLATFORM_DEVICE is not set
CONFIG_IOSF_MBI=y
# CONFIG_IOSF_MBI_DEBUG is not set
CONFIG_SCHED_OMIT_FRAME_POINTER=y
CONFIG_HYPERVISOR_GUEST=y
CONFIG_PARAVIRT=y
# CONFIG_PARAVIRT_DEBUG is not set
CONFIG_PARAVIRT_SPINLOCKS=y
# CONFIG_QUEUED_LOCK_STAT is not set
# CONFIG_XEN is not set
CONFIG_KVM_GUEST=y
# CONFIG_KVM_DEBUG_FS is not set
# CONFIG_PARAVIRT_TIME_ACCOUNTING is not set
CONFIG_PARAVIRT_CLOCK=y
CONFIG_NO_BOOTMEM=y
# CONFIG_MK8 is not set
# CONFIG_MPSC is not set
CONFIG_MCORE2=y
# CONFIG_MATOM is not set
# CONFIG_GENERIC_CPU is not set
CONFIG_X86_INTERNODE_CACHE_SHIFT=6
CONFIG_X86_L1_CACHE_SHIFT=6
CONFIG_X86_INTEL_USERCOPY=y
CONFIG_X86_USE_PPRO_CHECKSUM=y
CONFIG_X86_P6_NOP=y
CONFIG_X86_TSC=y
CONFIG_X86_CMPXCHG64=y
CONFIG_X86_CMOV=y
CONFIG_X86_MINIMUM_CPU_FAMILY=64
CONFIG_X86_DEBUGCTLMSR=y
# CONFIG_PROCESSOR_SELECT is not set
CONFIG_CPU_SUP_INTEL=y
CONFIG_CPU_SUP_AMD=y
CONFIG_CPU_SUP_CENTAUR=y
CONFIG_HPET_TIMER=y
CONFIG_DMI=y
CONFIG_GART_IOMMU=y
# CONFIG_CALGARY_IOMMU is not set
CONFIG_SWIOTLB=y
CONFIG_IOMMU_HELPER=y
# CONFIG_MAXSMP is not set
CONFIG_NR_CPUS=4
# CONFIG_SCHED_SMT is not set
CONFIG_SCHED_MC=y
# CONFIG_PREEMPT_NONE is not set
# CONFIG_PREEMPT_VOLUNTARY is not set
CONFIG_PREEMPT=y
CONFIG_PREEMPT_COUNT=y
CONFIG_X86_LOCAL_APIC=y
CONFIG_X86_IO_APIC=y
# CONFIG_X86_REROUTE_FOR_BROKEN_BOOT_IRQS is not set
# CONFIG_X86_MCE is not set

#
# Performance monitoring
#
CONFIG_PERF_EVENTS_INTEL_UNCORE=y
CONFIG_PERF_EVENTS_INTEL_RAPL=y
CONFIG_PERF_EVENTS_INTEL_CSTATE=y
# CONFIG_PERF_EVENTS_AMD_POWER is not set
# CONFIG_VM86 is not set
CONFIG_X86_VSYSCALL_EMULATION=y
# CONFIG_I8K is not set
# CONFIG_MICROCODE is not set
# CONFIG_X86_MSR is not set
# CONFIG_X86_CPUID is not set
CONFIG_ARCH_PHYS_ADDR_T_64BIT=y
CONFIG_ARCH_DMA_ADDR_T_64BIT=y
# CONFIG_NUMA is not set
CONFIG_ARCH_SPARSEMEM_ENABLE=y
CONFIG_ARCH_SPARSEMEM_DEFAULT=y
CONFIG_ARCH_SELECT_MEMORY_MODEL=y
CONFIG_ARCH_PROC_KCORE_TEXT=y
CONFIG_ILLEGAL_POINTER_VALUE=0xdead000000000000
CONFIG_SELECT_MEMORY_MODEL=y
CONFIG_SPARSEMEM_MANUAL=y
CONFIG_SPARSEMEM=y
CONFIG_HAVE_MEMORY_PRESENT=y
CONFIG_SPARSEMEM_EXTREME=y
CONFIG_SPARSEMEM_VMEMMAP_ENABLE=y
CONFIG_SPARSEMEM_ALLOC_MEM_MAP_TOGETHER=y
CONFIG_SPARSEMEM_VMEMMAP=y
CONFIG_HAVE_MEMBLOCK=y
CONFIG_HAVE_MEMBLOCK_NODE_MAP=y
CONFIG_ARCH_DISCARD_MEMBLOCK=y
CONFIG_MEMORY_ISOLATION=y
# CONFIG_HAVE_BOOTMEM_INFO_NODE is not set
# CONFIG_MEMORY_HOTPLUG is not set
CONFIG_SPLIT_PTLOCK_CPUS=4
CONFIG_ARCH_ENABLE_SPLIT_PMD_PTLOCK=y
# CONFIG_COMPACTION is not set
CONFIG_MIGRATION=y
CONFIG_PHYS_ADDR_T_64BIT=y
# CONFIG_BOUNCE is not set
CONFIG_VIRT_TO_BUS=y
# CONFIG_KSM is not set
CONFIG_DEFAULT_MMAP_MIN_ADDR=65536
# CONFIG_TRANSPARENT_HUGEPAGE is not set
# CONFIG_CLEANCACHE is not set
CONFIG_CMA=y
CONFIG_CMA_DEBUG=y
# CONFIG_CMA_DEBUGFS is not set
CONFIG_CMA_AREAS=7
# CONFIG_ZPOOL is not set
# CONFIG_ZBUD is not set
# CONFIG_ZSMALLOC is not set
CONFIG_GENERIC_EARLY_IOREMAP=y
CONFIG_ARCH_SUPPORTS_DEFERRED_STRUCT_PAGE_INIT=y
# CONFIG_IDLE_PAGE_TRACKING is not set
# CONFIG_X86_PMEM_LEGACY is not set
# CONFIG_X86_CHECK_BIOS_CORRUPTION is not set
CONFIG_X86_RESERVE_LOW=64
CONFIG_MTRR=y
# CONFIG_MTRR_SANITIZER is not set
CONFIG_X86_PAT=y
CONFIG_ARCH_USES_PG_UNCACHED=y
CONFIG_ARCH_RANDOM=y
CONFIG_X86_SMAP=y
CONFIG_X86_INTEL_MPX=y
# CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS is not set
# CONFIG_EFI is not set
# CONFIG_SECCOMP is not set
CONFIG_HZ_100=y
# CONFIG_HZ_250 is not set
# CONFIG_HZ_300 is not set
# CONFIG_HZ_1000 is not set
CONFIG_HZ=100
CONFIG_SCHED_HRTICK=y
CONFIG_KEXEC=y
# CONFIG_KEXEC_FILE is not set
# CONFIG_CRASH_DUMP is not set
CONFIG_PHYSICAL_START=0x1000000
# CONFIG_RELOCATABLE is not set
CONFIG_PHYSICAL_ALIGN=0x1000000
# CONFIG_HOTPLUG_CPU is not set
# CONFIG_LEGACY_VSYSCALL_NATIVE is not set
CONFIG_LEGACY_VSYSCALL_EMULATE=y
# CONFIG_LEGACY_VSYSCALL_NONE is not set
# CONFIG_CMDLINE_BOOL is not set
# CONFIG_MODIFY_LDT_SYSCALL is not set
CONFIG_HAVE_LIVEPATCH=y
CONFIG_ARCH_ENABLE_MEMORY_HOTPLUG=y

#
# Power management and ACPI options
#
# CONFIG_SUSPEND is not set
# CONFIG_PM is not set
CONFIG_ACPI=y
CONFIG_ACPI_LEGACY_TABLES_LOOKUP=y
CONFIG_ARCH_MIGHT_HAVE_ACPI_PDC=y
CONFIG_ACPI_SYSTEM_POWER_STATES_SUPPORT=y
# CONFIG_ACPI_DEBUGGER is not set
# CONFIG_ACPI_PROCFS_POWER is not set
CONFIG_ACPI_REV_OVERRIDE_POSSIBLE=y
# CONFIG_ACPI_EC_DEBUGFS is not set
# CONFIG_ACPI_AC is not set
# CONFIG_ACPI_BATTERY is not set
CONFIG_ACPI_BUTTON=y
# CONFIG_ACPI_DOCK is not set
CONFIG_ACPI_PROCESSOR_CSTATE=y
# CONFIG_ACPI_PROCESSOR is not set
# CONFIG_ACPI_CUSTOM_DSDT is not set
CONFIG_ARCH_HAS_ACPI_TABLE_UPGRADE=y
# CONFIG_ACPI_DEBUG is not set
# CONFIG_ACPI_PCI_SLOT is not set
CONFIG_X86_PM_TIMER=y
# CONFIG_ACPI_CONTAINER is not set
CONFIG_ACPI_HOTPLUG_IOAPIC=y
# CONFIG_ACPI_SBS is not set
# CONFIG_ACPI_HED is not set
# CONFIG_ACPI_CUSTOM_METHOD is not set
# CONFIG_ACPI_REDUCED_HARDWARE_ONLY is not set
# CONFIG_ACPI_NFIT is not set
CONFIG_HAVE_ACPI_APEI=y
CONFIG_HAVE_ACPI_APEI_NMI=y
# CONFIG_ACPI_APEI is not set
# CONFIG_DPTF_POWER is not set
# CONFIG_PMIC_OPREGION is not set
# CONFIG_ACPI_CONFIGFS is not set
# CONFIG_SFI is not set

#
# CPU Frequency scaling
#
# CONFIG_CPU_FREQ is not set

#
# CPU Idle
#
CONFIG_CPU_IDLE=y
CONFIG_CPU_IDLE_GOV_LADDER=y
CONFIG_CPU_IDLE_GOV_MENU=y
# CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED is not set
# CONFIG_INTEL_IDLE is not set

#
# Memory power savings
#
# CONFIG_I7300_IDLE is not set

#
# Bus options (PCI etc.)
#
CONFIG_PCI=y
CONFIG_PCI_DIRECT=y
# CONFIG_PCI_MMCONFIG is not set
CONFIG_PCI_DOMAINS=y
# CONFIG_PCI_CNB20LE_QUIRK is not set
# CONFIG_PCIEPORTBUS is not set
CONFIG_PCI_BUS_ADDR_T_64BIT=y
# CONFIG_PCI_MSI is not set
# CONFIG_PCI_DEBUG is not set
# CONFIG_PCI_REALLOC_ENABLE_AUTO is not set
# CONFIG_PCI_STUB is not set
# CONFIG_HT_IRQ is not set
# CONFIG_PCI_IOV is not set
# CONFIG_PCI_PRI is not set
# CONFIG_PCI_PASID is not set
CONFIG_PCI_LABEL=y
# CONFIG_HOTPLUG_PCI is not set

#
# PCI host controller drivers
#
# CONFIG_ISA_BUS is not set
# CONFIG_ISA_DMA_API is not set
CONFIG_AMD_NB=y
# CONFIG_PCCARD is not set
# CONFIG_RAPIDIO is not set
# CONFIG_X86_SYSFB is not set

#
# Executable file formats / Emulations
#
CONFIG_BINFMT_ELF=y
CONFIG_ELFCORE=y
CONFIG_CORE_DUMP_DEFAULT_ELF_HEADERS=y
CONFIG_BINFMT_SCRIPT=y
# CONFIG_HAVE_AOUT is not set
# CONFIG_BINFMT_MISC is not set
CONFIG_COREDUMP=y
# CONFIG_IA32_EMULATION is not set
# CONFIG_X86_X32 is not set
CONFIG_X86_DEV_DMA_OPS=y
CONFIG_PMC_ATOM=y
CONFIG_NET=y
CONFIG_NET_INGRESS=y

#
# Networking options
#
CONFIG_PACKET=y
# CONFIG_PACKET_DIAG is not set
CONFIG_UNIX=y
# CONFIG_UNIX_DIAG is not set
CONFIG_XFRM=y
# CONFIG_XFRM_USER is not set
# CONFIG_XFRM_SUB_POLICY is not set
# CONFIG_XFRM_MIGRATE is not set
# CONFIG_XFRM_STATISTICS is not set
# CONFIG_NET_KEY is not set
CONFIG_INET=y
CONFIG_IP_MULTICAST=y
CONFIG_IP_ADVANCED_ROUTER=y
# CONFIG_IP_FIB_TRIE_STATS is not set
CONFIG_IP_MULTIPLE_TABLES=y
# CONFIG_IP_ROUTE_MULTIPATH is not set
# CONFIG_IP_ROUTE_VERBOSE is not set
# CONFIG_IP_PNP is not set
# CONFIG_NET_IPIP is not set
# CONFIG_NET_IPGRE_DEMUX is not set
CONFIG_NET_IP_TUNNEL=y
# CONFIG_IP_MROUTE is not set
# CONFIG_SYN_COOKIES is not set
# CONFIG_NET_UDP_TUNNEL is not set
# CONFIG_NET_FOU is not set
# CONFIG_NET_FOU_IP_TUNNELS is not set
# CONFIG_INET_AH is not set
# CONFIG_INET_ESP is not set
# CONFIG_INET_IPCOMP is not set
# CONFIG_INET_XFRM_TUNNEL is not set
CONFIG_INET_TUNNEL=y
# CONFIG_INET_XFRM_MODE_TRANSPORT is not set
# CONFIG_INET_XFRM_MODE_TUNNEL is not set
# CONFIG_INET_XFRM_MODE_BEET is not set
# CONFIG_INET_DIAG is not set
# CONFIG_TCP_CONG_ADVANCED is not set
CONFIG_TCP_CONG_CUBIC=y
CONFIG_DEFAULT_TCP_CONG="cubic"
# CONFIG_TCP_MD5SIG is not set
CONFIG_IPV6=y
# CONFIG_IPV6_ROUTER_PREF is not set
# CONFIG_IPV6_OPTIMISTIC_DAD is not set
# CONFIG_INET6_AH is not set
# CONFIG_INET6_ESP is not set
# CONFIG_INET6_IPCOMP is not set
# CONFIG_IPV6_MIP6 is not set
# CONFIG_IPV6_ILA is not set
# CONFIG_INET6_XFRM_TUNNEL is not set
# CONFIG_INET6_TUNNEL is not set
CONFIG_INET6_XFRM_MODE_TRANSPORT=y
CONFIG_INET6_XFRM_MODE_TUNNEL=y
CONFIG_INET6_XFRM_MODE_BEET=y
# CONFIG_INET6_XFRM_MODE_ROUTEOPTIMIZATION is not set
# CONFIG_IPV6_VTI is not set
CONFIG_IPV6_SIT=y
# CONFIG_IPV6_SIT_6RD is not set
CONFIG_IPV6_NDISC_NODETYPE=y
# CONFIG_IPV6_TUNNEL is not set
# CONFIG_IPV6_FOU is not set
# CONFIG_IPV6_FOU_TUNNEL is not set
# CONFIG_IPV6_MULTIPLE_TABLES is not set
# CONFIG_IPV6_MROUTE is not set
# CONFIG_NETWORK_SECMARK is not set
# CONFIG_NET_PTP_CLASSIFY is not set
# CONFIG_NETWORK_PHY_TIMESTAMPING is not set
CONFIG_NETFILTER=y
# CONFIG_NETFILTER_DEBUG is not set
# CONFIG_NETFILTER_ADVANCED is not set

#
# Core Netfilter Configuration
#
CONFIG_NETFILTER_INGRESS=y
CONFIG_NETFILTER_NETLINK=y
CONFIG_NETFILTER_NETLINK_LOG=y
# CONFIG_NF_CONNTRACK is not set
CONFIG_NF_LOG_COMMON=y
# CONFIG_NF_TABLES is not set
CONFIG_NETFILTER_XTABLES=y

#
# Xtables combined modules
#
# CONFIG_NETFILTER_XT_MARK is not set

#
# Xtables targets
#
# CONFIG_NETFILTER_XT_TARGET_LOG is not set
# CONFIG_NETFILTER_XT_TARGET_NFLOG is not set
# CONFIG_NETFILTER_XT_TARGET_TCPMSS is not set

#
# Xtables matches
#
# CONFIG_NETFILTER_XT_MATCH_ADDRTYPE is not set
# CONFIG_NETFILTER_XT_MATCH_POLICY is not set
# CONFIG_IP_SET is not set
# CONFIG_IP_VS is not set

#
# IP: Netfilter Configuration
#
# CONFIG_NF_DEFRAG_IPV4 is not set
# CONFIG_NF_DUP_IPV4 is not set
# CONFIG_NF_LOG_ARP is not set
# CONFIG_NF_LOG_IPV4 is not set
CONFIG_NF_REJECT_IPV4=y
CONFIG_IP_NF_IPTABLES=y
CONFIG_IP_NF_FILTER=y
CONFIG_IP_NF_TARGET_REJECT=y
CONFIG_IP_NF_MANGLE=y
# CONFIG_IP_NF_RAW is not set

#
# IPv6: Netfilter Configuration
#
# CONFIG_NF_DEFRAG_IPV6 is not set
# CONFIG_NF_DUP_IPV6 is not set
CONFIG_NF_REJECT_IPV6=y
CONFIG_NF_LOG_IPV6=y
CONFIG_IP6_NF_IPTABLES=y
CONFIG_IP6_NF_MATCH_IPV6HEADER=y
CONFIG_IP6_NF_FILTER=y
CONFIG_IP6_NF_TARGET_REJECT=y
CONFIG_IP6_NF_MANGLE=y
# CONFIG_IP6_NF_RAW is not set
CONFIG_BRIDGE_NF_EBTABLES=y
CONFIG_BRIDGE_EBT_BROUTE=y
CONFIG_BRIDGE_EBT_T_FILTER=y
CONFIG_BRIDGE_EBT_T_NAT=y
CONFIG_BRIDGE_EBT_802_3=y
CONFIG_BRIDGE_EBT_AMONG=y
CONFIG_BRIDGE_EBT_ARP=y
CONFIG_BRIDGE_EBT_IP=y
CONFIG_BRIDGE_EBT_IP6=y
CONFIG_BRIDGE_EBT_LIMIT=y
CONFIG_BRIDGE_EBT_MARK=y
CONFIG_BRIDGE_EBT_PKTTYPE=y
CONFIG_BRIDGE_EBT_STP=y
CONFIG_BRIDGE_EBT_VLAN=y
CONFIG_BRIDGE_EBT_ARPREPLY=y
CONFIG_BRIDGE_EBT_DNAT=y
CONFIG_BRIDGE_EBT_MARK_T=y
CONFIG_BRIDGE_EBT_REDIRECT=y
CONFIG_BRIDGE_EBT_SNAT=y
CONFIG_BRIDGE_EBT_LOG=y
CONFIG_BRIDGE_EBT_NFLOG=y
# CONFIG_IP_DCCP is not set
# CONFIG_IP_SCTP is not set
# CONFIG_RDS is not set
# CONFIG_TIPC is not set
# CONFIG_ATM is not set
# CONFIG_L2TP is not set
CONFIG_STP=y
CONFIG_BRIDGE=y
CONFIG_BRIDGE_IGMP_SNOOPING=y
CONFIG_HAVE_NET_DSA=y
# CONFIG_VLAN_8021Q is not set
# CONFIG_DECNET is not set
CONFIG_LLC=y
# CONFIG_LLC2 is not set
# CONFIG_IPX is not set
# CONFIG_ATALK is not set
# CONFIG_X25 is not set
# CONFIG_LAPB is not set
# CONFIG_PHONET is not set
# CONFIG_6LOWPAN is not set
# CONFIG_IEEE802154 is not set
# CONFIG_NET_SCHED is not set
# CONFIG_DCB is not set
# CONFIG_BATMAN_ADV is not set
# CONFIG_OPENVSWITCH is not set
# CONFIG_VSOCKETS is not set
# CONFIG_NETLINK_DIAG is not set
# CONFIG_MPLS is not set
# CONFIG_HSR is not set
# CONFIG_NET_SWITCHDEV is not set
# CONFIG_NET_L3_MASTER_DEV is not set
# CONFIG_NET_NCSI is not set
CONFIG_RPS=y
CONFIG_RFS_ACCEL=y
CONFIG_XPS=y
# CONFIG_SOCK_CGROUP_DATA is not set
CONFIG_NET_RX_BUSY_POLL=y
CONFIG_BQL=y
CONFIG_NET_FLOW_LIMIT=y

#
# Network testing
#
# CONFIG_NET_PKTGEN is not set
CONFIG_NET_DROP_MONITOR=y
# CONFIG_HAMRADIO is not set
# CONFIG_CAN is not set
# CONFIG_IRDA is not set
# CONFIG_BT is not set
# CONFIG_AF_RXRPC is not set
# CONFIG_AF_KCM is not set
# CONFIG_STREAM_PARSER is not set
CONFIG_FIB_RULES=y
CONFIG_WIRELESS=y
CONFIG_WEXT_CORE=y
CONFIG_WEXT_PROC=y
CONFIG_CFG80211=y
CONFIG_NL80211_TESTMODE=y
CONFIG_CFG80211_DEVELOPER_WARNINGS=y
# CONFIG_CFG80211_CERTIFICATION_ONUS is not set
CONFIG_CFG80211_DEFAULT_PS=y
CONFIG_CFG80211_DEBUGFS=y
# CONFIG_CFG80211_INTERNAL_REGDB is not set
CONFIG_CFG80211_CRDA_SUPPORT=y
CONFIG_CFG80211_WEXT=y
# CONFIG_LIB80211 is not set
CONFIG_MAC80211=y
CONFIG_MAC80211_HAS_RC=y
CONFIG_MAC80211_RC_MINSTREL=y
CONFIG_MAC80211_RC_MINSTREL_HT=y
CONFIG_MAC80211_RC_MINSTREL_VHT=y
CONFIG_MAC80211_RC_DEFAULT_MINSTREL=y
CONFIG_MAC80211_RC_DEFAULT="minstrel_ht"
CONFIG_MAC80211_MESH=y
CONFIG_MAC80211_LEDS=y
CONFIG_MAC80211_DEBUGFS=y
CONFIG_MAC80211_MESSAGE_TRACING=y
CONFIG_MAC80211_DEBUG_MENU=y
CONFIG_MAC80211_NOINLINE=y
CONFIG_MAC80211_VERBOSE_DEBUG=y
CONFIG_MAC80211_MLME_DEBUG=y
CONFIG_MAC80211_STA_DEBUG=y
CONFIG_MAC80211_HT_DEBUG=y
CONFIG_MAC80211_OCB_DEBUG=y
CONFIG_MAC80211_IBSS_DEBUG=y
CONFIG_MAC80211_PS_DEBUG=y
CONFIG_MAC80211_MPL_DEBUG=y
CONFIG_MAC80211_MPATH_DEBUG=y
CONFIG_MAC80211_MHWMP_DEBUG=y
CONFIG_MAC80211_MESH_SYNC_DEBUG=y
CONFIG_MAC80211_MESH_CSA_DEBUG=y
CONFIG_MAC80211_MESH_PS_DEBUG=y
CONFIG_MAC80211_TDLS_DEBUG=y
CONFIG_MAC80211_DEBUG_COUNTERS=y
CONFIG_MAC80211_STA_HASH_MAX_SIZE=0
# CONFIG_WIMAX is not set
CONFIG_RFKILL=y
CONFIG_RFKILL_LEDS=y
# CONFIG_RFKILL_INPUT is not set
CONFIG_NET_9P=y
CONFIG_NET_9P_VIRTIO=y
# CONFIG_NET_9P_DEBUG is not set
# CONFIG_CAIF is not set
# CONFIG_CEPH_LIB is not set
# CONFIG_NFC is not set
# CONFIG_LWTUNNEL is not set
CONFIG_DST_CACHE=y
# CONFIG_NET_DEVLINK is not set
CONFIG_MAY_USE_DEVLINK=y
CONFIG_HAVE_EBPF_JIT=y

#
# Device Drivers
#

#
# Generic Driver Options
#
CONFIG_UEVENT_HELPER=y
CONFIG_UEVENT_HELPER_PATH="/sbin/hotplug"
# CONFIG_DEVTMPFS is not set
CONFIG_STANDALONE=y
CONFIG_PREVENT_FIRMWARE_BUILD=y
CONFIG_FW_LOADER=y
CONFIG_FIRMWARE_IN_KERNEL=y
CONFIG_EXTRA_FIRMWARE=""
# CONFIG_FW_LOADER_USER_HELPER_FALLBACK is not set
CONFIG_ALLOW_DEV_COREDUMP=y
# CONFIG_DEBUG_DRIVER is not set
# CONFIG_DEBUG_DEVRES is not set
# CONFIG_SYS_HYPERVISOR is not set
# CONFIG_GENERIC_CPU_DEVICES is not set
CONFIG_GENERIC_CPU_AUTOPROBE=y
# CONFIG_DMA_SHARED_BUFFER is not set
# CONFIG_DMA_CMA is not set

#
# Bus devices
#
# CONFIG_CONNECTOR is not set
# CONFIG_MTD is not set
# CONFIG_OF is not set
CONFIG_ARCH_MIGHT_HAVE_PC_PARPORT=y
# CONFIG_PARPORT is not set
CONFIG_PNP=y
# CONFIG_PNP_DEBUG_MESSAGES is not set

#
# Protocols
#
CONFIG_PNPACPI=y
CONFIG_BLK_DEV=y
# CONFIG_BLK_DEV_NULL_BLK is not set
# CONFIG_BLK_DEV_PCIESSD_MTIP32XX is not set
# CONFIG_BLK_CPQ_CISS_DA is not set
# CONFIG_BLK_DEV_DAC960 is not set
# CONFIG_BLK_DEV_UMEM is not set
# CONFIG_BLK_DEV_COW_COMMON is not set
# CONFIG_BLK_DEV_LOOP is not set
# CONFIG_BLK_DEV_DRBD is not set
# CONFIG_BLK_DEV_NBD is not set
# CONFIG_BLK_DEV_SKD is not set
# CONFIG_BLK_DEV_SX8 is not set
# CONFIG_BLK_DEV_RAM is not set
# CONFIG_CDROM_PKTCDVD is not set
# CONFIG_ATA_OVER_ETH is not set
CONFIG_VIRTIO_BLK=y
# CONFIG_BLK_DEV_HD is not set
# CONFIG_BLK_DEV_RBD is not set
# CONFIG_BLK_DEV_RSXX is not set
# CONFIG_BLK_DEV_NVME is not set
# CONFIG_NVME_TARGET is not set

#
# Misc devices
#
# CONFIG_SENSORS_LIS3LV02D is not set
# CONFIG_AD525X_DPOT is not set
# CONFIG_DUMMY_IRQ is not set
# CONFIG_IBM_ASM is not set
# CONFIG_PHANTOM is not set
# CONFIG_SGI_IOC4 is not set
# CONFIG_TIFM_CORE is not set
# CONFIG_ICS932S401 is not set
# CONFIG_ENCLOSURE_SERVICES is not set
# CONFIG_HP_ILO is not set
# CONFIG_APDS9802ALS is not set
# CONFIG_ISL29003 is not set
# CONFIG_ISL29020 is not set
# CONFIG_SENSORS_TSL2550 is not set
# CONFIG_SENSORS_BH1780 is not set
# CONFIG_SENSORS_BH1770 is not set
# CONFIG_SENSORS_APDS990X is not set
# CONFIG_HMC6352 is not set
# CONFIG_DS1682 is not set
# CONFIG_BMP085_I2C is not set
# CONFIG_USB_SWITCH_FSA9480 is not set
# CONFIG_SRAM is not set
# CONFIG_C2PORT is not set

#
# EEPROM support
#
# CONFIG_EEPROM_AT24 is not set
# CONFIG_EEPROM_LEGACY is not set
# CONFIG_EEPROM_MAX6875 is not set
# CONFIG_EEPROM_93CX6 is not set
# CONFIG_CB710_CORE is not set

#
# Texas Instruments shared transport line discipline
#
# CONFIG_SENSORS_LIS3_I2C is not set

#
# Altera FPGA firmware download module
#
# CONFIG_ALTERA_STAPL is not set
# CONFIG_INTEL_MEI is not set
# CONFIG_INTEL_MEI_ME is not set
# CONFIG_INTEL_MEI_TXE is not set
# CONFIG_VMWARE_VMCI is not set

#
# Intel MIC Bus Driver
#
# CONFIG_INTEL_MIC_BUS is not set

#
# SCIF Bus Driver
#
# CONFIG_SCIF_BUS is not set

#
# VOP Bus Driver
#
# CONFIG_VOP_BUS is not set

#
# Intel MIC Host Driver
#

#
# Intel MIC Card Driver
#

#
# SCIF Driver
#

#
# Intel MIC Coprocessor State Management (COSM) Drivers
#

#
# VOP Driver
#
# CONFIG_GENWQE is not set
# CONFIG_ECHO is not set
# CONFIG_CXL_BASE is not set
# CONFIG_CXL_AFU_DRIVER_OPS is not set
CONFIG_HAVE_IDE=y
# CONFIG_IDE is not set

#
# SCSI device support
#
CONFIG_SCSI_MOD=y
# CONFIG_RAID_ATTRS is not set
# CONFIG_SCSI is not set
# CONFIG_SCSI_DMA is not set
# CONFIG_SCSI_NETLINK is not set
# CONFIG_ATA is not set
# CONFIG_MD is not set
# CONFIG_FUSION is not set

#
# IEEE 1394 (FireWire) support
#
# CONFIG_FIREWIRE is not set
# CONFIG_FIREWIRE_NOSY is not set
# CONFIG_MACINTOSH_DRIVERS is not set
CONFIG_NETDEVICES=y
CONFIG_NET_CORE=y
# CONFIG_BONDING is not set
# CONFIG_DUMMY is not set
# CONFIG_EQUALIZER is not set
# CONFIG_NET_TEAM is not set
# CONFIG_MACVLAN is not set
# CONFIG_IPVLAN is not set
# CONFIG_VXLAN is not set
# CONFIG_MACSEC is not set
# CONFIG_NETCONSOLE is not set
# CONFIG_NETPOLL is not set
# CONFIG_NET_POLL_CONTROLLER is not set
# CONFIG_TUN is not set
# CONFIG_TUN_VNET_CROSS_LE is not set
# CONFIG_VETH is not set
CONFIG_VIRTIO_NET=y
# CONFIG_NLMON is not set
# CONFIG_ARCNET is not set

#
# CAIF transport drivers
#

#
# Distributed Switch Architecture drivers
#
# CONFIG_ETHERNET is not set
# CONFIG_FDDI is not set
# CONFIG_HIPPI is not set
# CONFIG_NET_SB1000 is not set
# CONFIG_PHYLIB is not set
# CONFIG_PPP is not set
# CONFIG_SLIP is not set

#
# Host-side USB support is needed for USB Network Adapter support
#
CONFIG_WLAN=y
CONFIG_WLAN_VENDOR_ADMTEK=y
# CONFIG_ADM8211 is not set
CONFIG_WLAN_VENDOR_ATH=y
# CONFIG_ATH_DEBUG is not set
# CONFIG_ATH5K is not set
# CONFIG_ATH5K_PCI is not set
# CONFIG_ATH9K is not set
# CONFIG_ATH6KL is not set
# CONFIG_WIL6210 is not set
# CONFIG_ATH10K is not set
# CONFIG_WCN36XX is not set
CONFIG_WLAN_VENDOR_ATMEL=y
# CONFIG_ATMEL is not set
CONFIG_WLAN_VENDOR_BROADCOM=y
# CONFIG_B43 is not set
# CONFIG_B43LEGACY is not set
# CONFIG_BRCMSMAC is not set
# CONFIG_BRCMFMAC is not set
CONFIG_WLAN_VENDOR_CISCO=y
CONFIG_WLAN_VENDOR_INTEL=y
# CONFIG_IPW2100 is not set
# CONFIG_IPW2200 is not set
# CONFIG_IWL4965 is not set
# CONFIG_IWL3945 is not set
# CONFIG_IWLWIFI is not set
CONFIG_WLAN_VENDOR_INTERSIL=y
# CONFIG_HOSTAP is not set
# CONFIG_HERMES is not set
# CONFIG_P54_COMMON is not set
# CONFIG_PRISM54 is not set
CONFIG_WLAN_VENDOR_MARVELL=y
# CONFIG_LIBERTAS is not set
# CONFIG_LIBERTAS_THINFIRM is not set
# CONFIG_MWIFIEX is not set
# CONFIG_MWL8K is not set
CONFIG_WLAN_VENDOR_MEDIATEK=y
CONFIG_WLAN_VENDOR_RALINK=y
# CONFIG_RT2X00 is not set
CONFIG_WLAN_VENDOR_REALTEK=y
# CONFIG_RTL8180 is not set
CONFIG_RTL_CARDS=y
# CONFIG_RTL8192CE is not set
# CONFIG_RTL8192SE is not set
# CONFIG_RTL8192DE is not set
# CONFIG_RTL8723AE is not set
# CONFIG_RTL8723BE is not set
# CONFIG_RTL8188EE is not set
# CONFIG_RTL8192EE is not set
# CONFIG_RTL8821AE is not set
CONFIG_WLAN_VENDOR_RSI=y
# CONFIG_RSI_91X is not set
CONFIG_WLAN_VENDOR_ST=y
# CONFIG_CW1200 is not set
CONFIG_WLAN_VENDOR_TI=y
# CONFIG_WL1251 is not set
# CONFIG_WL12XX is not set
# CONFIG_WL18XX is not set
# CONFIG_WLCORE is not set
CONFIG_WLAN_VENDOR_ZYDAS=y
CONFIG_MAC80211_HWSIM=y

#
# Enable WiMAX (Networking options) to see the WiMAX drivers
#
# CONFIG_WAN is not set
# CONFIG_VMXNET3 is not set
# CONFIG_FUJITSU_ES is not set
# CONFIG_ISDN is not set
# CONFIG_NVM is not set

#
# Input device support
#
CONFIG_INPUT=y
# CONFIG_INPUT_LEDS is not set
# CONFIG_INPUT_FF_MEMLESS is not set
# CONFIG_INPUT_POLLDEV is not set
# CONFIG_INPUT_SPARSEKMAP is not set
# CONFIG_INPUT_MATRIXKMAP is not set

#
# Userland interfaces
#
# CONFIG_INPUT_MOUSEDEV is not set
# CONFIG_INPUT_JOYDEV is not set
CONFIG_INPUT_EVDEV=y
# CONFIG_INPUT_EVBUG is not set

#
# Input Device Drivers
#
# CONFIG_INPUT_KEYBOARD is not set
# CONFIG_INPUT_MOUSE is not set
# CONFIG_INPUT_JOYSTICK is not set
# CONFIG_INPUT_TABLET is not set
# CONFIG_INPUT_TOUCHSCREEN is not set
# CONFIG_INPUT_MISC is not set
# CONFIG_RMI4_CORE is not set

#
# Hardware I/O ports
#
CONFIG_SERIO=y
CONFIG_ARCH_MIGHT_HAVE_PC_SERIO=y
CONFIG_SERIO_I8042=y
CONFIG_SERIO_SERPORT=y
# CONFIG_SERIO_CT82C710 is not set
# CONFIG_SERIO_PCIPS2 is not set
# CONFIG_SERIO_LIBPS2 is not set
# CONFIG_SERIO_RAW is not set
# CONFIG_SERIO_ALTERA_PS2 is not set
# CONFIG_SERIO_PS2MULT is not set
# CONFIG_SERIO_ARC_PS2 is not set
# CONFIG_USERIO is not set
# CONFIG_GAMEPORT is not set

#
# Character devices
#
CONFIG_TTY=y
CONFIG_VT=y
CONFIG_CONSOLE_TRANSLATIONS=y
CONFIG_VT_CONSOLE=y
CONFIG_HW_CONSOLE=y
CONFIG_VT_HW_CONSOLE_BINDING=y
CONFIG_UNIX98_PTYS=y
# CONFIG_LEGACY_PTYS is not set
# CONFIG_SERIAL_NONSTANDARD is not set
# CONFIG_NOZOMI is not set
# CONFIG_N_GSM is not set
# CONFIG_TRACE_SINK is not set
CONFIG_DEVMEM=y
# CONFIG_DEVKMEM is not set

#
# Serial drivers
#
CONFIG_SERIAL_EARLYCON=y
CONFIG_SERIAL_8250=y
CONFIG_SERIAL_8250_DEPRECATED_OPTIONS=y
# CONFIG_SERIAL_8250_PNP is not set
# CONFIG_SERIAL_8250_FINTEK is not set
CONFIG_SERIAL_8250_CONSOLE=y
CONFIG_SERIAL_8250_PCI=y
CONFIG_SERIAL_8250_NR_UARTS=4
CONFIG_SERIAL_8250_RUNTIME_UARTS=4
# CONFIG_SERIAL_8250_EXTENDED is not set
# CONFIG_SERIAL_8250_FSL is not set
# CONFIG_SERIAL_8250_DW is not set
# CONFIG_SERIAL_8250_RT288X is not set
# CONFIG_SERIAL_8250_MID is not set
# CONFIG_SERIAL_8250_MOXA is not set

#
# Non-8250 serial port support
#
# CONFIG_SERIAL_UARTLITE is not set
CONFIG_SERIAL_CORE=y
CONFIG_SERIAL_CORE_CONSOLE=y
# CONFIG_SERIAL_JSM is not set
# CONFIG_SERIAL_SCCNXP is not set
# CONFIG_SERIAL_SC16IS7XX is not set
# CONFIG_SERIAL_ALTERA_JTAGUART is not set
# CONFIG_SERIAL_ALTERA_UART is not set
# CONFIG_SERIAL_ARC is not set
# CONFIG_SERIAL_RP2 is not set
# CONFIG_SERIAL_FSL_LPUART is not set
# CONFIG_TTY_PRINTK is not set
CONFIG_HVC_DRIVER=y
CONFIG_VIRTIO_CONSOLE=y
# CONFIG_IPMI_HANDLER is not set
# CONFIG_HW_RANDOM is not set
# CONFIG_NVRAM is not set
# CONFIG_R3964 is not set
# CONFIG_APPLICOM is not set
# CONFIG_MWAVE is not set
# CONFIG_RAW_DRIVER is not set
# CONFIG_HPET is not set
# CONFIG_HANGCHECK_TIMER is not set
# CONFIG_TCG_TPM is not set
# CONFIG_TELCLOCK is not set
CONFIG_DEVPORT=y
# CONFIG_XILLYBUS is not set

#
# I2C support
#
CONFIG_I2C=y
CONFIG_ACPI_I2C_OPREGION=y
CONFIG_I2C_BOARDINFO=y
CONFIG_I2C_COMPAT=y
# CONFIG_I2C_CHARDEV is not set
# CONFIG_I2C_MUX is not set
CONFIG_I2C_HELPER_AUTO=y

#
# I2C Hardware Bus support
#

#
# PC SMBus host controller drivers
#
# CONFIG_I2C_ALI1535 is not set
# CONFIG_I2C_ALI1563 is not set
# CONFIG_I2C_ALI15X3 is not set
# CONFIG_I2C_AMD756 is not set
# CONFIG_I2C_AMD8111 is not set
# CONFIG_I2C_I801 is not set
# CONFIG_I2C_ISCH is not set
# CONFIG_I2C_ISMT is not set
# CONFIG_I2C_PIIX4 is not set
# CONFIG_I2C_NFORCE2 is not set
# CONFIG_I2C_SIS5595 is not set
# CONFIG_I2C_SIS630 is not set
# CONFIG_I2C_SIS96X is not set
# CONFIG_I2C_VIA is not set
# CONFIG_I2C_VIAPRO is not set

#
# ACPI drivers
#
# CONFIG_I2C_SCMI is not set

#
# I2C system bus drivers (mostly embedded / system-on-chip)
#
# CONFIG_I2C_DESIGNWARE_PCI is not set
# CONFIG_I2C_OCORES is not set
# CONFIG_I2C_PCA_PLATFORM is not set
# CONFIG_I2C_PXA_PCI is not set
# CONFIG_I2C_SIMTEC is not set
# CONFIG_I2C_XILINX is not set

#
# External I2C/SMBus adapter drivers
#
# CONFIG_I2C_PARPORT_LIGHT is not set
# CONFIG_I2C_TAOS_EVM is not set

#
# Other I2C/SMBus bus drivers
#
# CONFIG_I2C_SLAVE is not set
# CONFIG_I2C_DEBUG_CORE is not set
# CONFIG_I2C_DEBUG_ALGO is not set
# CONFIG_I2C_DEBUG_BUS is not set
# CONFIG_SPI is not set
# CONFIG_SPMI is not set
# CONFIG_HSI is not set

#
# PPS support
#
# CONFIG_PPS is not set

#
# PPS generators support
#

#
# PTP clock support
#
# CONFIG_PTP_1588_CLOCK is not set

#
# Enable PHYLIB and NETWORK_PHY_TIMESTAMPING to see the additional clocks.
#
# CONFIG_GPIOLIB is not set
# CONFIG_W1 is not set
CONFIG_POWER_SUPPLY=y
# CONFIG_POWER_SUPPLY_DEBUG is not set
# CONFIG_PDA_POWER is not set
# CONFIG_TEST_POWER is not set
# CONFIG_BATTERY_DS2780 is not set
# CONFIG_BATTERY_DS2781 is not set
# CONFIG_BATTERY_DS2782 is not set
# CONFIG_BATTERY_SBS is not set
# CONFIG_BATTERY_BQ27XXX is not set
# CONFIG_BATTERY_MAX17040 is not set
# CONFIG_BATTERY_MAX17042 is not set
# CONFIG_CHARGER_MAX8903 is not set
# CONFIG_CHARGER_LP8727 is not set
# CONFIG_CHARGER_BQ2415X is not set
# CONFIG_CHARGER_SMB347 is not set
# CONFIG_BATTERY_GAUGE_LTC2941 is not set
# CONFIG_POWER_RESET is not set
# CONFIG_POWER_AVS is not set
# CONFIG_HWMON is not set
# CONFIG_THERMAL is not set
# CONFIG_WATCHDOG is not set
CONFIG_SSB_POSSIBLE=y

#
# Sonics Silicon Backplane
#
# CONFIG_SSB is not set
CONFIG_BCMA_POSSIBLE=y

#
# Broadcom specific AMBA
#
# CONFIG_BCMA is not set

#
# Multifunction device drivers
#
# CONFIG_MFD_CORE is not set
# CONFIG_MFD_AS3711 is not set
# CONFIG_PMIC_ADP5520 is not set
# CONFIG_MFD_BCM590XX is not set
# CONFIG_MFD_AXP20X_I2C is not set
# CONFIG_MFD_CROS_EC is not set
# CONFIG_PMIC_DA903X is not set
# CONFIG_MFD_DA9052_I2C is not set
# CONFIG_MFD_DA9055 is not set
# CONFIG_MFD_DA9062 is not set
# CONFIG_MFD_DA9063 is not set
# CONFIG_MFD_DA9150 is not set
# CONFIG_MFD_MC13XXX_I2C is not set
# CONFIG_HTC_PASIC3 is not set
# CONFIG_LPC_ICH is not set
# CONFIG_LPC_SCH is not set
# CONFIG_MFD_INTEL_LPSS_ACPI is not set
# CONFIG_MFD_INTEL_LPSS_PCI is not set
# CONFIG_MFD_JANZ_CMODIO is not set
# CONFIG_MFD_KEMPLD is not set
# CONFIG_MFD_88PM800 is not set
# CONFIG_MFD_88PM805 is not set
# CONFIG_MFD_88PM860X is not set
# CONFIG_MFD_MAX14577 is not set
# CONFIG_MFD_MAX77693 is not set
# CONFIG_MFD_MAX77843 is not set
# CONFIG_MFD_MAX8907 is not set
# CONFIG_MFD_MAX8925 is not set
# CONFIG_MFD_MAX8997 is not set
# CONFIG_MFD_MAX8998 is not set
# CONFIG_MFD_MT6397 is not set
# CONFIG_MFD_MENF21BMC is not set
# CONFIG_MFD_RETU is not set
# CONFIG_MFD_PCF50633 is not set
# CONFIG_MFD_RDC321X is not set
# CONFIG_MFD_RTSX_PCI is not set
# CONFIG_MFD_RT5033 is not set
# CONFIG_MFD_RC5T583 is not set
# CONFIG_MFD_SEC_CORE is not set
# CONFIG_MFD_SI476X_CORE is not set
# CONFIG_MFD_SM501 is not set
# CONFIG_MFD_SKY81452 is not set
# CONFIG_MFD_SMSC is not set
# CONFIG_ABX500_CORE is not set
# CONFIG_MFD_SYSCON is not set
# CONFIG_MFD_TI_AM335X_TSCADC is not set
# CONFIG_MFD_LP3943 is not set
# CONFIG_MFD_LP8788 is not set
# CONFIG_MFD_PALMAS is not set
# CONFIG_TPS6105X is not set
# CONFIG_TPS6507X is not set
# CONFIG_MFD_TPS65086 is not set
# CONFIG_MFD_TPS65090 is not set
# CONFIG_MFD_TPS65217 is not set
# CONFIG_MFD_TPS65218 is not set
# CONFIG_MFD_TPS6586X is not set
# CONFIG_MFD_TPS65912_I2C is not set
# CONFIG_MFD_TPS80031 is not set
# CONFIG_TWL4030_CORE is not set
# CONFIG_TWL6040_CORE is not set
# CONFIG_MFD_WL1273_CORE is not set
# CONFIG_MFD_LM3533 is not set
# CONFIG_MFD_TMIO is not set
# CONFIG_MFD_VX855 is not set
# CONFIG_MFD_ARIZONA_I2C is not set
# CONFIG_MFD_WM8400 is not set
# CONFIG_MFD_WM831X_I2C is not set
# CONFIG_MFD_WM8350_I2C is not set
# CONFIG_MFD_WM8994 is not set
# CONFIG_REGULATOR is not set
# CONFIG_MEDIA_SUPPORT is not set

#
# Graphics support
#
# CONFIG_AGP is not set
CONFIG_VGA_ARB=y
CONFIG_VGA_ARB_MAX_GPUS=16
# CONFIG_VGA_SWITCHEROO is not set
# CONFIG_DRM is not set

#
# ACP (Audio CoProcessor) Configuration
#

#
# Frame buffer Devices
#
CONFIG_FB=y
# CONFIG_FIRMWARE_EDID is not set
CONFIG_FB_CMDLINE=y
CONFIG_FB_NOTIFY=y
# CONFIG_FB_DDC is not set
CONFIG_FB_BOOT_VESA_SUPPORT=y
CONFIG_FB_CFB_FILLRECT=y
CONFIG_FB_CFB_COPYAREA=y
CONFIG_FB_CFB_IMAGEBLIT=y
# CONFIG_FB_CFB_REV_PIXELS_IN_BYTE is not set
# CONFIG_FB_SYS_FILLRECT is not set
# CONFIG_FB_SYS_COPYAREA is not set
# CONFIG_FB_SYS_IMAGEBLIT is not set
# CONFIG_FB_FOREIGN_ENDIAN is not set
# CONFIG_FB_SYS_FOPS is not set
# CONFIG_FB_SVGALIB is not set
# CONFIG_FB_MACMODES is not set
# CONFIG_FB_BACKLIGHT is not set
CONFIG_FB_MODE_HELPERS=y
# CONFIG_FB_TILEBLITTING is not set

#
# Frame buffer hardware drivers
#
# CONFIG_FB_CIRRUS is not set
# CONFIG_FB_PM2 is not set
# CONFIG_FB_CYBER2000 is not set
# CONFIG_FB_ARC is not set
# CONFIG_FB_ASILIANT is not set
# CONFIG_FB_IMSTT is not set
# CONFIG_FB_VGA16 is not set
CONFIG_FB_VESA=y
# CONFIG_FB_N411 is not set
# CONFIG_FB_HGA is not set
# CONFIG_FB_OPENCORES is not set
# CONFIG_FB_S1D13XXX is not set
# CONFIG_FB_NVIDIA is not set
# CONFIG_FB_RIVA is not set
# CONFIG_FB_I740 is not set
# CONFIG_FB_LE80578 is not set
# CONFIG_FB_MATROX is not set
# CONFIG_FB_RADEON is not set
# CONFIG_FB_ATY128 is not set
# CONFIG_FB_ATY is not set
# CONFIG_FB_S3 is not set
# CONFIG_FB_SAVAGE is not set
# CONFIG_FB_SIS is not set
# CONFIG_FB_NEOMAGIC is not set
# CONFIG_FB_KYRO is not set
# CONFIG_FB_3DFX is not set
# CONFIG_FB_VOODOO1 is not set
# CONFIG_FB_VT8623 is not set
# CONFIG_FB_TRIDENT is not set
# CONFIG_FB_ARK is not set
# CONFIG_FB_PM3 is not set
# CONFIG_FB_CARMINE is not set
# CONFIG_FB_IBM_GXT4500 is not set
# CONFIG_FB_VIRTUAL is not set
# CONFIG_FB_METRONOME is not set
# CONFIG_FB_MB862XX is not set
# CONFIG_FB_BROADSHEET is not set
# CONFIG_FB_AUO_K190X is not set
# CONFIG_FB_SIMPLE is not set
# CONFIG_FB_SM712 is not set
# CONFIG_BACKLIGHT_LCD_SUPPORT is not set
# CONFIG_VGASTATE is not set

#
# Console display driver support
#
CONFIG_VGA_CONSOLE=y
CONFIG_VGACON_SOFT_SCROLLBACK=y
CONFIG_VGACON_SOFT_SCROLLBACK_SIZE=64
CONFIG_DUMMY_CONSOLE=y
CONFIG_DUMMY_CONSOLE_COLUMNS=80
CONFIG_DUMMY_CONSOLE_ROWS=25
CONFIG_FRAMEBUFFER_CONSOLE=y
# CONFIG_FRAMEBUFFER_CONSOLE_DETECT_PRIMARY is not set
# CONFIG_FRAMEBUFFER_CONSOLE_ROTATION is not set
# CONFIG_LOGO is not set
# CONFIG_SOUND is not set

#
# HID support
#
CONFIG_HID=y
# CONFIG_HID_BATTERY_STRENGTH is not set
CONFIG_HIDRAW=y
# CONFIG_UHID is not set
CONFIG_HID_GENERIC=y

#
# Special HID drivers
#
# CONFIG_HID_A4TECH is not set
# CONFIG_HID_ACRUX is not set
# CONFIG_HID_APPLE is not set
# CONFIG_HID_AUREAL is not set
# CONFIG_HID_BELKIN is not set
# CONFIG_HID_CHERRY is not set
# CONFIG_HID_CHICONY is not set
# CONFIG_HID_CMEDIA is not set
# CONFIG_HID_CYPRESS is not set
# CONFIG_HID_DRAGONRISE is not set
# CONFIG_HID_EMS_FF is not set
# CONFIG_HID_ELECOM is not set
# CONFIG_HID_EZKEY is not set
# CONFIG_HID_GEMBIRD is not set
# CONFIG_HID_GFRM is not set
# CONFIG_HID_KEYTOUCH is not set
# CONFIG_HID_KYE is not set
# CONFIG_HID_WALTOP is not set
# CONFIG_HID_GYRATION is not set
# CONFIG_HID_ICADE is not set
# CONFIG_HID_TWINHAN is not set
# CONFIG_HID_KENSINGTON is not set
# CONFIG_HID_LCPOWER is not set
# CONFIG_HID_LED is not set
# CONFIG_HID_LENOVO is not set
# CONFIG_HID_LOGITECH is not set
# CONFIG_HID_MAGICMOUSE is not set
# CONFIG_HID_MICROSOFT is not set
# CONFIG_HID_MONTEREY is not set
# CONFIG_HID_MULTITOUCH is not set
# CONFIG_HID_ORTEK is not set
# CONFIG_HID_PANTHERLORD is not set
# CONFIG_HID_PETALYNX is not set
# CONFIG_HID_PICOLCD is not set
# CONFIG_HID_PLANTRONICS is not set
# CONFIG_HID_PRIMAX is not set
# CONFIG_HID_SAITEK is not set
# CONFIG_HID_SAMSUNG is not set
# CONFIG_HID_SPEEDLINK is not set
# CONFIG_HID_STEELSERIES is not set
# CONFIG_HID_SUNPLUS is not set
# CONFIG_HID_RMI is not set
# CONFIG_HID_GREENASIA is not set
# CONFIG_HID_SMARTJOYPLUS is not set
# CONFIG_HID_TIVO is not set
# CONFIG_HID_TOPSEED is not set
# CONFIG_HID_THINGM is not set
# CONFIG_HID_THRUSTMASTER is not set
# CONFIG_HID_WACOM is not set
# CONFIG_HID_WIIMOTE is not set
# CONFIG_HID_XINMO is not set
# CONFIG_HID_ZEROPLUS is not set
# CONFIG_HID_ZYDACRON is not set
# CONFIG_HID_SENSOR_HUB is not set
# CONFIG_HID_ALPS is not set

#
# I2C HID support
#
# CONFIG_I2C_HID is not set
CONFIG_USB_OHCI_LITTLE_ENDIAN=y
# CONFIG_USB_SUPPORT is not set
# CONFIG_UWB is not set
# CONFIG_MMC is not set
# CONFIG_MEMSTICK is not set
CONFIG_NEW_LEDS=y
CONFIG_LEDS_CLASS=y
# CONFIG_LEDS_CLASS_FLASH is not set

#
# LED drivers
#
# CONFIG_LEDS_LM3530 is not set
# CONFIG_LEDS_LM3642 is not set
# CONFIG_LEDS_PCA9532 is not set
# CONFIG_LEDS_LP3944 is not set
# CONFIG_LEDS_LP5521 is not set
# CONFIG_LEDS_LP5523 is not set
# CONFIG_LEDS_LP5562 is not set
# CONFIG_LEDS_LP8501 is not set
# CONFIG_LEDS_LP8860 is not set
# CONFIG_LEDS_CLEVO_MAIL is not set
# CONFIG_LEDS_PCA955X is not set
# CONFIG_LEDS_PCA963X is not set
# CONFIG_LEDS_BD2802 is not set
# CONFIG_LEDS_INTEL_SS4200 is not set
# CONFIG_LEDS_TCA6507 is not set
# CONFIG_LEDS_TLC591XX is not set
# CONFIG_LEDS_LM355x is not set

#
# LED driver for blink(1) USB RGB LED is under Special HID drivers (HID_THINGM)
#
# CONFIG_LEDS_BLINKM is not set

#
# LED Triggers
#
CONFIG_LEDS_TRIGGERS=y
# CONFIG_LEDS_TRIGGER_TIMER is not set
# CONFIG_LEDS_TRIGGER_ONESHOT is not set
# CONFIG_LEDS_TRIGGER_HEARTBEAT is not set
# CONFIG_LEDS_TRIGGER_BACKLIGHT is not set
# CONFIG_LEDS_TRIGGER_CPU is not set
# CONFIG_LEDS_TRIGGER_DEFAULT_ON is not set

#
# iptables trigger is under Netfilter config (LED target)
#
# CONFIG_LEDS_TRIGGER_TRANSIENT is not set
# CONFIG_LEDS_TRIGGER_CAMERA is not set
# CONFIG_LEDS_TRIGGER_PANIC is not set
# CONFIG_ACCESSIBILITY is not set
# CONFIG_INFINIBAND is not set
CONFIG_EDAC_ATOMIC_SCRUB=y
CONFIG_EDAC_SUPPORT=y
# CONFIG_EDAC is not set
CONFIG_RTC_LIB=y
CONFIG_RTC_MC146818_LIB=y
# CONFIG_RTC_CLASS is not set
# CONFIG_DMADEVICES is not set

#
# DMABUF options
#
# CONFIG_SYNC_FILE is not set
# CONFIG_AUXDISPLAY is not set
# CONFIG_UIO is not set
CONFIG_VIRT_DRIVERS=y
CONFIG_VIRTIO=y

#
# Virtio drivers
#
CONFIG_VIRTIO_PCI=y
CONFIG_VIRTIO_PCI_LEGACY=y
# CONFIG_VIRTIO_BALLOON is not set
# CONFIG_VIRTIO_INPUT is not set
# CONFIG_VIRTIO_MMIO is not set

#
# Microsoft Hyper-V guest support
#
# CONFIG_HYPERV is not set
# CONFIG_STAGING is not set
# CONFIG_X86_PLATFORM_DEVICES is not set
# CONFIG_CHROME_PLATFORMS is not set

#
# Hardware Spinlock drivers
#

#
# Clock Source drivers
#
CONFIG_CLKEVT_I8253=y
CONFIG_I8253_LOCK=y
CONFIG_CLKBLD_I8253=y
# CONFIG_ATMEL_PIT is not set
# CONFIG_SH_TIMER_CMT is not set
# CONFIG_SH_TIMER_MTU2 is not set
# CONFIG_SH_TIMER_TMU is not set
# CONFIG_EM_TIMER_STI is not set
# CONFIG_MAILBOX is not set
# CONFIG_IOMMU_SUPPORT is not set

#
# Remoteproc drivers
#
# CONFIG_STE_MODEM_RPROC is not set

#
# Rpmsg drivers
#

#
# SOC (System On Chip) specific Drivers
#

#
# Broadcom SoC drivers
#
# CONFIG_SUNXI_SRAM is not set
# CONFIG_SOC_TI is not set
# CONFIG_PM_DEVFREQ is not set
# CONFIG_EXTCON is not set
# CONFIG_MEMORY is not set
# CONFIG_IIO is not set
# CONFIG_NTB is not set
# CONFIG_VME_BUS is not set
# CONFIG_PWM is not set
CONFIG_ARM_GIC_MAX_NR=1
# CONFIG_IPACK_BUS is not set
# CONFIG_RESET_CONTROLLER is not set
# CONFIG_FMC is not set

#
# PHY Subsystem
#
# CONFIG_GENERIC_PHY is not set
# CONFIG_PHY_PXA_28NM_HSIC is not set
# CONFIG_PHY_PXA_28NM_USB2 is not set
# CONFIG_BCM_KONA_USB2_PHY is not set
# CONFIG_POWERCAP is not set
# CONFIG_MCB is not set

#
# Performance monitor support
#
# CONFIG_RAS is not set
# CONFIG_THUNDERBOLT is not set

#
# Android
#
# CONFIG_ANDROID is not set
# CONFIG_LIBNVDIMM is not set
# CONFIG_NVMEM is not set
# CONFIG_STM is not set
# CONFIG_INTEL_TH is not set

#
# FPGA Configuration Support
#
# CONFIG_FPGA is not set

#
# Firmware Drivers
#
# CONFIG_EDD is not set
CONFIG_FIRMWARE_MEMMAP=y
# CONFIG_DELL_RBU is not set
# CONFIG_DCDBAS is not set
# CONFIG_DMIID is not set
# CONFIG_DMI_SYSFS is not set
CONFIG_DMI_SCAN_MACHINE_NON_EFI_FALLBACK=y
# CONFIG_ISCSI_IBFT_FIND is not set
# CONFIG_FW_CFG_SYSFS is not set
# CONFIG_GOOGLE_FIRMWARE is not set

#
# File systems
#
CONFIG_DCACHE_WORD_ACCESS=y
# CONFIG_EXT2_FS is not set
# CONFIG_EXT3_FS is not set
# CONFIG_EXT4_FS is not set
# CONFIG_REISERFS_FS is not set
# CONFIG_JFS_FS is not set
# CONFIG_XFS_FS is not set
# CONFIG_GFS2_FS is not set
# CONFIG_OCFS2_FS is not set
# CONFIG_BTRFS_FS is not set
# CONFIG_NILFS2_FS is not set
# CONFIG_F2FS_FS is not set
# CONFIG_FS_DAX is not set
CONFIG_FS_POSIX_ACL=y
# CONFIG_EXPORTFS_BLOCK_OPS is not set
CONFIG_FILE_LOCKING=y
CONFIG_MANDATORY_FILE_LOCKING=y
# CONFIG_FS_ENCRYPTION is not set
# CONFIG_FSNOTIFY is not set
# CONFIG_DNOTIFY is not set
# CONFIG_INOTIFY_USER is not set
# CONFIG_FANOTIFY is not set
# CONFIG_QUOTA is not set
# CONFIG_QUOTACTL is not set
# CONFIG_AUTOFS4_FS is not set
# CONFIG_FUSE_FS is not set
# CONFIG_OVERLAY_FS is not set

#
# Caches
#
# CONFIG_FSCACHE is not set

#
# CD-ROM/DVD Filesystems
#
# CONFIG_ISO9660_FS is not set
# CONFIG_UDF_FS is not set

#
# DOS/FAT/NT Filesystems
#
# CONFIG_MSDOS_FS is not set
# CONFIG_VFAT_FS is not set
# CONFIG_NTFS_FS is not set

#
# Pseudo filesystems
#
CONFIG_PROC_FS=y
CONFIG_PROC_KCORE=y
CONFIG_PROC_SYSCTL=y
CONFIG_PROC_PAGE_MONITOR=y
# CONFIG_PROC_CHILDREN is not set
CONFIG_KERNFS=y
CONFIG_SYSFS=y
CONFIG_TMPFS=y
CONFIG_TMPFS_POSIX_ACL=y
CONFIG_TMPFS_XATTR=y
# CONFIG_HUGETLBFS is not set
# CONFIG_HUGETLB_PAGE is not set
CONFIG_CONFIGFS_FS=y
# CONFIG_MISC_FILESYSTEMS is not set
CONFIG_NETWORK_FILESYSTEMS=y
# CONFIG_NFS_FS is not set
# CONFIG_NFSD is not set
# CONFIG_CEPH_FS is not set
# CONFIG_CIFS is not set
# CONFIG_NCP_FS is not set
# CONFIG_CODA_FS is not set
# CONFIG_AFS_FS is not set
CONFIG_9P_FS=y
CONFIG_9P_FS_POSIX_ACL=y
# CONFIG_9P_FS_SECURITY is not set
CONFIG_NLS=y
CONFIG_NLS_DEFAULT="iso8859-1"
# CONFIG_NLS_CODEPAGE_437 is not set
# CONFIG_NLS_CODEPAGE_737 is not set
# CONFIG_NLS_CODEPAGE_775 is not set
# CONFIG_NLS_CODEPAGE_850 is not set
# CONFIG_NLS_CODEPAGE_852 is not set
# CONFIG_NLS_CODEPAGE_855 is not set
# CONFIG_NLS_CODEPAGE_857 is not set
# CONFIG_NLS_CODEPAGE_860 is not set
# CONFIG_NLS_CODEPAGE_861 is not set
# CONFIG_NLS_CODEPAGE_862 is not set
# CONFIG_NLS_CODEPAGE_863 is not set
# CONFIG_NLS_CODEPAGE_864 is not set
# CONFIG_NLS_CODEPAGE_865 is not set
# CONFIG_NLS_CODEPAGE_866 is not set
# CONFIG_NLS_CODEPAGE_869 is not set
# CONFIG_NLS_CODEPAGE_936 is not set
# CONFIG_NLS_CODEPAGE_950 is not set
# CONFIG_NLS_CODEPAGE_932 is not set
# CONFIG_NLS_CODEPAGE_949 is not set
# CONFIG_NLS_CODEPAGE_874 is not set
# CONFIG_NLS_ISO8859_8 is not set
# CONFIG_NLS_CODEPAGE_1250 is not set
# CONFIG_NLS_CODEPAGE_1251 is not set
# CONFIG_NLS_ASCII is not set
# CONFIG_NLS_ISO8859_1 is not set
# CONFIG_NLS_ISO8859_2 is not set
# CONFIG_NLS_ISO8859_3 is not set
# CONFIG_NLS_ISO8859_4 is not set
# CONFIG_NLS_ISO8859_5 is not set
# CONFIG_NLS_ISO8859_6 is not set
# CONFIG_NLS_ISO8859_7 is not set
# CONFIG_NLS_ISO8859_9 is not set
# CONFIG_NLS_ISO8859_13 is not set
# CONFIG_NLS_ISO8859_14 is not set
# CONFIG_NLS_ISO8859_15 is not set
# CONFIG_NLS_KOI8_R is not set
# CONFIG_NLS_KOI8_U is not set
# CONFIG_NLS_MAC_ROMAN is not set
# CONFIG_NLS_MAC_CELTIC is not set
# CONFIG_NLS_MAC_CENTEURO is not set
# CONFIG_NLS_MAC_CROATIAN is not set
# CONFIG_NLS_MAC_CYRILLIC is not set
# CONFIG_NLS_MAC_GAELIC is not set
# CONFIG_NLS_MAC_GREEK is not set
# CONFIG_NLS_MAC_ICELAND is not set
# CONFIG_NLS_MAC_INUIT is not set
# CONFIG_NLS_MAC_ROMANIAN is not set
# CONFIG_NLS_MAC_TURKISH is not set
# CONFIG_NLS_UTF8 is not set
# CONFIG_DLM is not set

#
# Kernel hacking
#
CONFIG_TRACE_IRQFLAGS_SUPPORT=y

#
# printk and dmesg options
#
CONFIG_PRINTK_TIME=y
CONFIG_MESSAGE_LOGLEVEL_DEFAULT=4
# CONFIG_BOOT_PRINTK_DELAY is not set
# CONFIG_DYNAMIC_DEBUG is not set

#
# Compile-time checks and compiler options
#
CONFIG_DEBUG_INFO=y
# CONFIG_DEBUG_INFO_REDUCED is not set
# CONFIG_DEBUG_INFO_SPLIT is not set
# CONFIG_DEBUG_INFO_DWARF4 is not set
# CONFIG_GDB_SCRIPTS is not set
CONFIG_ENABLE_WARN_DEPRECATED=y
CONFIG_ENABLE_MUST_CHECK=y
CONFIG_FRAME_WARN=1024
# CONFIG_STRIP_ASM_SYMS is not set
# CONFIG_READABLE_ASM is not set
# CONFIG_UNUSED_SYMBOLS is not set
# CONFIG_PAGE_OWNER is not set
CONFIG_DEBUG_FS=y
# CONFIG_HEADERS_CHECK is not set
CONFIG_DEBUG_SECTION_MISMATCH=y
CONFIG_SECTION_MISMATCH_WARN_ONLY=y
CONFIG_ARCH_WANT_FRAME_POINTERS=y
CONFIG_FRAME_POINTER=y
# CONFIG_STACK_VALIDATION is not set
# CONFIG_DEBUG_FORCE_WEAK_PER_CPU is not set
CONFIG_MAGIC_SYSRQ=y
CONFIG_MAGIC_SYSRQ_DEFAULT_ENABLE=0x1
CONFIG_DEBUG_KERNEL=y

#
# Memory Debugging
#
CONFIG_PAGE_EXTENSION=y
CONFIG_DEBUG_PAGEALLOC=y
# CONFIG_DEBUG_PAGEALLOC_ENABLE_DEFAULT is not set
# CONFIG_PAGE_POISONING is not set
# CONFIG_DEBUG_PAGE_REF is not set
CONFIG_DEBUG_OBJECTS=y
# CONFIG_DEBUG_OBJECTS_SELFTEST is not set
CONFIG_DEBUG_OBJECTS_FREE=y
CONFIG_DEBUG_OBJECTS_TIMERS=y
CONFIG_DEBUG_OBJECTS_WORK=y
CONFIG_DEBUG_OBJECTS_RCU_HEAD=y
CONFIG_DEBUG_OBJECTS_PERCPU_COUNTER=y
CONFIG_DEBUG_OBJECTS_ENABLE_DEFAULT=1
CONFIG_SLUB_DEBUG_ON=y
# CONFIG_SLUB_STATS is not set
CONFIG_HAVE_DEBUG_KMEMLEAK=y
CONFIG_DEBUG_KMEMLEAK=y
CONFIG_DEBUG_KMEMLEAK_EARLY_LOG_SIZE=400
# CONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF is not set
CONFIG_DEBUG_STACK_USAGE=y
# CONFIG_DEBUG_VM is not set
# CONFIG_DEBUG_VIRTUAL is not set
# CONFIG_DEBUG_MEMORY_INIT is not set
# CONFIG_DEBUG_PER_CPU_MAPS is not set
CONFIG_HAVE_DEBUG_STACKOVERFLOW=y
# CONFIG_DEBUG_STACKOVERFLOW is not set
CONFIG_HAVE_ARCH_KMEMCHECK=y
CONFIG_HAVE_ARCH_KASAN=y
# CONFIG_KASAN is not set
CONFIG_ARCH_HAS_KCOV=y
# CONFIG_KCOV is not set
# CONFIG_DEBUG_SHIRQ is not set

#
# Debug Lockups and Hangs
#
CONFIG_LOCKUP_DETECTOR=y
CONFIG_HARDLOCKUP_DETECTOR=y
# CONFIG_BOOTPARAM_HARDLOCKUP_PANIC is not set
CONFIG_BOOTPARAM_HARDLOCKUP_PANIC_VALUE=0
# CONFIG_BOOTPARAM_SOFTLOCKUP_PANIC is not set
CONFIG_BOOTPARAM_SOFTLOCKUP_PANIC_VALUE=0
CONFIG_DETECT_HUNG_TASK=y
CONFIG_DEFAULT_HUNG_TASK_TIMEOUT=120
# CONFIG_BOOTPARAM_HUNG_TASK_PANIC is not set
CONFIG_BOOTPARAM_HUNG_TASK_PANIC_VALUE=0
# CONFIG_WQ_WATCHDOG is not set
CONFIG_PANIC_ON_OOPS=y
CONFIG_PANIC_ON_OOPS_VALUE=1
CONFIG_PANIC_TIMEOUT=0
CONFIG_SCHED_DEBUG=y
CONFIG_SCHED_INFO=y
CONFIG_SCHEDSTATS=y
# CONFIG_SCHED_STACK_END_CHECK is not set
# CONFIG_DEBUG_TIMEKEEPING is not set
CONFIG_TIMER_STATS=y
CONFIG_DEBUG_PREEMPT=y

#
# Lock Debugging (spinlocks, mutexes, etc...)
#
CONFIG_DEBUG_RT_MUTEXES=y
CONFIG_DEBUG_SPINLOCK=y
CONFIG_DEBUG_MUTEXES=y
# CONFIG_DEBUG_WW_MUTEX_SLOWPATH is not set
CONFIG_DEBUG_LOCK_ALLOC=y
CONFIG_PROVE_LOCKING=y
CONFIG_LOCKDEP=y
CONFIG_LOCK_STAT=y
CONFIG_DEBUG_LOCKDEP=y
CONFIG_DEBUG_ATOMIC_SLEEP=y
# CONFIG_DEBUG_LOCKING_API_SELFTESTS is not set
# CONFIG_LOCK_TORTURE_TEST is not set
CONFIG_TRACE_IRQFLAGS=y
CONFIG_STACKTRACE=y
# CONFIG_DEBUG_KOBJECT is not set
# CONFIG_DEBUG_KOBJECT_RELEASE is not set
CONFIG_DEBUG_BUGVERBOSE=y
CONFIG_DEBUG_LIST=y
CONFIG_DEBUG_PI_LIST=y
# CONFIG_DEBUG_SG is not set
CONFIG_DEBUG_NOTIFIERS=y
# CONFIG_DEBUG_CREDENTIALS is not set

#
# RCU Debugging
#
CONFIG_PROVE_RCU=y
CONFIG_PROVE_RCU_REPEATEDLY=y
CONFIG_SPARSE_RCU_POINTER=y
# CONFIG_TORTURE_TEST is not set
# CONFIG_RCU_PERF_TEST is not set
# CONFIG_RCU_TORTURE_TEST is not set
CONFIG_RCU_CPU_STALL_TIMEOUT=60
# CONFIG_RCU_TRACE is not set
# CONFIG_RCU_EQS_DEBUG is not set
# CONFIG_DEBUG_WQ_FORCE_RR_CPU is not set
# CONFIG_DEBUG_BLOCK_EXT_DEVT is not set
# CONFIG_NOTIFIER_ERROR_INJECTION is not set
# CONFIG_FAULT_INJECTION is not set
CONFIG_LATENCYTOP=y
CONFIG_ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS=y
CONFIG_DEBUG_STRICT_USER_COPY_CHECKS=y
CONFIG_USER_STACKTRACE_SUPPORT=y
CONFIG_NOP_TRACER=y
CONFIG_HAVE_FUNCTION_TRACER=y
CONFIG_HAVE_FUNCTION_GRAPH_TRACER=y
CONFIG_HAVE_FUNCTION_GRAPH_FP_TEST=y
CONFIG_HAVE_DYNAMIC_FTRACE=y
CONFIG_HAVE_DYNAMIC_FTRACE_WITH_REGS=y
CONFIG_HAVE_FTRACE_MCOUNT_RECORD=y
CONFIG_HAVE_SYSCALL_TRACEPOINTS=y
CONFIG_HAVE_FENTRY=y
CONFIG_HAVE_C_RECORDMCOUNT=y
CONFIG_TRACE_CLOCK=y
CONFIG_RING_BUFFER=y
CONFIG_EVENT_TRACING=y
CONFIG_CONTEXT_SWITCH_TRACER=y
CONFIG_TRACING=y
CONFIG_GENERIC_TRACER=y
CONFIG_TRACING_SUPPORT=y
CONFIG_FTRACE=y
CONFIG_FUNCTION_TRACER=y
CONFIG_FUNCTION_GRAPH_TRACER=y
# CONFIG_IRQSOFF_TRACER is not set
# CONFIG_PREEMPT_TRACER is not set
# CONFIG_SCHED_TRACER is not set
# CONFIG_FTRACE_SYSCALLS is not set
# CONFIG_TRACER_SNAPSHOT is not set
CONFIG_BRANCH_PROFILE_NONE=y
# CONFIG_PROFILE_ANNOTATED_BRANCHES is not set
# CONFIG_PROFILE_ALL_BRANCHES is not set
# CONFIG_STACK_TRACER is not set
# CONFIG_BLK_DEV_IO_TRACE is not set
# CONFIG_UPROBE_EVENT is not set
# CONFIG_PROBE_EVENTS is not set
CONFIG_DYNAMIC_FTRACE=y
CONFIG_DYNAMIC_FTRACE_WITH_REGS=y
# CONFIG_FUNCTION_PROFILER is not set
CONFIG_FTRACE_MCOUNT_RECORD=y
# CONFIG_FTRACE_STARTUP_TEST is not set
# CONFIG_MMIOTRACE is not set
# CONFIG_HIST_TRIGGERS is not set
# CONFIG_TRACEPOINT_BENCHMARK is not set
# CONFIG_RING_BUFFER_BENCHMARK is not set
# CONFIG_RING_BUFFER_STARTUP_TEST is not set
# CONFIG_TRACE_ENUM_MAP_FILE is not set

#
# Runtime Testing
#
# CONFIG_LKDTM is not set
# CONFIG_TEST_LIST_SORT is not set
# CONFIG_BACKTRACE_SELF_TEST is not set
# CONFIG_RBTREE_TEST is not set
# CONFIG_ATOMIC64_SELFTEST is not set
# CONFIG_TEST_HEXDUMP is not set
# CONFIG_TEST_STRING_HELPERS is not set
# CONFIG_TEST_KSTRTOX is not set
# CONFIG_TEST_PRINTF is not set
# CONFIG_TEST_BITMAP is not set
# CONFIG_TEST_UUID is not set
# CONFIG_TEST_RHASHTABLE is not set
# CONFIG_TEST_HASH is not set
# CONFIG_PROVIDE_OHCI1394_DMA_INIT is not set
# CONFIG_DMA_API_DEBUG is not set
# CONFIG_TEST_FIRMWARE is not set
# CONFIG_TEST_UDELAY is not set
# CONFIG_MEMTEST is not set
# CONFIG_SAMPLES is not set
CONFIG_HAVE_ARCH_KGDB=y
# CONFIG_KGDB is not set
CONFIG_ARCH_HAS_UBSAN_SANITIZE_ALL=y
# CONFIG_UBSAN is not set
CONFIG_ARCH_HAS_DEVMEM_IS_ALLOWED=y
# CONFIG_STRICT_DEVMEM is not set
# CONFIG_X86_VERBOSE_BOOTUP is not set
CONFIG_EARLY_PRINTK=y
# CONFIG_EARLY_PRINTK_DBGP is not set
CONFIG_X86_PTDUMP_CORE=y
# CONFIG_X86_PTDUMP is not set
CONFIG_DEBUG_RODATA_TEST=y
CONFIG_DEBUG_WX=y
CONFIG_DOUBLEFAULT=y
# CONFIG_DEBUG_TLBFLUSH is not set
# CONFIG_IOMMU_DEBUG is not set
# CONFIG_IOMMU_STRESS is not set
CONFIG_HAVE_MMIOTRACE_SUPPORT=y
CONFIG_IO_DELAY_TYPE_0X80=0
CONFIG_IO_DELAY_TYPE_0XED=1
CONFIG_IO_DELAY_TYPE_UDELAY=2
CONFIG_IO_DELAY_TYPE_NONE=3
CONFIG_IO_DELAY_0X80=y
# CONFIG_IO_DELAY_0XED is not set
# CONFIG_IO_DELAY_UDELAY is not set
# CONFIG_IO_DELAY_NONE is not set
CONFIG_DEFAULT_IO_DELAY_TYPE=0
# CONFIG_DEBUG_BOOT_PARAMS is not set
# CONFIG_CPA_DEBUG is not set
# CONFIG_OPTIMIZE_INLINING is not set
# CONFIG_DEBUG_ENTRY is not set
# CONFIG_DEBUG_NMI_SELFTEST is not set
CONFIG_X86_DEBUG_FPU=y
# CONFIG_PUNIT_ATOM_DEBUG is not set

#
# Security options
#
# CONFIG_KEYS is not set
# CONFIG_SECURITY_DMESG_RESTRICT is not set
# CONFIG_SECURITY is not set
# CONFIG_SECURITYFS is not set
CONFIG_HAVE_HARDENED_USERCOPY_ALLOCATOR=y
CONFIG_HAVE_ARCH_HARDENED_USERCOPY=y
# CONFIG_HARDENED_USERCOPY is not set
CONFIG_DEFAULT_SECURITY_DAC=y
CONFIG_DEFAULT_SECURITY=""
CONFIG_CRYPTO=y

#
# Crypto core or helper
#
CONFIG_CRYPTO_ALGAPI=y
CONFIG_CRYPTO_ALGAPI2=y
CONFIG_CRYPTO_AEAD=y
CONFIG_CRYPTO_AEAD2=y
CONFIG_CRYPTO_BLKCIPHER=y
CONFIG_CRYPTO_BLKCIPHER2=y
CONFIG_CRYPTO_HASH=y
CONFIG_CRYPTO_HASH2=y
CONFIG_CRYPTO_RNG=y
CONFIG_CRYPTO_RNG2=y
CONFIG_CRYPTO_RNG_DEFAULT=y
CONFIG_CRYPTO_AKCIPHER2=y
CONFIG_CRYPTO_KPP2=y
# CONFIG_CRYPTO_RSA is not set
# CONFIG_CRYPTO_DH is not set
# CONFIG_CRYPTO_ECDH is not set
CONFIG_CRYPTO_MANAGER=y
CONFIG_CRYPTO_MANAGER2=y
# CONFIG_CRYPTO_USER is not set
CONFIG_CRYPTO_MANAGER_DISABLE_TESTS=y
CONFIG_CRYPTO_GF128MUL=y
CONFIG_CRYPTO_NULL=y
CONFIG_CRYPTO_NULL2=y
# CONFIG_CRYPTO_PCRYPT is not set
CONFIG_CRYPTO_WORKQUEUE=y
# CONFIG_CRYPTO_CRYPTD is not set
# CONFIG_CRYPTO_MCRYPTD is not set
# CONFIG_CRYPTO_AUTHENC is not set

#
# Authenticated Encryption with Associated Data
#
CONFIG_CRYPTO_CCM=y
CONFIG_CRYPTO_GCM=y
# CONFIG_CRYPTO_CHACHA20POLY1305 is not set
CONFIG_CRYPTO_SEQIV=y
CONFIG_CRYPTO_ECHAINIV=y

#
# Block modes
#
# CONFIG_CRYPTO_CBC is not set
CONFIG_CRYPTO_CTR=y
# CONFIG_CRYPTO_CTS is not set
CONFIG_CRYPTO_ECB=y
# CONFIG_CRYPTO_LRW is not set
# CONFIG_CRYPTO_PCBC is not set
# CONFIG_CRYPTO_XTS is not set
# CONFIG_CRYPTO_KEYWRAP is not set

#
# Hash modes
#
# CONFIG_CRYPTO_CMAC is not set
CONFIG_CRYPTO_HMAC=y
# CONFIG_CRYPTO_XCBC is not set
# CONFIG_CRYPTO_VMAC is not set

#
# Digest
#
CONFIG_CRYPTO_CRC32C=y
# CONFIG_CRYPTO_CRC32C_INTEL is not set
# CONFIG_CRYPTO_CRC32 is not set
# CONFIG_CRYPTO_CRC32_PCLMUL is not set
CONFIG_CRYPTO_CRCT10DIF=y
CONFIG_CRYPTO_GHASH=y
# CONFIG_CRYPTO_POLY1305 is not set
# CONFIG_CRYPTO_POLY1305_X86_64 is not set
# CONFIG_CRYPTO_MD4 is not set
# CONFIG_CRYPTO_MD5 is not set
CONFIG_CRYPTO_MICHAEL_MIC=y
# CONFIG_CRYPTO_RMD128 is not set
# CONFIG_CRYPTO_RMD160 is not set
# CONFIG_CRYPTO_RMD256 is not set
# CONFIG_CRYPTO_RMD320 is not set
# CONFIG_CRYPTO_SHA1 is not set
# CONFIG_CRYPTO_SHA1_SSSE3 is not set
# CONFIG_CRYPTO_SHA256_SSSE3 is not set
# CONFIG_CRYPTO_SHA512_SSSE3 is not set
# CONFIG_CRYPTO_SHA1_MB is not set
# CONFIG_CRYPTO_SHA256_MB is not set
# CONFIG_CRYPTO_SHA512_MB is not set
CONFIG_CRYPTO_SHA256=y
# CONFIG_CRYPTO_SHA512 is not set
# CONFIG_CRYPTO_SHA3 is not set
# CONFIG_CRYPTO_TGR192 is not set
# CONFIG_CRYPTO_WP512 is not set
# CONFIG_CRYPTO_GHASH_CLMUL_NI_INTEL is not set

#
# Ciphers
#
CONFIG_CRYPTO_AES=y
# CONFIG_CRYPTO_AES_X86_64 is not set
# CONFIG_CRYPTO_AES_NI_INTEL is not set
# CONFIG_CRYPTO_ANUBIS is not set
CONFIG_CRYPTO_ARC4=y
# CONFIG_CRYPTO_BLOWFISH is not set
# CONFIG_CRYPTO_BLOWFISH_X86_64 is not set
# CONFIG_CRYPTO_CAMELLIA is not set
# CONFIG_CRYPTO_CAMELLIA_X86_64 is not set
# CONFIG_CRYPTO_CAMELLIA_AESNI_AVX_X86_64 is not set
# CONFIG_CRYPTO_CAMELLIA_AESNI_AVX2_X86_64 is not set
# CONFIG_CRYPTO_CAST5 is not set
# CONFIG_CRYPTO_CAST5_AVX_X86_64 is not set
# CONFIG_CRYPTO_CAST6 is not set
# CONFIG_CRYPTO_CAST6_AVX_X86_64 is not set
# CONFIG_CRYPTO_DES is not set
# CONFIG_CRYPTO_DES3_EDE_X86_64 is not set
# CONFIG_CRYPTO_FCRYPT is not set
# CONFIG_CRYPTO_KHAZAD is not set
# CONFIG_CRYPTO_SALSA20 is not set
# CONFIG_CRYPTO_SALSA20_X86_64 is not set
# CONFIG_CRYPTO_CHACHA20 is not set
# CONFIG_CRYPTO_CHACHA20_X86_64 is not set
# CONFIG_CRYPTO_SEED is not set
# CONFIG_CRYPTO_SERPENT is not set
# CONFIG_CRYPTO_SERPENT_SSE2_X86_64 is not set
# CONFIG_CRYPTO_SERPENT_AVX_X86_64 is not set
# CONFIG_CRYPTO_SERPENT_AVX2_X86_64 is not set
# CONFIG_CRYPTO_TEA is not set
# CONFIG_CRYPTO_TWOFISH is not set
# CONFIG_CRYPTO_TWOFISH_X86_64 is not set
# CONFIG_CRYPTO_TWOFISH_X86_64_3WAY is not set
# CONFIG_CRYPTO_TWOFISH_AVX_X86_64 is not set

#
# Compression
#
# CONFIG_CRYPTO_DEFLATE is not set
# CONFIG_CRYPTO_LZO is not set
# CONFIG_CRYPTO_842 is not set
# CONFIG_CRYPTO_LZ4 is not set
# CONFIG_CRYPTO_LZ4HC is not set

#
# Random Number Generation
#
# CONFIG_CRYPTO_ANSI_CPRNG is not set
CONFIG_CRYPTO_DRBG_MENU=y
CONFIG_CRYPTO_DRBG_HMAC=y
# CONFIG_CRYPTO_DRBG_HASH is not set
# CONFIG_CRYPTO_DRBG_CTR is not set
CONFIG_CRYPTO_DRBG=y
CONFIG_CRYPTO_JITTERENTROPY=y
# CONFIG_CRYPTO_USER_API_HASH is not set
# CONFIG_CRYPTO_USER_API_SKCIPHER is not set
# CONFIG_CRYPTO_USER_API_RNG is not set
# CONFIG_CRYPTO_USER_API_AEAD is not set
# CONFIG_CRYPTO_HW is not set

#
# Certificates for signature checking
#
CONFIG_HAVE_KVM=y
# CONFIG_VIRTUALIZATION is not set
CONFIG_BINARY_PRINTF=y

#
# Library routines
#
CONFIG_BITREVERSE=y
# CONFIG_HAVE_ARCH_BITREVERSE is not set
CONFIG_RATIONAL=y
CONFIG_GENERIC_STRNCPY_FROM_USER=y
CONFIG_GENERIC_STRNLEN_USER=y
CONFIG_GENERIC_NET_UTILS=y
CONFIG_GENERIC_FIND_FIRST_BIT=y
CONFIG_GENERIC_PCI_IOMAP=y
CONFIG_GENERIC_IOMAP=y
CONFIG_GENERIC_IO=y
CONFIG_ARCH_USE_CMPXCHG_LOCKREF=y
CONFIG_ARCH_HAS_FAST_MULTIPLIER=y
CONFIG_CRC_CCITT=y
CONFIG_CRC16=y
# CONFIG_CRC_T10DIF is not set
CONFIG_CRC_ITU_T=y
CONFIG_CRC32=y
# CONFIG_CRC32_SELFTEST is not set
CONFIG_CRC32_SLICEBY8=y
# CONFIG_CRC32_SLICEBY4 is not set
# CONFIG_CRC32_SARWATE is not set
# CONFIG_CRC32_BIT is not set
# CONFIG_CRC7 is not set
CONFIG_LIBCRC32C=y
# CONFIG_CRC8 is not set
# CONFIG_AUDIT_ARCH_COMPAT_GENERIC is not set
# CONFIG_RANDOM32_SELFTEST is not set
# CONFIG_XZ_DEC is not set
# CONFIG_XZ_DEC_BCJ is not set
CONFIG_HAS_IOMEM=y
CONFIG_HAS_IOPORT_MAP=y
CONFIG_HAS_DMA=y
CONFIG_CPU_RMAP=y
CONFIG_DQL=y
CONFIG_NLATTR=y
CONFIG_ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE=y
# CONFIG_CORDIC is not set
# CONFIG_DDR is not set
# CONFIG_IRQ_POLL is not set
CONFIG_FONT_SUPPORT=y
# CONFIG_FONTS is not set
CONFIG_FONT_8x8=y
CONFIG_FONT_8x16=y
# CONFIG_SG_SPLIT is not set
# CONFIG_SG_POOL is not set
CONFIG_ARCH_HAS_SG_CHAIN=y
CONFIG_ARCH_HAS_PMEM_API=y
CONFIG_ARCH_HAS_MMIO_FLUSH=y

Re: [v2 PATCH 0/2] rhashtable: rhashtable with duplicate objects

[Johannes Berg]

On Mon, 2016-09-19 at 11:27 +0200, Johannes Berg wrote:
> > 
> I have a feeling there's a bug with ht->nelems, since the crash is
> always in the grow worker, but I haven't quite put my finger on it
> yet.
> 
Btw, I should not actually get into the duplicate case here.

johannes

Re: [v2 PATCH 0/2] rhashtable: rhashtable with duplicate objects

[Herbert Xu]

On Mon, Sep 19, 2016 at 11:27:24AM +0200, Johannes Berg wrote:
> 
> I have a feeling there's a bug with ht->nelems, since the crash is
> always in the grow worker, but I haven't quite put my finger on it yet.

Can you show me a stack trace?

Thanks,
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

Re: [v2 PATCH 0/2] rhashtable: rhashtable with duplicate objects

[Herbert Xu]

On Mon, Sep 19, 2016 at 11:27:24AM +0200, Johannes Berg wrote:
> 
> I have a feeling there's a bug with ht->nelems, since the crash is
> always in the grow worker, but I haven't quite put my finger on it yet.

Can you show me a stack trace?

Thanks,
-- 
Email: Herbert Xu <herbert-lOAM2aK0SrRLBo1qDEOMRrpzq4S04n8Q@public.gmane.org>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

Re: [v2 PATCH 0/2] rhashtable: rhashtable with duplicate objects

[Johannes Berg]

On Mon, 2016-09-19 at 17:34 +0800, Herbert Xu wrote:
> On Mon, Sep 19, 2016 at 11:27:24AM +0200, Johannes Berg wrote:
> > 
> > 
> > I have a feeling there's a bug with ht->nelems, since the crash is
> > always in the grow worker, but I haven't quite put my finger on it
> > yet.
> 
> Can you show me a stack trace?

Oops, just deleted the old ones to reproduce with some debug printks :)

It's always while trying to grow a table from the worker; it kills
processes, but eventually no process are left and the kernel panics.

I'll send you a trace when I have one again - I'm running a new
reproduction now.

johannes

Re: [v2 PATCH 0/2] rhashtable: rhashtable with duplicate objects

[Johannes Berg]

On Mon, 2016-09-19 at 17:34 +0800, Herbert Xu wrote:
> On Mon, Sep 19, 2016 at 11:27:24AM +0200, Johannes Berg wrote:
> > 
> > 
> > I have a feeling there's a bug with ht->nelems, since the crash is
> > always in the grow worker, but I haven't quite put my finger on it
> > yet.
> 
> Can you show me a stack trace?

Oops, just deleted the old ones to reproduce with some debug printks :)

It's always while trying to grow a table from the worker; it kills
processes, but eventually no process are left and the kernel panics.

I'll send you a trace when I have one again - I'm running a new
reproduction now.

johannes

Re: [v2 PATCH 0/2] rhashtable: rhashtable with duplicate objects

[Johannes Berg]

On Mon, 2016-09-19 at 17:34 +0800, Herbert Xu wrote:
> On Mon, Sep 19, 2016 at 11:27:24AM +0200, Johannes Berg wrote:
> > 
> > 
> > I have a feeling there's a bug with ht->nelems, since the crash is
> > always in the grow worker, but I haven't quite put my finger on it
> > yet.
> 
> Can you show me a stack trace?
> 
The stack trace is useless, but my other annotation showed that the
table's nelems *underflowed* to -1, so now the worker will continue to
try to grow it forever.

johannes

Re: [v2 PATCH 0/2] rhashtable: rhashtable with duplicate objects

[Johannes Berg]

> The stack trace is useless, but my other annotation showed that the
> table's nelems *underflowed* to -1, so now the worker will continue
> to try to grow it forever.
> 

And this *was* actually a case of duplication, afaict, since it was
multiple virtual interfaces on the same device all connecting to the
same AP.

johannes

Re: [v2 PATCH 0/2] rhashtable: rhashtable with duplicate objects

[Johannes Berg]

> The stack trace is useless, but my other annotation showed that the
> table's nelems *underflowed* to -1, so now the worker will continue
> to try to grow it forever.
> 

And this *was* actually a case of duplication, afaict, since it was
multiple virtual interfaces on the same device all connecting to the
same AP.

johannes

Re: [v2 PATCH 0/2] rhashtable: rhashtable with duplicate objects

[Johannes Berg]

On Mon, 2016-09-19 at 11:54 +0200, Johannes Berg wrote:
> > 
> > The stack trace is useless, but my other annotation showed that the
> > table's nelems *underflowed* to -1, so now the worker will continue
> > to try to grow it forever.
> > 
> 
> And this *was* actually a case of duplication, afaict, since it was
> multiple virtual interfaces on the same device all connecting to the
> same AP.

It seems that __rhashtable_remove_fast_one() should return 0 even in
the case of err==1 for the "skip all the maintenance due to list
deletion"?

--- a/include/linux/rhashtable.h
+++ b/include/linux/rhashtable.h
@@ -1009,7 +1009,7 @@ static inline int __rhashtable_remove_fast_one(
                err = 0;
        }
 
-       return err;
+       return err < 0 ? err : 0;
 }

But that in itself doesn't help.

johannes

Re: [v2 PATCH 0/2] rhashtable: rhashtable with duplicate objects

[Johannes Berg]

On Mon, 2016-09-19 at 11:54 +0200, Johannes Berg wrote:
> > 
> > The stack trace is useless, but my other annotation showed that the
> > table's nelems *underflowed* to -1, so now the worker will continue
> > to try to grow it forever.
> > 
> 
> And this *was* actually a case of duplication, afaict, since it was
> multiple virtual interfaces on the same device all connecting to the
> same AP.

It seems that __rhashtable_remove_fast_one() should return 0 even in
the case of err==1 for the "skip all the maintenance due to list
deletion"?

--- a/include/linux/rhashtable.h
+++ b/include/linux/rhashtable.h
@@ -1009,7 +1009,7 @@ static inline int __rhashtable_remove_fast_one(
                err = 0;
        }
 
-       return err;
+       return err < 0 ? err : 0;
 }

But that in itself doesn't help.

johannes

Re: [v2 PATCH 0/2] rhashtable: rhashtable with duplicate objects

[Johannes Berg]

On Mon, 2016-09-19 at 12:02 +0200, Johannes Berg wrote:
> On Mon, 2016-09-19 at 11:54 +0200, Johannes Berg wrote:
> > 
> > > 
> > > 
> > > The stack trace is useless, but my other annotation showed that
> > > the
> > > table's nelems *underflowed* to -1, so now the worker will
> > > continue
> > > to try to grow it forever.
> > > 
> > 
> > And this *was* actually a case of duplication, afaict, since it was
> > multiple virtual interfaces on the same device all connecting to
> > the
> > same AP.
> 
> It seems that __rhashtable_remove_fast_one() should return 0 even in
> the case of err==1 for the "skip all the maintenance due to list
> deletion"?
> 
> --- a/include/linux/rhashtable.h
> +++ b/include/linux/rhashtable.h
> @@ -1009,7 +1009,7 @@ static inline int __rhashtable_remove_fast_one(
>                 err = 0;
>         }
>  
> -       return err;
> +       return err < 0 ? err : 0;
>  }
> 

No, that's obviously bogus and already handled - wrong case anyway.
Sorry.

johannes

Re: [v2 PATCH 0/2] rhashtable: rhashtable with duplicate objects

[Johannes Berg]

On Mon, 2016-09-19 at 12:02 +0200, Johannes Berg wrote:
> On Mon, 2016-09-19 at 11:54 +0200, Johannes Berg wrote:
> > 
> > > 
> > > 
> > > The stack trace is useless, but my other annotation showed that
> > > the
> > > table's nelems *underflowed* to -1, so now the worker will
> > > continue
> > > to try to grow it forever.
> > > 
> > 
> > And this *was* actually a case of duplication, afaict, since it was
> > multiple virtual interfaces on the same device all connecting to
> > the
> > same AP.
> 
> It seems that __rhashtable_remove_fast_one() should return 0 even in
> the case of err==1 for the "skip all the maintenance due to list
> deletion"?
> 
> --- a/include/linux/rhashtable.h
> +++ b/include/linux/rhashtable.h
> @@ -1009,7 +1009,7 @@ static inline int __rhashtable_remove_fast_one(
>                 err = 0;
>         }
>  
> -       return err;
> +       return err < 0 ? err : 0;
>  }
> 

No, that's obviously bogus and already handled - wrong case anyway.
Sorry.

johannes

Re: [v2 PATCH 0/2] rhashtable: rhashtable with duplicate objects

[Johannes Berg]

Btw, for debug I put

BUG_ON(atomic_read(&ht->nelems) < 0);

after the atomic_dec() in __rhashtable_remove_fast_one(). That makes
the kernel crash instantly on the buggy code, and I just have to run a
single test ("wpas_ctrl_interface_add_many") to get there.

johannes

Re: [v2 PATCH 0/2] rhashtable: rhashtable with duplicate objects

[Johannes Berg]

Btw, for debug I put

BUG_ON(atomic_read(&ht->nelems) < 0);

after the atomic_dec() in __rhashtable_remove_fast_one(). That makes
the kernel crash instantly on the buggy code, and I just have to run a
single test ("wpas_ctrl_interface_add_many") to get there.

johannes

Re: [v2 PATCH 0/2] rhashtable: rhashtable with duplicate objects

[Herbert Xu]

On Mon, Sep 19, 2016 at 12:10:27PM +0200, Johannes Berg wrote:
> Btw, for debug I put
> 
> BUG_ON(atomic_read(&ht->nelems) < 0);
> 
> after the atomic_dec() in __rhashtable_remove_fast_one(). That makes
> the kernel crash instantly on the buggy code, and I just have to run a
> single test ("wpas_ctrl_interface_add_many") to get there.

Aha I see the problem now.  The nelems logic on remove is broken.
I'll send out a v3.

Thanks!
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

Re: [v2 PATCH 0/2] rhashtable: rhashtable with duplicate objects

[Johannes Berg]

On Mon, 2016-09-19 at 18:48 +0800, Herbert Xu wrote:
> On Mon, Sep 19, 2016 at 12:10:27PM +0200, Johannes Berg wrote:
> > 
> > Btw, for debug I put
> > 
> > BUG_ON(atomic_read(&ht->nelems) < 0);
> > 
> > after the atomic_dec() in __rhashtable_remove_fast_one(). That
> > makes
> > the kernel crash instantly on the buggy code, and I just have to
> > run a
> > single test ("wpas_ctrl_interface_add_many") to get there.
> 
> Aha I see the problem now.  The nelems logic on remove is broken.

I looked at it for a long time, but didn't see it :) But yeah, I've
come to the same conclusion by adding debugging of the chains etc.

> I'll send out a v3.

I'll test it when I have it :)

johannes

Re: [v2 PATCH 0/2] rhashtable: rhashtable with duplicate objects

[Johannes Berg]

On Mon, 2016-09-19 at 18:48 +0800, Herbert Xu wrote:
> On Mon, Sep 19, 2016 at 12:10:27PM +0200, Johannes Berg wrote:
> > 
> > Btw, for debug I put
> > 
> > BUG_ON(atomic_read(&ht->nelems) < 0);
> > 
> > after the atomic_dec() in __rhashtable_remove_fast_one(). That
> > makes
> > the kernel crash instantly on the buggy code, and I just have to
> > run a
> > single test ("wpas_ctrl_interface_add_many") to get there.
> 
> Aha I see the problem now.  The nelems logic on remove is broken.

I looked at it for a long time, but didn't see it :) But yeah, I've
come to the same conclusion by adding debugging of the chains etc.

> I'll send out a v3.

I'll test it when I have it :)

johannes

[v3 PATCH 0/2] rhashtable: rhashtable with duplicate objects

[Herbert Xu]

v3 fixes a bug in the remove path that causes the element count
to decrease when it shouldn't, leading to a gigantic hash table
when it underflows.

v2 contains a reworked insertion slowpath to ensure that the
spinlock for the table we're inserting into is taken.

This series contains two patches.  The first adds the rhlist
interface and the second converts mac80211 to use it.  If this
works out I'll then proceed to convert the other insecure_elasticity
users over to this.

I've tested the rhlist code with test_rhashtable but I haven't
tested the mac80211 conversion.  So please give it a go and see
if it still works.

Thanks!
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

[v3 PATCH 0/2] rhashtable: rhashtable with duplicate objects

[Herbert Xu]

v3 fixes a bug in the remove path that causes the element count
to decrease when it shouldn't, leading to a gigantic hash table
when it underflows.

v2 contains a reworked insertion slowpath to ensure that the
spinlock for the table we're inserting into is taken.

This series contains two patches.  The first adds the rhlist
interface and the second converts mac80211 to use it.  If this
works out I'll then proceed to convert the other insecure_elasticity
users over to this.

I've tested the rhlist code with test_rhashtable but I haven't
tested the mac80211 conversion.  So please give it a go and see
if it still works.

Thanks!
-- 
Email: Herbert Xu <herbert-lOAM2aK0SrRLBo1qDEOMRrpzq4S04n8Q@public.gmane.org>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

[v3 PATCH 1/2] rhashtable: Add rhlist interface

[Herbert Xu]

The insecure_elasticity setting is an ugly wart brought out by
users who need to insert duplicate objects (that is, distinct
objects with identical keys) into the same table.

In fact, those users have a much bigger problem.  Once those
duplicate objects are inserted, they don't have an interface to
find them (unless you count the walker interface which walks
over the entire table).

Some users have resorted to doing a manual walk over the hash
table which is of course broken because they don't handle the
potential existence of multiple hash tables.  The result is that
they will break sporadically when they encounter a hash table
resize/rehash.

This patch provides a way out for those users, at the expense
of an extra pointer per object.  Essentially each object is now
a list of objects carrying the same key.  The hash table will
only see the lists so nothing changes as far as rhashtable is
concerned.

To use this new interface, you need to insert a struct rhlist_head
into your objects instead of struct rhash_head.  While the hash
table is unchanged, for type-safety you'll need to use struct
rhltable instead of struct rhashtable.  All the existing interfaces
have been duplicated for rhlist, including the hash table walker.

One missing feature is nulls marking because AFAIK the only potential
user of it does not need duplicate objects.  Should anyone need
this it shouldn't be too hard to add.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
---

 include/linux/rhashtable.h |  491 ++++++++++++++++++++++++++++++++++-----------
 lib/rhashtable.c           |  258 ++++++++++++++++++-----
 2 files changed, 583 insertions(+), 166 deletions(-)

diff --git a/include/linux/rhashtable.h b/include/linux/rhashtable.h
index fd82584..5c132d3 100644
--- a/include/linux/rhashtable.h
+++ b/include/linux/rhashtable.h
@@ -1,7 +1,7 @@
 /*
  * Resizable, Scalable, Concurrent Hash Table
  *
- * Copyright (c) 2015 Herbert Xu <herbert@gondor.apana.org.au>
+ * Copyright (c) 2015-2016 Herbert Xu <herbert@gondor.apana.org.au>
  * Copyright (c) 2014-2015 Thomas Graf <tgraf@suug.ch>
  * Copyright (c) 2008-2014 Patrick McHardy <kaber@trash.net>
  *
@@ -53,6 +53,11 @@ struct rhash_head {
 	struct rhash_head __rcu		*next;
 };
 
+struct rhlist_head {
+	struct rhash_head		rhead;
+	struct rhlist_head __rcu	*next;
+};
+
 /**
  * struct bucket_table - Table of hash buckets
  * @size: Number of hash buckets
@@ -137,6 +142,7 @@ struct rhashtable_params {
  * @key_len: Key length for hashfn
  * @elasticity: Maximum chain length before rehash
  * @p: Configuration parameters
+ * @rhlist: True if this is an rhltable
  * @run_work: Deferred worker to expand/shrink asynchronously
  * @mutex: Mutex to protect current/future table swapping
  * @lock: Spin lock to protect walker list
@@ -147,12 +153,21 @@ struct rhashtable {
 	unsigned int			key_len;
 	unsigned int			elasticity;
 	struct rhashtable_params	p;
+	bool				rhlist;
 	struct work_struct		run_work;
 	struct mutex                    mutex;
 	spinlock_t			lock;
 };
 
 /**
+ * struct rhltable - Hash table with duplicate objects in a list
+ * @ht: Underlying rhtable
+ */
+struct rhltable {
+	struct rhashtable ht;
+};
+
+/**
  * struct rhashtable_walker - Hash table walker
  * @list: List entry on list of walkers
  * @tbl: The table that we were walking over
@@ -163,9 +178,10 @@ struct rhashtable_walker {
 };
 
 /**
- * struct rhashtable_iter - Hash table iterator, fits into netlink cb
+ * struct rhashtable_iter - Hash table iterator
  * @ht: Table to iterate through
  * @p: Current pointer
+ * @list: Current hash list pointer
  * @walker: Associated rhashtable walker
  * @slot: Current slot
  * @skip: Number of entries to skip in slot
@@ -173,6 +189,7 @@ struct rhashtable_walker {
 struct rhashtable_iter {
 	struct rhashtable *ht;
 	struct rhash_head *p;
+	struct rhlist_head *list;
 	struct rhashtable_walker walker;
 	unsigned int slot;
 	unsigned int skip;
@@ -339,13 +356,11 @@ static inline int lockdep_rht_bucket_is_held(const struct bucket_table *tbl,
 
 int rhashtable_init(struct rhashtable *ht,
 		    const struct rhashtable_params *params);
+int rhltable_init(struct rhltable *hlt,
+		  const struct rhashtable_params *params);
 
-struct bucket_table *rhashtable_insert_slow(struct rhashtable *ht,
-					    const void *key,
-					    struct rhash_head *obj,
-					    struct bucket_table *old_tbl,
-					    void **data);
-int rhashtable_insert_rehash(struct rhashtable *ht, struct bucket_table *tbl);
+void *rhashtable_insert_slow(struct rhashtable *ht, const void *key,
+			     struct rhash_head *obj);
 
 void rhashtable_walk_enter(struct rhashtable *ht,
 			   struct rhashtable_iter *iter);
@@ -507,6 +522,31 @@ void rhashtable_destroy(struct rhashtable *ht);
 	rht_for_each_entry_rcu_continue(tpos, pos, (tbl)->buckets[hash],\
 					tbl, hash, member)
 
+/**
+ * rhl_for_each_rcu - iterate over rcu hash table list
+ * @pos:	the &struct rlist_head to use as a loop cursor.
+ * @list:	the head of the list
+ *
+ * This hash chain list-traversal primitive should be used on the
+ * list returned by rhltable_lookup.
+ */
+#define rhl_for_each_rcu(pos, list)					\
+	for (pos = list; pos; pos = rcu_dereference_raw(pos->next))
+
+/**
+ * rhl_for_each_entry_rcu - iterate over rcu hash table list of given type
+ * @tpos:	the type * to use as a loop cursor.
+ * @pos:	the &struct rlist_head to use as a loop cursor.
+ * @list:	the head of the list
+ * @member:	name of the &struct rlist_head within the hashable struct.
+ *
+ * This hash chain list-traversal primitive should be used on the
+ * list returned by rhltable_lookup.
+ */
+#define rhl_for_each_entry_rcu(tpos, pos, list, member)			\
+	for (pos = list; pos && rht_entry(tpos, pos, member);		\
+	     pos = rcu_dereference_raw(pos->next))
+
 static inline int rhashtable_compare(struct rhashtable_compare_arg *arg,
 				     const void *obj)
 {
@@ -516,18 +556,8 @@ static inline int rhashtable_compare(struct rhashtable_compare_arg *arg,
 	return memcmp(ptr + ht->p.key_offset, arg->key, ht->p.key_len);
 }
 
-/**
- * rhashtable_lookup_fast - search hash table, inlined version
- * @ht:		hash table
- * @key:	the pointer to the key
- * @params:	hash table parameters
- *
- * Computes the hash value for the key and traverses the bucket chain looking
- * for a entry with an identical key. The first matching entry is returned.
- *
- * Returns the first entry on which the compare function returned true.
- */
-static inline void *rhashtable_lookup_fast(
+/* Internal function, do not use. */
+static inline struct rhash_head *__rhashtable_lookup(
 	struct rhashtable *ht, const void *key,
 	const struct rhashtable_params params)
 {
@@ -539,8 +569,6 @@ static inline void *rhashtable_lookup_fast(
 	struct rhash_head *he;
 	unsigned int hash;
 
-	rcu_read_lock();
-
 	tbl = rht_dereference_rcu(ht->tbl, ht);
 restart:
 	hash = rht_key_hashfn(ht, tbl, key, params);
@@ -549,8 +577,7 @@ restart:
 		    params.obj_cmpfn(&arg, rht_obj(ht, he)) :
 		    rhashtable_compare(&arg, rht_obj(ht, he)))
 			continue;
-		rcu_read_unlock();
-		return rht_obj(ht, he);
+		return he;
 	}
 
 	/* Ensure we see any new tables. */
@@ -559,96 +586,165 @@ restart:
 	tbl = rht_dereference_rcu(tbl->future_tbl, ht);
 	if (unlikely(tbl))
 		goto restart;
-	rcu_read_unlock();
 
 	return NULL;
 }
 
+/**
+ * rhashtable_lookup - search hash table
+ * @ht:		hash table
+ * @key:	the pointer to the key
+ * @params:	hash table parameters
+ *
+ * Computes the hash value for the key and traverses the bucket chain looking
+ * for a entry with an identical key. The first matching entry is returned.
+ *
+ * This must only be called under the RCU read lock.
+ *
+ * Returns the first entry on which the compare function returned true.
+ */
+static inline void *rhashtable_lookup(
+	struct rhashtable *ht, const void *key,
+	const struct rhashtable_params params)
+{
+	struct rhash_head *he = __rhashtable_lookup(ht, key, params);
+
+	return he ? rht_obj(ht, he) : NULL;
+}
+
+/**
+ * rhashtable_lookup_fast - search hash table, without RCU read lock
+ * @ht:		hash table
+ * @key:	the pointer to the key
+ * @params:	hash table parameters
+ *
+ * Computes the hash value for the key and traverses the bucket chain looking
+ * for a entry with an identical key. The first matching entry is returned.
+ *
+ * Only use this function when you have other mechanisms guaranteeing
+ * that the object won't go away after the RCU read lock is released.
+ *
+ * Returns the first entry on which the compare function returned true.
+ */
+static inline void *rhashtable_lookup_fast(
+	struct rhashtable *ht, const void *key,
+	const struct rhashtable_params params)
+{
+	void *obj;
+
+	rcu_read_lock();
+	obj = rhashtable_lookup(ht, key, params);
+	rcu_read_unlock();
+
+	return obj;
+}
+
+/**
+ * rhltable_lookup - search hash list table
+ * @hlt:	hash table
+ * @key:	the pointer to the key
+ * @params:	hash table parameters
+ *
+ * Computes the hash value for the key and traverses the bucket chain looking
+ * for a entry with an identical key.  All matching entries are returned
+ * in a list.
+ *
+ * This must only be called under the RCU read lock.
+ *
+ * Returns the list of entries that match the given key.
+ */
+static inline struct rhlist_head *rhltable_lookup(
+	struct rhltable *hlt, const void *key,
+	const struct rhashtable_params params)
+{
+	struct rhash_head *he = __rhashtable_lookup(&hlt->ht, key, params);
+
+	return he ? container_of(he, struct rhlist_head, rhead) : NULL;
+}
+
 /* Internal function, please use rhashtable_insert_fast() instead. This
  * function returns the existing element already in hashes in there is a clash,
  * otherwise it returns an error via ERR_PTR().
  */
 static inline void *__rhashtable_insert_fast(
 	struct rhashtable *ht, const void *key, struct rhash_head *obj,
-	const struct rhashtable_params params)
+	const struct rhashtable_params params, bool rhlist)
 {
 	struct rhashtable_compare_arg arg = {
 		.ht = ht,
 		.key = key,
 	};
-	struct bucket_table *tbl, *new_tbl;
+	struct rhash_head __rcu **pprev;
+	struct bucket_table *tbl;
 	struct rhash_head *head;
 	spinlock_t *lock;
-	unsigned int elasticity;
 	unsigned int hash;
-	void *data = NULL;
-	int err;
+	int elasticity;
+	void *data;
 
-restart:
 	rcu_read_lock();
 
 	tbl = rht_dereference_rcu(ht->tbl, ht);
+	hash = rht_head_hashfn(ht, tbl, obj, params);
+	lock = rht_bucket_lock(tbl, hash);
+	spin_lock_bh(lock);
 
-	/* All insertions must grab the oldest table containing
-	 * the hashed bucket that is yet to be rehashed.
-	 */
-	for (;;) {
-		hash = rht_head_hashfn(ht, tbl, obj, params);
-		lock = rht_bucket_lock(tbl, hash);
-		spin_lock_bh(lock);
-
-		if (tbl->rehash <= hash)
-			break;
-
+	if (unlikely(rht_dereference_bucket(tbl->future_tbl, tbl, hash))) {
+slow_path:
 		spin_unlock_bh(lock);
-		tbl = rht_dereference_rcu(tbl->future_tbl, ht);
+		rcu_read_unlock();
+		return rhashtable_insert_slow(ht, key, obj);
 	}
 
-	new_tbl = rht_dereference_rcu(tbl->future_tbl, ht);
-	if (unlikely(new_tbl)) {
-		tbl = rhashtable_insert_slow(ht, key, obj, new_tbl, &data);
-		if (!IS_ERR_OR_NULL(tbl))
-			goto slow_path;
+	elasticity = ht->elasticity;
+	pprev = &tbl->buckets[hash];
+	rht_for_each(head, tbl, hash) {
+		struct rhlist_head *plist;
+		struct rhlist_head *list;
+
+		elasticity--;
+		if (!key ||
+		    (params.obj_cmpfn ?
+		     params.obj_cmpfn(&arg, rht_obj(ht, head)) :
+		     rhashtable_compare(&arg, rht_obj(ht, head))))
+			continue;
+
+		data = rht_obj(ht, head);
 
-		err = PTR_ERR(tbl);
-		if (err == -EEXIST)
-			err = 0;
+		if (!rhlist)
+			goto out;
 
-		goto out;
-	}
 
-	err = -E2BIG;
-	if (unlikely(rht_grow_above_max(ht, tbl)))
-		goto out;
+		list = container_of(obj, struct rhlist_head, rhead);
+		plist = container_of(head, struct rhlist_head, rhead);
 
-	if (unlikely(rht_grow_above_100(ht, tbl))) {
-slow_path:
-		spin_unlock_bh(lock);
-		err = rhashtable_insert_rehash(ht, tbl);
-		rcu_read_unlock();
-		if (err)
-			return ERR_PTR(err);
+		RCU_INIT_POINTER(list->next, plist);
+		head = rht_dereference_bucket(head->next, tbl, hash);
+		RCU_INIT_POINTER(list->rhead.next, head);
+		rcu_assign_pointer(*pprev, obj);
 
-		goto restart;
+		goto good;
 	}
 
-	err = 0;
-	elasticity = ht->elasticity;
-	rht_for_each(head, tbl, hash) {
-		if (key &&
-		    unlikely(!(params.obj_cmpfn ?
-			       params.obj_cmpfn(&arg, rht_obj(ht, head)) :
-			       rhashtable_compare(&arg, rht_obj(ht, head))))) {
-			data = rht_obj(ht, head);
-			goto out;
-		}
-		if (!--elasticity)
-			goto slow_path;
-	}
+	if (elasticity <= 0)
+		goto slow_path;
+
+	data = ERR_PTR(-E2BIG);
+	if (unlikely(rht_grow_above_max(ht, tbl)))
+		goto out;
+
+	if (unlikely(rht_grow_above_100(ht, tbl)))
+		goto slow_path;
 
 	head = rht_dereference_bucket(tbl->buckets[hash], tbl, hash);
 
 	RCU_INIT_POINTER(obj->next, head);
+	if (rhlist) {
+		struct rhlist_head *list;
+
+		list = container_of(obj, struct rhlist_head, rhead);
+		RCU_INIT_POINTER(list->next, NULL);
+	}
 
 	rcu_assign_pointer(tbl->buckets[hash], obj);
 
@@ -656,11 +752,14 @@ slow_path:
 	if (rht_grow_above_75(ht, tbl))
 		schedule_work(&ht->run_work);
 
+good:
+	data = NULL;
+
 out:
 	spin_unlock_bh(lock);
 	rcu_read_unlock();
 
-	return err ? ERR_PTR(err) : data;
+	return data;
 }
 
 /**
@@ -685,7 +784,7 @@ static inline int rhashtable_insert_fast(
 {
 	void *ret;
 
-	ret = __rhashtable_insert_fast(ht, NULL, obj, params);
+	ret = __rhashtable_insert_fast(ht, NULL, obj, params, false);
 	if (IS_ERR(ret))
 		return PTR_ERR(ret);
 
@@ -693,6 +792,58 @@ static inline int rhashtable_insert_fast(
 }
 
 /**
+ * rhltable_insert_key - insert object into hash list table
+ * @hlt:	hash list table
+ * @key:	the pointer to the key
+ * @list:	pointer to hash list head inside object
+ * @params:	hash table parameters
+ *
+ * Will take a per bucket spinlock to protect against mutual mutations
+ * on the same bucket. Multiple insertions may occur in parallel unless
+ * they map to the same bucket lock.
+ *
+ * It is safe to call this function from atomic context.
+ *
+ * Will trigger an automatic deferred table resizing if the size grows
+ * beyond the watermark indicated by grow_decision() which can be passed
+ * to rhashtable_init().
+ */
+static inline int rhltable_insert_key(
+	struct rhltable *hlt, const void *key, struct rhlist_head *list,
+	const struct rhashtable_params params)
+{
+	return PTR_ERR(__rhashtable_insert_fast(&hlt->ht, key, &list->rhead,
+						params, true));
+}
+
+/**
+ * rhltable_insert - insert object into hash list table
+ * @hlt:	hash list table
+ * @list:	pointer to hash list head inside object
+ * @params:	hash table parameters
+ *
+ * Will take a per bucket spinlock to protect against mutual mutations
+ * on the same bucket. Multiple insertions may occur in parallel unless
+ * they map to the same bucket lock.
+ *
+ * It is safe to call this function from atomic context.
+ *
+ * Will trigger an automatic deferred table resizing if the size grows
+ * beyond the watermark indicated by grow_decision() which can be passed
+ * to rhashtable_init().
+ */
+static inline int rhltable_insert(
+	struct rhltable *hlt, struct rhlist_head *list,
+	const struct rhashtable_params params)
+{
+	const char *key = rht_obj(&hlt->ht, &list->rhead);
+
+	key += params.key_offset;
+
+	return rhltable_insert_key(hlt, key, list, params);
+}
+
+/**
  * rhashtable_lookup_insert_fast - lookup and insert object into hash table
  * @ht:		hash table
  * @obj:	pointer to hash head inside object
@@ -722,7 +873,8 @@ static inline int rhashtable_lookup_insert_fast(
 
 	BUG_ON(ht->p.obj_hashfn);
 
-	ret = __rhashtable_insert_fast(ht, key + ht->p.key_offset, obj, params);
+	ret = __rhashtable_insert_fast(ht, key + ht->p.key_offset, obj, params,
+				       false);
 	if (IS_ERR(ret))
 		return PTR_ERR(ret);
 
@@ -759,7 +911,7 @@ static inline int rhashtable_lookup_insert_key(
 
 	BUG_ON(!ht->p.obj_hashfn || !key);
 
-	ret = __rhashtable_insert_fast(ht, key, obj, params);
+	ret = __rhashtable_insert_fast(ht, key, obj, params, false);
 	if (IS_ERR(ret))
 		return PTR_ERR(ret);
 
@@ -783,13 +935,14 @@ static inline void *rhashtable_lookup_get_insert_key(
 {
 	BUG_ON(!ht->p.obj_hashfn || !key);
 
-	return __rhashtable_insert_fast(ht, key, obj, params);
+	return __rhashtable_insert_fast(ht, key, obj, params, false);
 }
 
 /* Internal function, please use rhashtable_remove_fast() instead */
-static inline int __rhashtable_remove_fast(
+static inline int __rhashtable_remove_fast_one(
 	struct rhashtable *ht, struct bucket_table *tbl,
-	struct rhash_head *obj, const struct rhashtable_params params)
+	struct rhash_head *obj, const struct rhashtable_params params,
+	bool rhlist)
 {
 	struct rhash_head __rcu **pprev;
 	struct rhash_head *he;
@@ -804,39 +957,66 @@ static inline int __rhashtable_remove_fast(
 
 	pprev = &tbl->buckets[hash];
 	rht_for_each(he, tbl, hash) {
+		struct rhlist_head *list;
+
+		list = container_of(he, struct rhlist_head, rhead);
+
 		if (he != obj) {
+			struct rhlist_head __rcu **lpprev;
+
 			pprev = &he->next;
-			continue;
+
+			if (!rhlist)
+				continue;
+
+			do {
+				lpprev = &list->next;
+				list = rht_dereference_bucket(list->next,
+							      tbl, hash);
+			} while (list && obj != &list->rhead);
+
+			if (!list)
+				continue;
+
+			list = rht_dereference_bucket(list->next, tbl, hash);
+			RCU_INIT_POINTER(*lpprev, list);
+			err = 0;
+			break;
 		}
 
-		rcu_assign_pointer(*pprev, obj->next);
-		err = 0;
+		obj = rht_dereference_bucket(obj->next, tbl, hash);
+		err = 1;
+
+		if (rhlist) {
+			list = rht_dereference_bucket(list->next, tbl, hash);
+			if (list) {
+				RCU_INIT_POINTER(list->rhead.next, obj);
+				obj = &list->rhead;
+				err = 0;
+			}
+		}
+
+		rcu_assign_pointer(*pprev, obj);
 		break;
 	}
 
 	spin_unlock_bh(lock);
 
+	if (err > 0) {
+		atomic_dec(&ht->nelems);
+		if (unlikely(ht->p.automatic_shrinking &&
+			     rht_shrink_below_30(ht, tbl)))
+			schedule_work(&ht->run_work);
+		err = 0;
+	}
+
 	return err;
 }
 
-/**
- * rhashtable_remove_fast - remove object from hash table
- * @ht:		hash table
- * @obj:	pointer to hash head inside object
- * @params:	hash table parameters
- *
- * Since the hash chain is single linked, the removal operation needs to
- * walk the bucket chain upon removal. The removal operation is thus
- * considerable slow if the hash table is not correctly sized.
- *
- * Will automatically shrink the table via rhashtable_expand() if the
- * shrink_decision function specified at rhashtable_init() returns true.
- *
- * Returns zero on success, -ENOENT if the entry could not be found.
- */
-static inline int rhashtable_remove_fast(
+/* Internal function, please use rhashtable_remove_fast() instead */
+static inline int __rhashtable_remove_fast(
 	struct rhashtable *ht, struct rhash_head *obj,
-	const struct rhashtable_params params)
+	const struct rhashtable_params params, bool rhlist)
 {
 	struct bucket_table *tbl;
 	int err;
@@ -850,24 +1030,60 @@ static inline int rhashtable_remove_fast(
 	 * visible then that guarantees the entry to still be in
 	 * the old tbl if it exists.
 	 */
-	while ((err = __rhashtable_remove_fast(ht, tbl, obj, params)) &&
+	while ((err = __rhashtable_remove_fast_one(ht, tbl, obj, params,
+						   rhlist)) &&
 	       (tbl = rht_dereference_rcu(tbl->future_tbl, ht)))
 		;
 
-	if (err)
-		goto out;
-
-	atomic_dec(&ht->nelems);
-	if (unlikely(ht->p.automatic_shrinking &&
-		     rht_shrink_below_30(ht, tbl)))
-		schedule_work(&ht->run_work);
-
-out:
 	rcu_read_unlock();
 
 	return err;
 }
 
+/**
+ * rhashtable_remove_fast - remove object from hash table
+ * @ht:		hash table
+ * @obj:	pointer to hash head inside object
+ * @params:	hash table parameters
+ *
+ * Since the hash chain is single linked, the removal operation needs to
+ * walk the bucket chain upon removal. The removal operation is thus
+ * considerable slow if the hash table is not correctly sized.
+ *
+ * Will automatically shrink the table via rhashtable_expand() if the
+ * shrink_decision function specified at rhashtable_init() returns true.
+ *
+ * Returns zero on success, -ENOENT if the entry could not be found.
+ */
+static inline int rhashtable_remove_fast(
+	struct rhashtable *ht, struct rhash_head *obj,
+	const struct rhashtable_params params)
+{
+	return __rhashtable_remove_fast(ht, obj, params, false);
+}
+
+/**
+ * rhltable_remove - remove object from hash list table
+ * @hlt:	hash list table
+ * @list:	pointer to hash list head inside object
+ * @params:	hash table parameters
+ *
+ * Since the hash chain is single linked, the removal operation needs to
+ * walk the bucket chain upon removal. The removal operation is thus
+ * considerable slow if the hash table is not correctly sized.
+ *
+ * Will automatically shrink the table via rhashtable_expand() if the
+ * shrink_decision function specified at rhashtable_init() returns true.
+ *
+ * Returns zero on success, -ENOENT if the entry could not be found.
+ */
+static inline int rhltable_remove(
+	struct rhltable *hlt, struct rhlist_head *list,
+	const struct rhashtable_params params)
+{
+	return __rhashtable_remove_fast(&hlt->ht, &list->rhead, params, true);
+}
+
 /* Internal function, please use rhashtable_replace_fast() instead */
 static inline int __rhashtable_replace_fast(
 	struct rhashtable *ht, struct bucket_table *tbl,
@@ -958,4 +1174,51 @@ static inline int rhashtable_walk_init(struct rhashtable *ht,
 	return 0;
 }
 
+/**
+ * rhltable_walk_enter - Initialise an iterator
+ * @hlt:	Table to walk over
+ * @iter:	Hash table Iterator
+ *
+ * This function prepares a hash table walk.
+ *
+ * Note that if you restart a walk after rhashtable_walk_stop you
+ * may see the same object twice.  Also, you may miss objects if
+ * there are removals in between rhashtable_walk_stop and the next
+ * call to rhashtable_walk_start.
+ *
+ * For a completely stable walk you should construct your own data
+ * structure outside the hash table.
+ *
+ * This function may sleep so you must not call it from interrupt
+ * context or with spin locks held.
+ *
+ * You must call rhashtable_walk_exit after this function returns.
+ */
+static inline void rhltable_walk_enter(struct rhltable *hlt,
+				       struct rhashtable_iter *iter)
+{
+	return rhashtable_walk_enter(&hlt->ht, iter);
+}
+
+/**
+ * rhltable_free_and_destroy - free elements and destroy hash list table
+ * @hlt:	the hash list table to destroy
+ * @free_fn:	callback to release resources of element
+ * @arg:	pointer passed to free_fn
+ *
+ * See documentation for rhashtable_free_and_destroy.
+ */
+static inline void rhltable_free_and_destroy(struct rhltable *hlt,
+					     void (*free_fn)(void *ptr,
+							     void *arg),
+					     void *arg)
+{
+	return rhashtable_free_and_destroy(&hlt->ht, free_fn, arg);
+}
+
+static inline void rhltable_destroy(struct rhltable *hlt)
+{
+	return rhltable_free_and_destroy(hlt, NULL, NULL);
+}
+
 #endif /* _LINUX_RHASHTABLE_H */
diff --git a/lib/rhashtable.c b/lib/rhashtable.c
index 06c2872..32d0ad0 100644
--- a/lib/rhashtable.c
+++ b/lib/rhashtable.c
@@ -378,22 +378,8 @@ static void rht_deferred_worker(struct work_struct *work)
 		schedule_work(&ht->run_work);
 }
 
-static bool rhashtable_check_elasticity(struct rhashtable *ht,
-					struct bucket_table *tbl,
-					unsigned int hash)
-{
-	unsigned int elasticity = ht->elasticity;
-	struct rhash_head *head;
-
-	rht_for_each(head, tbl, hash)
-		if (!--elasticity)
-			return true;
-
-	return false;
-}
-
-int rhashtable_insert_rehash(struct rhashtable *ht,
-			     struct bucket_table *tbl)
+static int rhashtable_insert_rehash(struct rhashtable *ht,
+				    struct bucket_table *tbl)
 {
 	struct bucket_table *old_tbl;
 	struct bucket_table *new_tbl;
@@ -439,57 +425,165 @@ fail:
 
 	return err;
 }
-EXPORT_SYMBOL_GPL(rhashtable_insert_rehash);
 
-struct bucket_table *rhashtable_insert_slow(struct rhashtable *ht,
-					    const void *key,
-					    struct rhash_head *obj,
-					    struct bucket_table *tbl,
-					    void **data)
+static void *rhashtable_lookup_one(struct rhashtable *ht,
+				   struct bucket_table *tbl, unsigned int hash,
+				   const void *key, struct rhash_head *obj)
 {
+	struct rhashtable_compare_arg arg = {
+		.ht = ht,
+		.key = key,
+	};
+	struct rhash_head __rcu **pprev;
 	struct rhash_head *head;
-	unsigned int hash;
-	int err;
+	int elasticity;
 
-	tbl = rhashtable_last_table(ht, tbl);
-	hash = head_hashfn(ht, tbl, obj);
-	spin_lock_nested(rht_bucket_lock(tbl, hash), SINGLE_DEPTH_NESTING);
-
-	err = -EEXIST;
-	if (key) {
-		*data = rhashtable_lookup_fast(ht, key, ht->p);
-		if (*data)
-			goto exit;
+	elasticity = ht->elasticity;
+	pprev = &tbl->buckets[hash];
+	rht_for_each(head, tbl, hash) {
+		struct rhlist_head *list;
+		struct rhlist_head *plist;
+
+		elasticity--;
+		if (!key ||
+		    (ht->p.obj_cmpfn ?
+		     ht->p.obj_cmpfn(&arg, rht_obj(ht, head)) :
+		     rhashtable_compare(&arg, rht_obj(ht, head))))
+			continue;
+
+		if (!ht->rhlist)
+			return rht_obj(ht, head);
+
+		list = container_of(obj, struct rhlist_head, rhead);
+		plist = container_of(head, struct rhlist_head, rhead);
+
+		RCU_INIT_POINTER(list->next, plist);
+		head = rht_dereference_bucket(head->next, tbl, hash);
+		RCU_INIT_POINTER(list->rhead.next, head);
+		rcu_assign_pointer(*pprev, obj);
+
+		return NULL;
 	}
 
-	err = -E2BIG;
-	if (unlikely(rht_grow_above_max(ht, tbl)))
-		goto exit;
+	if (elasticity <= 0)
+		return ERR_PTR(-EAGAIN);
+
+	return ERR_PTR(-ENOENT);
+}
+
+static struct bucket_table *rhashtable_insert_one(struct rhashtable *ht,
+						  struct bucket_table *tbl,
+						  unsigned int hash,
+						  struct rhash_head *obj,
+						  void *data)
+{
+	struct bucket_table *new_tbl;
+	struct rhash_head *head;
+
+	if (!IS_ERR_OR_NULL(data))
+		return ERR_PTR(-EEXIST);
 
-	err = -EAGAIN;
-	if (rhashtable_check_elasticity(ht, tbl, hash) ||
-	    rht_grow_above_100(ht, tbl))
-		goto exit;
+	if (PTR_ERR(data) != -EAGAIN && PTR_ERR(data) != -ENOENT)
+		return ERR_CAST(data);
 
-	err = 0;
+	new_tbl = rcu_dereference(tbl->future_tbl);
+	if (new_tbl)
+		return new_tbl;
+
+	if (PTR_ERR(data) != -ENOENT)
+		return ERR_CAST(data);
+
+	if (unlikely(rht_grow_above_max(ht, tbl)))
+		return ERR_PTR(-E2BIG);
+
+	if (unlikely(rht_grow_above_100(ht, tbl)))
+		return ERR_PTR(-EAGAIN);
 
 	head = rht_dereference_bucket(tbl->buckets[hash], tbl, hash);
 
 	RCU_INIT_POINTER(obj->next, head);
+	if (ht->rhlist) {
+		struct rhlist_head *list;
+
+		list = container_of(obj, struct rhlist_head, rhead);
+		RCU_INIT_POINTER(list->next, NULL);
+	}
 
 	rcu_assign_pointer(tbl->buckets[hash], obj);
 
 	atomic_inc(&ht->nelems);
+	if (rht_grow_above_75(ht, tbl))
+		schedule_work(&ht->run_work);
 
-exit:
-	spin_unlock(rht_bucket_lock(tbl, hash));
+	return NULL;
+}
 
-	if (err == 0)
-		return NULL;
-	else if (err == -EAGAIN)
-		return tbl;
-	else
-		return ERR_PTR(err);
+static void *rhashtable_try_insert(struct rhashtable *ht, const void *key,
+				   struct rhash_head *obj)
+{
+	struct bucket_table *new_tbl;
+	struct bucket_table *tbl;
+	unsigned int hash;
+	spinlock_t *lock;
+	void *data;
+
+	tbl = rcu_dereference(ht->tbl);
+
+	/* All insertions must grab the oldest table containing
+	 * the hashed bucket that is yet to be rehashed.
+	 */
+	for (;;) {
+		hash = rht_head_hashfn(ht, tbl, obj, ht->p);
+		lock = rht_bucket_lock(tbl, hash);
+		spin_lock_bh(lock);
+
+		if (tbl->rehash <= hash)
+			break;
+
+		spin_unlock_bh(lock);
+		tbl = rcu_dereference(tbl->future_tbl);
+	}
+
+	data = rhashtable_lookup_one(ht, tbl, hash, key, obj);
+	new_tbl = rhashtable_insert_one(ht, tbl, hash, obj, data);
+	if (PTR_ERR(new_tbl) != -EEXIST)
+		data = ERR_CAST(new_tbl);
+
+	while (!IS_ERR_OR_NULL(new_tbl)) {
+		tbl = new_tbl;
+		hash = rht_head_hashfn(ht, tbl, obj, ht->p);
+		spin_lock_nested(rht_bucket_lock(tbl, hash),
+				 SINGLE_DEPTH_NESTING);
+
+		data = rhashtable_lookup_one(ht, tbl, hash, key, obj);
+		new_tbl = rhashtable_insert_one(ht, tbl, hash, obj, data);
+		if (PTR_ERR(new_tbl) != -EEXIST)
+			data = ERR_CAST(new_tbl);
+
+		spin_unlock(rht_bucket_lock(tbl, hash));
+	}
+
+	spin_unlock_bh(lock);
+
+	if (PTR_ERR(data) == -EAGAIN)
+		data = ERR_PTR(rhashtable_insert_rehash(ht, tbl) ?:
+			       -EAGAIN);
+
+	return data;
+}
+
+void *rhashtable_insert_slow(struct rhashtable *ht, const void *key,
+			     struct rhash_head *obj)
+{
+	void *data;
+
+	do {
+		rcu_read_lock();
+		data = rhashtable_try_insert(ht, key, obj);
+		rcu_read_unlock();
+	} while (PTR_ERR(data) == -EAGAIN);
+
+	return data;
 }
 EXPORT_SYMBOL_GPL(rhashtable_insert_slow);
 
@@ -593,11 +687,16 @@ EXPORT_SYMBOL_GPL(rhashtable_walk_start);
 void *rhashtable_walk_next(struct rhashtable_iter *iter)
 {
 	struct bucket_table *tbl = iter->walker.tbl;
+	struct rhlist_head *list = iter->list;
 	struct rhashtable *ht = iter->ht;
 	struct rhash_head *p = iter->p;
+	bool rhlist = ht->rhlist;
 
 	if (p) {
-		p = rht_dereference_bucket_rcu(p->next, tbl, iter->slot);
+		if (!rhlist || !(list = rcu_dereference(list->next))) {
+			p = rcu_dereference(p->next);
+			list = container_of(p, struct rhlist_head, rhead);
+		}
 		goto next;
 	}
 
@@ -605,6 +704,18 @@ void *rhashtable_walk_next(struct rhashtable_iter *iter)
 		int skip = iter->skip;
 
 		rht_for_each_rcu(p, tbl, iter->slot) {
+			if (rhlist) {
+				list = container_of(p, struct rhlist_head,
+						    rhead);
+				do {
+					if (!skip)
+						goto next;
+					skip--;
+					list = rcu_dereference(list->next);
+				} while (list);
+
+				continue;
+			}
 			if (!skip)
 				break;
 			skip--;
@@ -614,7 +725,8 @@ next:
 		if (!rht_is_a_nulls(p)) {
 			iter->skip++;
 			iter->p = p;
-			return rht_obj(ht, p);
+			iter->list = list;
+			return rht_obj(ht, rhlist ? &list->rhead : p);
 		}
 
 		iter->skip = 0;
@@ -803,6 +915,48 @@ int rhashtable_init(struct rhashtable *ht,
 EXPORT_SYMBOL_GPL(rhashtable_init);
 
 /**
+ * rhltable_init - initialize a new hash list table
+ * @hlt:	hash list table to be initialized
+ * @params:	configuration parameters
+ *
+ * Initializes a new hash list table.
+ *
+ * See documentation for rhashtable_init.
+ */
+int rhltable_init(struct rhltable *hlt, const struct rhashtable_params *params)
+{
+	int err;
+
+	/* No rhlist NULLs marking for now. */
+	if (params->nulls_base)
+		return -EINVAL;
+
+	err = rhashtable_init(&hlt->ht, params);
+	hlt->ht.rhlist = true;
+	return err;
+}
+EXPORT_SYMBOL_GPL(rhltable_init);
+
+static void rhashtable_free_one(struct rhashtable *ht, struct rhash_head *obj,
+				void (*free_fn)(void *ptr, void *arg),
+				void *arg)
+{
+	struct rhlist_head *list;
+
+	if (!ht->rhlist) {
+		free_fn(rht_obj(ht, obj), arg);
+		return;
+	}
+
+	list = container_of(obj, struct rhlist_head, rhead);
+	do {
+		obj = &list->rhead;
+		list = rht_dereference(list->next, ht);
+		free_fn(rht_obj(ht, obj), arg);
+	} while (list);
+}
+
+/**
  * rhashtable_free_and_destroy - free elements and destroy hash table
  * @ht:		the hash table to destroy
  * @free_fn:	callback to release resources of element
@@ -839,7 +993,7 @@ void rhashtable_free_and_destroy(struct rhashtable *ht,
 			     pos = next,
 			     next = !rht_is_a_nulls(pos) ?
 					rht_dereference(pos->next, ht) : NULL)
-				free_fn(rht_obj(ht, pos), arg);
+				rhashtable_free_one(ht, pos, free_fn, arg);
 		}
 	}
 

[v3 PATCH 1/2] rhashtable: Add rhlist interface

[Herbert Xu]

The insecure_elasticity setting is an ugly wart brought out by
users who need to insert duplicate objects (that is, distinct
objects with identical keys) into the same table.

In fact, those users have a much bigger problem.  Once those
duplicate objects are inserted, they don't have an interface to
find them (unless you count the walker interface which walks
over the entire table).

Some users have resorted to doing a manual walk over the hash
table which is of course broken because they don't handle the
potential existence of multiple hash tables.  The result is that
they will break sporadically when they encounter a hash table
resize/rehash.

This patch provides a way out for those users, at the expense
of an extra pointer per object.  Essentially each object is now
a list of objects carrying the same key.  The hash table will
only see the lists so nothing changes as far as rhashtable is
concerned.

To use this new interface, you need to insert a struct rhlist_head
into your objects instead of struct rhash_head.  While the hash
table is unchanged, for type-safety you'll need to use struct
rhltable instead of struct rhashtable.  All the existing interfaces
have been duplicated for rhlist, including the hash table walker.

One missing feature is nulls marking because AFAIK the only potential
user of it does not need duplicate objects.  Should anyone need
this it shouldn't be too hard to add.

Signed-off-by: Herbert Xu <herbert-lOAM2aK0SrRLBo1qDEOMRrpzq4S04n8Q@public.gmane.org>
---

 include/linux/rhashtable.h |  491 ++++++++++++++++++++++++++++++++++-----------
 lib/rhashtable.c           |  258 ++++++++++++++++++-----
 2 files changed, 583 insertions(+), 166 deletions(-)

diff --git a/include/linux/rhashtable.h b/include/linux/rhashtable.h
index fd82584..5c132d3 100644
--- a/include/linux/rhashtable.h
+++ b/include/linux/rhashtable.h
@@ -1,7 +1,7 @@
 /*
  * Resizable, Scalable, Concurrent Hash Table
  *
- * Copyright (c) 2015 Herbert Xu <herbert-lOAM2aK0SrRLBo1qDEOMRrpzq4S04n8Q@public.gmane.org>
+ * Copyright (c) 2015-2016 Herbert Xu <herbert-lOAM2aK0SrRLBo1qDEOMRrpzq4S04n8Q@public.gmane.org>
  * Copyright (c) 2014-2015 Thomas Graf <tgraf-G/eBtMaohhA@public.gmane.org>
  * Copyright (c) 2008-2014 Patrick McHardy <kaber-dcUjhNyLwpNeoWH0uzbU5w@public.gmane.org>
  *
@@ -53,6 +53,11 @@ struct rhash_head {
 	struct rhash_head __rcu		*next;
 };
 
+struct rhlist_head {
+	struct rhash_head		rhead;
+	struct rhlist_head __rcu	*next;
+};
+
 /**
  * struct bucket_table - Table of hash buckets
  * @size: Number of hash buckets
@@ -137,6 +142,7 @@ struct rhashtable_params {
  * @key_len: Key length for hashfn
  * @elasticity: Maximum chain length before rehash
  * @p: Configuration parameters
+ * @rhlist: True if this is an rhltable
  * @run_work: Deferred worker to expand/shrink asynchronously
  * @mutex: Mutex to protect current/future table swapping
  * @lock: Spin lock to protect walker list
@@ -147,12 +153,21 @@ struct rhashtable {
 	unsigned int			key_len;
 	unsigned int			elasticity;
 	struct rhashtable_params	p;
+	bool				rhlist;
 	struct work_struct		run_work;
 	struct mutex                    mutex;
 	spinlock_t			lock;
 };
 
 /**
+ * struct rhltable - Hash table with duplicate objects in a list
+ * @ht: Underlying rhtable
+ */
+struct rhltable {
+	struct rhashtable ht;
+};
+
+/**
  * struct rhashtable_walker - Hash table walker
  * @list: List entry on list of walkers
  * @tbl: The table that we were walking over
@@ -163,9 +178,10 @@ struct rhashtable_walker {
 };
 
 /**
- * struct rhashtable_iter - Hash table iterator, fits into netlink cb
+ * struct rhashtable_iter - Hash table iterator
  * @ht: Table to iterate through
  * @p: Current pointer
+ * @list: Current hash list pointer
  * @walker: Associated rhashtable walker
  * @slot: Current slot
  * @skip: Number of entries to skip in slot
@@ -173,6 +189,7 @@ struct rhashtable_walker {
 struct rhashtable_iter {
 	struct rhashtable *ht;
 	struct rhash_head *p;
+	struct rhlist_head *list;
 	struct rhashtable_walker walker;
 	unsigned int slot;
 	unsigned int skip;
@@ -339,13 +356,11 @@ static inline int lockdep_rht_bucket_is_held(const struct bucket_table *tbl,
 
 int rhashtable_init(struct rhashtable *ht,
 		    const struct rhashtable_params *params);
+int rhltable_init(struct rhltable *hlt,
+		  const struct rhashtable_params *params);
 
-struct bucket_table *rhashtable_insert_slow(struct rhashtable *ht,
-					    const void *key,
-					    struct rhash_head *obj,
-					    struct bucket_table *old_tbl,
-					    void **data);
-int rhashtable_insert_rehash(struct rhashtable *ht, struct bucket_table *tbl);
+void *rhashtable_insert_slow(struct rhashtable *ht, const void *key,
+			     struct rhash_head *obj);
 
 void rhashtable_walk_enter(struct rhashtable *ht,
 			   struct rhashtable_iter *iter);
@@ -507,6 +522,31 @@ void rhashtable_destroy(struct rhashtable *ht);
 	rht_for_each_entry_rcu_continue(tpos, pos, (tbl)->buckets[hash],\
 					tbl, hash, member)
 
+/**
+ * rhl_for_each_rcu - iterate over rcu hash table list
+ * @pos:	the &struct rlist_head to use as a loop cursor.
+ * @list:	the head of the list
+ *
+ * This hash chain list-traversal primitive should be used on the
+ * list returned by rhltable_lookup.
+ */
+#define rhl_for_each_rcu(pos, list)					\
+	for (pos = list; pos; pos = rcu_dereference_raw(pos->next))
+
+/**
+ * rhl_for_each_entry_rcu - iterate over rcu hash table list of given type
+ * @tpos:	the type * to use as a loop cursor.
+ * @pos:	the &struct rlist_head to use as a loop cursor.
+ * @list:	the head of the list
+ * @member:	name of the &struct rlist_head within the hashable struct.
+ *
+ * This hash chain list-traversal primitive should be used on the
+ * list returned by rhltable_lookup.
+ */
+#define rhl_for_each_entry_rcu(tpos, pos, list, member)			\
+	for (pos = list; pos && rht_entry(tpos, pos, member);		\
+	     pos = rcu_dereference_raw(pos->next))
+
 static inline int rhashtable_compare(struct rhashtable_compare_arg *arg,
 				     const void *obj)
 {
@@ -516,18 +556,8 @@ static inline int rhashtable_compare(struct rhashtable_compare_arg *arg,
 	return memcmp(ptr + ht->p.key_offset, arg->key, ht->p.key_len);
 }
 
-/**
- * rhashtable_lookup_fast - search hash table, inlined version
- * @ht:		hash table
- * @key:	the pointer to the key
- * @params:	hash table parameters
- *
- * Computes the hash value for the key and traverses the bucket chain looking
- * for a entry with an identical key. The first matching entry is returned.
- *
- * Returns the first entry on which the compare function returned true.
- */
-static inline void *rhashtable_lookup_fast(
+/* Internal function, do not use. */
+static inline struct rhash_head *__rhashtable_lookup(
 	struct rhashtable *ht, const void *key,
 	const struct rhashtable_params params)
 {
@@ -539,8 +569,6 @@ static inline void *rhashtable_lookup_fast(
 	struct rhash_head *he;
 	unsigned int hash;
 
-	rcu_read_lock();
-
 	tbl = rht_dereference_rcu(ht->tbl, ht);
 restart:
 	hash = rht_key_hashfn(ht, tbl, key, params);
@@ -549,8 +577,7 @@ restart:
 		    params.obj_cmpfn(&arg, rht_obj(ht, he)) :
 		    rhashtable_compare(&arg, rht_obj(ht, he)))
 			continue;
-		rcu_read_unlock();
-		return rht_obj(ht, he);
+		return he;
 	}
 
 	/* Ensure we see any new tables. */
@@ -559,96 +586,165 @@ restart:
 	tbl = rht_dereference_rcu(tbl->future_tbl, ht);
 	if (unlikely(tbl))
 		goto restart;
-	rcu_read_unlock();
 
 	return NULL;
 }
 
+/**
+ * rhashtable_lookup - search hash table
+ * @ht:		hash table
+ * @key:	the pointer to the key
+ * @params:	hash table parameters
+ *
+ * Computes the hash value for the key and traverses the bucket chain looking
+ * for a entry with an identical key. The first matching entry is returned.
+ *
+ * This must only be called under the RCU read lock.
+ *
+ * Returns the first entry on which the compare function returned true.
+ */
+static inline void *rhashtable_lookup(
+	struct rhashtable *ht, const void *key,
+	const struct rhashtable_params params)
+{
+	struct rhash_head *he = __rhashtable_lookup(ht, key, params);
+
+	return he ? rht_obj(ht, he) : NULL;
+}
+
+/**
+ * rhashtable_lookup_fast - search hash table, without RCU read lock
+ * @ht:		hash table
+ * @key:	the pointer to the key
+ * @params:	hash table parameters
+ *
+ * Computes the hash value for the key and traverses the bucket chain looking
+ * for a entry with an identical key. The first matching entry is returned.
+ *
+ * Only use this function when you have other mechanisms guaranteeing
+ * that the object won't go away after the RCU read lock is released.
+ *
+ * Returns the first entry on which the compare function returned true.
+ */
+static inline void *rhashtable_lookup_fast(
+	struct rhashtable *ht, const void *key,
+	const struct rhashtable_params params)
+{
+	void *obj;
+
+	rcu_read_lock();
+	obj = rhashtable_lookup(ht, key, params);
+	rcu_read_unlock();
+
+	return obj;
+}
+
+/**
+ * rhltable_lookup - search hash list table
+ * @hlt:	hash table
+ * @key:	the pointer to the key
+ * @params:	hash table parameters
+ *
+ * Computes the hash value for the key and traverses the bucket chain looking
+ * for a entry with an identical key.  All matching entries are returned
+ * in a list.
+ *
+ * This must only be called under the RCU read lock.
+ *
+ * Returns the list of entries that match the given key.
+ */
+static inline struct rhlist_head *rhltable_lookup(
+	struct rhltable *hlt, const void *key,
+	const struct rhashtable_params params)
+{
+	struct rhash_head *he = __rhashtable_lookup(&hlt->ht, key, params);
+
+	return he ? container_of(he, struct rhlist_head, rhead) : NULL;
+}
+
 /* Internal function, please use rhashtable_insert_fast() instead. This
  * function returns the existing element already in hashes in there is a clash,
  * otherwise it returns an error via ERR_PTR().
  */
 static inline void *__rhashtable_insert_fast(
 	struct rhashtable *ht, const void *key, struct rhash_head *obj,
-	const struct rhashtable_params params)
+	const struct rhashtable_params params, bool rhlist)
 {
 	struct rhashtable_compare_arg arg = {
 		.ht = ht,
 		.key = key,
 	};
-	struct bucket_table *tbl, *new_tbl;
+	struct rhash_head __rcu **pprev;
+	struct bucket_table *tbl;
 	struct rhash_head *head;
 	spinlock_t *lock;
-	unsigned int elasticity;
 	unsigned int hash;
-	void *data = NULL;
-	int err;
+	int elasticity;
+	void *data;
 
-restart:
 	rcu_read_lock();
 
 	tbl = rht_dereference_rcu(ht->tbl, ht);
+	hash = rht_head_hashfn(ht, tbl, obj, params);
+	lock = rht_bucket_lock(tbl, hash);
+	spin_lock_bh(lock);
 
-	/* All insertions must grab the oldest table containing
-	 * the hashed bucket that is yet to be rehashed.
-	 */
-	for (;;) {
-		hash = rht_head_hashfn(ht, tbl, obj, params);
-		lock = rht_bucket_lock(tbl, hash);
-		spin_lock_bh(lock);
-
-		if (tbl->rehash <= hash)
-			break;
-
+	if (unlikely(rht_dereference_bucket(tbl->future_tbl, tbl, hash))) {
+slow_path:
 		spin_unlock_bh(lock);
-		tbl = rht_dereference_rcu(tbl->future_tbl, ht);
+		rcu_read_unlock();
+		return rhashtable_insert_slow(ht, key, obj);
 	}
 
-	new_tbl = rht_dereference_rcu(tbl->future_tbl, ht);
-	if (unlikely(new_tbl)) {
-		tbl = rhashtable_insert_slow(ht, key, obj, new_tbl, &data);
-		if (!IS_ERR_OR_NULL(tbl))
-			goto slow_path;
+	elasticity = ht->elasticity;
+	pprev = &tbl->buckets[hash];
+	rht_for_each(head, tbl, hash) {
+		struct rhlist_head *plist;
+		struct rhlist_head *list;
+
+		elasticity--;
+		if (!key ||
+		    (params.obj_cmpfn ?
+		     params.obj_cmpfn(&arg, rht_obj(ht, head)) :
+		     rhashtable_compare(&arg, rht_obj(ht, head))))
+			continue;
+
+		data = rht_obj(ht, head);
 
-		err = PTR_ERR(tbl);
-		if (err == -EEXIST)
-			err = 0;
+		if (!rhlist)
+			goto out;
 
-		goto out;
-	}
 
-	err = -E2BIG;
-	if (unlikely(rht_grow_above_max(ht, tbl)))
-		goto out;
+		list = container_of(obj, struct rhlist_head, rhead);
+		plist = container_of(head, struct rhlist_head, rhead);
 
-	if (unlikely(rht_grow_above_100(ht, tbl))) {
-slow_path:
-		spin_unlock_bh(lock);
-		err = rhashtable_insert_rehash(ht, tbl);
-		rcu_read_unlock();
-		if (err)
-			return ERR_PTR(err);
+		RCU_INIT_POINTER(list->next, plist);
+		head = rht_dereference_bucket(head->next, tbl, hash);
+		RCU_INIT_POINTER(list->rhead.next, head);
+		rcu_assign_pointer(*pprev, obj);
 
-		goto restart;
+		goto good;
 	}
 
-	err = 0;
-	elasticity = ht->elasticity;
-	rht_for_each(head, tbl, hash) {
-		if (key &&
-		    unlikely(!(params.obj_cmpfn ?
-			       params.obj_cmpfn(&arg, rht_obj(ht, head)) :
-			       rhashtable_compare(&arg, rht_obj(ht, head))))) {
-			data = rht_obj(ht, head);
-			goto out;
-		}
-		if (!--elasticity)
-			goto slow_path;
-	}
+	if (elasticity <= 0)
+		goto slow_path;
+
+	data = ERR_PTR(-E2BIG);
+	if (unlikely(rht_grow_above_max(ht, tbl)))
+		goto out;
+
+	if (unlikely(rht_grow_above_100(ht, tbl)))
+		goto slow_path;
 
 	head = rht_dereference_bucket(tbl->buckets[hash], tbl, hash);
 
 	RCU_INIT_POINTER(obj->next, head);
+	if (rhlist) {
+		struct rhlist_head *list;
+
+		list = container_of(obj, struct rhlist_head, rhead);
+		RCU_INIT_POINTER(list->next, NULL);
+	}
 
 	rcu_assign_pointer(tbl->buckets[hash], obj);
 
@@ -656,11 +752,14 @@ slow_path:
 	if (rht_grow_above_75(ht, tbl))
 		schedule_work(&ht->run_work);
 
+good:
+	data = NULL;
+
 out:
 	spin_unlock_bh(lock);
 	rcu_read_unlock();
 
-	return err ? ERR_PTR(err) : data;
+	return data;
 }
 
 /**
@@ -685,7 +784,7 @@ static inline int rhashtable_insert_fast(
 {
 	void *ret;
 
-	ret = __rhashtable_insert_fast(ht, NULL, obj, params);
+	ret = __rhashtable_insert_fast(ht, NULL, obj, params, false);
 	if (IS_ERR(ret))
 		return PTR_ERR(ret);
 
@@ -693,6 +792,58 @@ static inline int rhashtable_insert_fast(
 }
 
 /**
+ * rhltable_insert_key - insert object into hash list table
+ * @hlt:	hash list table
+ * @key:	the pointer to the key
+ * @list:	pointer to hash list head inside object
+ * @params:	hash table parameters
+ *
+ * Will take a per bucket spinlock to protect against mutual mutations
+ * on the same bucket. Multiple insertions may occur in parallel unless
+ * they map to the same bucket lock.
+ *
+ * It is safe to call this function from atomic context.
+ *
+ * Will trigger an automatic deferred table resizing if the size grows
+ * beyond the watermark indicated by grow_decision() which can be passed
+ * to rhashtable_init().
+ */
+static inline int rhltable_insert_key(
+	struct rhltable *hlt, const void *key, struct rhlist_head *list,
+	const struct rhashtable_params params)
+{
+	return PTR_ERR(__rhashtable_insert_fast(&hlt->ht, key, &list->rhead,
+						params, true));
+}
+
+/**
+ * rhltable_insert - insert object into hash list table
+ * @hlt:	hash list table
+ * @list:	pointer to hash list head inside object
+ * @params:	hash table parameters
+ *
+ * Will take a per bucket spinlock to protect against mutual mutations
+ * on the same bucket. Multiple insertions may occur in parallel unless
+ * they map to the same bucket lock.
+ *
+ * It is safe to call this function from atomic context.
+ *
+ * Will trigger an automatic deferred table resizing if the size grows
+ * beyond the watermark indicated by grow_decision() which can be passed
+ * to rhashtable_init().
+ */
+static inline int rhltable_insert(
+	struct rhltable *hlt, struct rhlist_head *list,
+	const struct rhashtable_params params)
+{
+	const char *key = rht_obj(&hlt->ht, &list->rhead);
+
+	key += params.key_offset;
+
+	return rhltable_insert_key(hlt, key, list, params);
+}
+
+/**
  * rhashtable_lookup_insert_fast - lookup and insert object into hash table
  * @ht:		hash table
  * @obj:	pointer to hash head inside object
@@ -722,7 +873,8 @@ static inline int rhashtable_lookup_insert_fast(
 
 	BUG_ON(ht->p.obj_hashfn);
 
-	ret = __rhashtable_insert_fast(ht, key + ht->p.key_offset, obj, params);
+	ret = __rhashtable_insert_fast(ht, key + ht->p.key_offset, obj, params,
+				       false);
 	if (IS_ERR(ret))
 		return PTR_ERR(ret);
 
@@ -759,7 +911,7 @@ static inline int rhashtable_lookup_insert_key(
 
 	BUG_ON(!ht->p.obj_hashfn || !key);
 
-	ret = __rhashtable_insert_fast(ht, key, obj, params);
+	ret = __rhashtable_insert_fast(ht, key, obj, params, false);
 	if (IS_ERR(ret))
 		return PTR_ERR(ret);
 
@@ -783,13 +935,14 @@ static inline void *rhashtable_lookup_get_insert_key(
 {
 	BUG_ON(!ht->p.obj_hashfn || !key);
 
-	return __rhashtable_insert_fast(ht, key, obj, params);
+	return __rhashtable_insert_fast(ht, key, obj, params, false);
 }
 
 /* Internal function, please use rhashtable_remove_fast() instead */
-static inline int __rhashtable_remove_fast(
+static inline int __rhashtable_remove_fast_one(
 	struct rhashtable *ht, struct bucket_table *tbl,
-	struct rhash_head *obj, const struct rhashtable_params params)
+	struct rhash_head *obj, const struct rhashtable_params params,
+	bool rhlist)
 {
 	struct rhash_head __rcu **pprev;
 	struct rhash_head *he;
@@ -804,39 +957,66 @@ static inline int __rhashtable_remove_fast(
 
 	pprev = &tbl->buckets[hash];
 	rht_for_each(he, tbl, hash) {
+		struct rhlist_head *list;
+
+		list = container_of(he, struct rhlist_head, rhead);
+
 		if (he != obj) {
+			struct rhlist_head __rcu **lpprev;
+
 			pprev = &he->next;
-			continue;
+
+			if (!rhlist)
+				continue;
+
+			do {
+				lpprev = &list->next;
+				list = rht_dereference_bucket(list->next,
+							      tbl, hash);
+			} while (list && obj != &list->rhead);
+
+			if (!list)
+				continue;
+
+			list = rht_dereference_bucket(list->next, tbl, hash);
+			RCU_INIT_POINTER(*lpprev, list);
+			err = 0;
+			break;
 		}
 
-		rcu_assign_pointer(*pprev, obj->next);
-		err = 0;
+		obj = rht_dereference_bucket(obj->next, tbl, hash);
+		err = 1;
+
+		if (rhlist) {
+			list = rht_dereference_bucket(list->next, tbl, hash);
+			if (list) {
+				RCU_INIT_POINTER(list->rhead.next, obj);
+				obj = &list->rhead;
+				err = 0;
+			}
+		}
+
+		rcu_assign_pointer(*pprev, obj);
 		break;
 	}
 
 	spin_unlock_bh(lock);
 
+	if (err > 0) {
+		atomic_dec(&ht->nelems);
+		if (unlikely(ht->p.automatic_shrinking &&
+			     rht_shrink_below_30(ht, tbl)))
+			schedule_work(&ht->run_work);
+		err = 0;
+	}
+
 	return err;
 }
 
-/**
- * rhashtable_remove_fast - remove object from hash table
- * @ht:		hash table
- * @obj:	pointer to hash head inside object
- * @params:	hash table parameters
- *
- * Since the hash chain is single linked, the removal operation needs to
- * walk the bucket chain upon removal. The removal operation is thus
- * considerable slow if the hash table is not correctly sized.
- *
- * Will automatically shrink the table via rhashtable_expand() if the
- * shrink_decision function specified at rhashtable_init() returns true.
- *
- * Returns zero on success, -ENOENT if the entry could not be found.
- */
-static inline int rhashtable_remove_fast(
+/* Internal function, please use rhashtable_remove_fast() instead */
+static inline int __rhashtable_remove_fast(
 	struct rhashtable *ht, struct rhash_head *obj,
-	const struct rhashtable_params params)
+	const struct rhashtable_params params, bool rhlist)
 {
 	struct bucket_table *tbl;
 	int err;
@@ -850,24 +1030,60 @@ static inline int rhashtable_remove_fast(
 	 * visible then that guarantees the entry to still be in
 	 * the old tbl if it exists.
 	 */
-	while ((err = __rhashtable_remove_fast(ht, tbl, obj, params)) &&
+	while ((err = __rhashtable_remove_fast_one(ht, tbl, obj, params,
+						   rhlist)) &&
 	       (tbl = rht_dereference_rcu(tbl->future_tbl, ht)))
 		;
 
-	if (err)
-		goto out;
-
-	atomic_dec(&ht->nelems);
-	if (unlikely(ht->p.automatic_shrinking &&
-		     rht_shrink_below_30(ht, tbl)))
-		schedule_work(&ht->run_work);
-
-out:
 	rcu_read_unlock();
 
 	return err;
 }
 
+/**
+ * rhashtable_remove_fast - remove object from hash table
+ * @ht:		hash table
+ * @obj:	pointer to hash head inside object
+ * @params:	hash table parameters
+ *
+ * Since the hash chain is single linked, the removal operation needs to
+ * walk the bucket chain upon removal. The removal operation is thus
+ * considerable slow if the hash table is not correctly sized.
+ *
+ * Will automatically shrink the table via rhashtable_expand() if the
+ * shrink_decision function specified at rhashtable_init() returns true.
+ *
+ * Returns zero on success, -ENOENT if the entry could not be found.
+ */
+static inline int rhashtable_remove_fast(
+	struct rhashtable *ht, struct rhash_head *obj,
+	const struct rhashtable_params params)
+{
+	return __rhashtable_remove_fast(ht, obj, params, false);
+}
+
+/**
+ * rhltable_remove - remove object from hash list table
+ * @hlt:	hash list table
+ * @list:	pointer to hash list head inside object
+ * @params:	hash table parameters
+ *
+ * Since the hash chain is single linked, the removal operation needs to
+ * walk the bucket chain upon removal. The removal operation is thus
+ * considerable slow if the hash table is not correctly sized.
+ *
+ * Will automatically shrink the table via rhashtable_expand() if the
+ * shrink_decision function specified at rhashtable_init() returns true.
+ *
+ * Returns zero on success, -ENOENT if the entry could not be found.
+ */
+static inline int rhltable_remove(
+	struct rhltable *hlt, struct rhlist_head *list,
+	const struct rhashtable_params params)
+{
+	return __rhashtable_remove_fast(&hlt->ht, &list->rhead, params, true);
+}
+
 /* Internal function, please use rhashtable_replace_fast() instead */
 static inline int __rhashtable_replace_fast(
 	struct rhashtable *ht, struct bucket_table *tbl,
@@ -958,4 +1174,51 @@ static inline int rhashtable_walk_init(struct rhashtable *ht,
 	return 0;
 }
 
+/**
+ * rhltable_walk_enter - Initialise an iterator
+ * @hlt:	Table to walk over
+ * @iter:	Hash table Iterator
+ *
+ * This function prepares a hash table walk.
+ *
+ * Note that if you restart a walk after rhashtable_walk_stop you
+ * may see the same object twice.  Also, you may miss objects if
+ * there are removals in between rhashtable_walk_stop and the next
+ * call to rhashtable_walk_start.
+ *
+ * For a completely stable walk you should construct your own data
+ * structure outside the hash table.
+ *
+ * This function may sleep so you must not call it from interrupt
+ * context or with spin locks held.
+ *
+ * You must call rhashtable_walk_exit after this function returns.
+ */
+static inline void rhltable_walk_enter(struct rhltable *hlt,
+				       struct rhashtable_iter *iter)
+{
+	return rhashtable_walk_enter(&hlt->ht, iter);
+}
+
+/**
+ * rhltable_free_and_destroy - free elements and destroy hash list table
+ * @hlt:	the hash list table to destroy
+ * @free_fn:	callback to release resources of element
+ * @arg:	pointer passed to free_fn
+ *
+ * See documentation for rhashtable_free_and_destroy.
+ */
+static inline void rhltable_free_and_destroy(struct rhltable *hlt,
+					     void (*free_fn)(void *ptr,
+							     void *arg),
+					     void *arg)
+{
+	return rhashtable_free_and_destroy(&hlt->ht, free_fn, arg);
+}
+
+static inline void rhltable_destroy(struct rhltable *hlt)
+{
+	return rhltable_free_and_destroy(hlt, NULL, NULL);
+}
+
 #endif /* _LINUX_RHASHTABLE_H */
diff --git a/lib/rhashtable.c b/lib/rhashtable.c
index 06c2872..32d0ad0 100644
--- a/lib/rhashtable.c
+++ b/lib/rhashtable.c
@@ -378,22 +378,8 @@ static void rht_deferred_worker(struct work_struct *work)
 		schedule_work(&ht->run_work);
 }
 
-static bool rhashtable_check_elasticity(struct rhashtable *ht,
-					struct bucket_table *tbl,
-					unsigned int hash)
-{
-	unsigned int elasticity = ht->elasticity;
-	struct rhash_head *head;
-
-	rht_for_each(head, tbl, hash)
-		if (!--elasticity)
-			return true;
-
-	return false;
-}
-
-int rhashtable_insert_rehash(struct rhashtable *ht,
-			     struct bucket_table *tbl)
+static int rhashtable_insert_rehash(struct rhashtable *ht,
+				    struct bucket_table *tbl)
 {
 	struct bucket_table *old_tbl;
 	struct bucket_table *new_tbl;
@@ -439,57 +425,165 @@ fail:
 
 	return err;
 }
-EXPORT_SYMBOL_GPL(rhashtable_insert_rehash);
 
-struct bucket_table *rhashtable_insert_slow(struct rhashtable *ht,
-					    const void *key,
-					    struct rhash_head *obj,
-					    struct bucket_table *tbl,
-					    void **data)
+static void *rhashtable_lookup_one(struct rhashtable *ht,
+				   struct bucket_table *tbl, unsigned int hash,
+				   const void *key, struct rhash_head *obj)
 {
+	struct rhashtable_compare_arg arg = {
+		.ht = ht,
+		.key = key,
+	};
+	struct rhash_head __rcu **pprev;
 	struct rhash_head *head;
-	unsigned int hash;
-	int err;
+	int elasticity;
 
-	tbl = rhashtable_last_table(ht, tbl);
-	hash = head_hashfn(ht, tbl, obj);
-	spin_lock_nested(rht_bucket_lock(tbl, hash), SINGLE_DEPTH_NESTING);
-
-	err = -EEXIST;
-	if (key) {
-		*data = rhashtable_lookup_fast(ht, key, ht->p);
-		if (*data)
-			goto exit;
+	elasticity = ht->elasticity;
+	pprev = &tbl->buckets[hash];
+	rht_for_each(head, tbl, hash) {
+		struct rhlist_head *list;
+		struct rhlist_head *plist;
+
+		elasticity--;
+		if (!key ||
+		    (ht->p.obj_cmpfn ?
+		     ht->p.obj_cmpfn(&arg, rht_obj(ht, head)) :
+		     rhashtable_compare(&arg, rht_obj(ht, head))))
+			continue;
+
+		if (!ht->rhlist)
+			return rht_obj(ht, head);
+
+		list = container_of(obj, struct rhlist_head, rhead);
+		plist = container_of(head, struct rhlist_head, rhead);
+
+		RCU_INIT_POINTER(list->next, plist);
+		head = rht_dereference_bucket(head->next, tbl, hash);
+		RCU_INIT_POINTER(list->rhead.next, head);
+		rcu_assign_pointer(*pprev, obj);
+
+		return NULL;
 	}
 
-	err = -E2BIG;
-	if (unlikely(rht_grow_above_max(ht, tbl)))
-		goto exit;
+	if (elasticity <= 0)
+		return ERR_PTR(-EAGAIN);
+
+	return ERR_PTR(-ENOENT);
+}
+
+static struct bucket_table *rhashtable_insert_one(struct rhashtable *ht,
+						  struct bucket_table *tbl,
+						  unsigned int hash,
+						  struct rhash_head *obj,
+						  void *data)
+{
+	struct bucket_table *new_tbl;
+	struct rhash_head *head;
+
+	if (!IS_ERR_OR_NULL(data))
+		return ERR_PTR(-EEXIST);
 
-	err = -EAGAIN;
-	if (rhashtable_check_elasticity(ht, tbl, hash) ||
-	    rht_grow_above_100(ht, tbl))
-		goto exit;
+	if (PTR_ERR(data) != -EAGAIN && PTR_ERR(data) != -ENOENT)
+		return ERR_CAST(data);
 
-	err = 0;
+	new_tbl = rcu_dereference(tbl->future_tbl);
+	if (new_tbl)
+		return new_tbl;
+
+	if (PTR_ERR(data) != -ENOENT)
+		return ERR_CAST(data);
+
+	if (unlikely(rht_grow_above_max(ht, tbl)))
+		return ERR_PTR(-E2BIG);
+
+	if (unlikely(rht_grow_above_100(ht, tbl)))
+		return ERR_PTR(-EAGAIN);
 
 	head = rht_dereference_bucket(tbl->buckets[hash], tbl, hash);
 
 	RCU_INIT_POINTER(obj->next, head);
+	if (ht->rhlist) {
+		struct rhlist_head *list;
+
+		list = container_of(obj, struct rhlist_head, rhead);
+		RCU_INIT_POINTER(list->next, NULL);
+	}
 
 	rcu_assign_pointer(tbl->buckets[hash], obj);
 
 	atomic_inc(&ht->nelems);
+	if (rht_grow_above_75(ht, tbl))
+		schedule_work(&ht->run_work);
 
-exit:
-	spin_unlock(rht_bucket_lock(tbl, hash));
+	return NULL;
+}
 
-	if (err == 0)
-		return NULL;
-	else if (err == -EAGAIN)
-		return tbl;
-	else
-		return ERR_PTR(err);
+static void *rhashtable_try_insert(struct rhashtable *ht, const void *key,
+				   struct rhash_head *obj)
+{
+	struct bucket_table *new_tbl;
+	struct bucket_table *tbl;
+	unsigned int hash;
+	spinlock_t *lock;
+	void *data;
+
+	tbl = rcu_dereference(ht->tbl);
+
+	/* All insertions must grab the oldest table containing
+	 * the hashed bucket that is yet to be rehashed.
+	 */
+	for (;;) {
+		hash = rht_head_hashfn(ht, tbl, obj, ht->p);
+		lock = rht_bucket_lock(tbl, hash);
+		spin_lock_bh(lock);
+
+		if (tbl->rehash <= hash)
+			break;
+
+		spin_unlock_bh(lock);
+		tbl = rcu_dereference(tbl->future_tbl);
+	}
+
+	data = rhashtable_lookup_one(ht, tbl, hash, key, obj);
+	new_tbl = rhashtable_insert_one(ht, tbl, hash, obj, data);
+	if (PTR_ERR(new_tbl) != -EEXIST)
+		data = ERR_CAST(new_tbl);
+
+	while (!IS_ERR_OR_NULL(new_tbl)) {
+		tbl = new_tbl;
+		hash = rht_head_hashfn(ht, tbl, obj, ht->p);
+		spin_lock_nested(rht_bucket_lock(tbl, hash),
+				 SINGLE_DEPTH_NESTING);
+
+		data = rhashtable_lookup_one(ht, tbl, hash, key, obj);
+		new_tbl = rhashtable_insert_one(ht, tbl, hash, obj, data);
+		if (PTR_ERR(new_tbl) != -EEXIST)
+			data = ERR_CAST(new_tbl);
+
+		spin_unlock(rht_bucket_lock(tbl, hash));
+	}
+
+	spin_unlock_bh(lock);
+
+	if (PTR_ERR(data) == -EAGAIN)
+		data = ERR_PTR(rhashtable_insert_rehash(ht, tbl) ?:
+			       -EAGAIN);
+
+	return data;
+}
+
+void *rhashtable_insert_slow(struct rhashtable *ht, const void *key,
+			     struct rhash_head *obj)
+{
+	void *data;
+
+	do {
+		rcu_read_lock();
+		data = rhashtable_try_insert(ht, key, obj);
+		rcu_read_unlock();
+	} while (PTR_ERR(data) == -EAGAIN);
+
+	return data;
 }
 EXPORT_SYMBOL_GPL(rhashtable_insert_slow);
 
@@ -593,11 +687,16 @@ EXPORT_SYMBOL_GPL(rhashtable_walk_start);
 void *rhashtable_walk_next(struct rhashtable_iter *iter)
 {
 	struct bucket_table *tbl = iter->walker.tbl;
+	struct rhlist_head *list = iter->list;
 	struct rhashtable *ht = iter->ht;
 	struct rhash_head *p = iter->p;
+	bool rhlist = ht->rhlist;
 
 	if (p) {
-		p = rht_dereference_bucket_rcu(p->next, tbl, iter->slot);
+		if (!rhlist || !(list = rcu_dereference(list->next))) {
+			p = rcu_dereference(p->next);
+			list = container_of(p, struct rhlist_head, rhead);
+		}
 		goto next;
 	}
 
@@ -605,6 +704,18 @@ void *rhashtable_walk_next(struct rhashtable_iter *iter)
 		int skip = iter->skip;
 
 		rht_for_each_rcu(p, tbl, iter->slot) {
+			if (rhlist) {
+				list = container_of(p, struct rhlist_head,
+						    rhead);
+				do {
+					if (!skip)
+						goto next;
+					skip--;
+					list = rcu_dereference(list->next);
+				} while (list);
+
+				continue;
+			}
 			if (!skip)
 				break;
 			skip--;
@@ -614,7 +725,8 @@ next:
 		if (!rht_is_a_nulls(p)) {
 			iter->skip++;
 			iter->p = p;
-			return rht_obj(ht, p);
+			iter->list = list;
+			return rht_obj(ht, rhlist ? &list->rhead : p);
 		}
 
 		iter->skip = 0;
@@ -803,6 +915,48 @@ int rhashtable_init(struct rhashtable *ht,
 EXPORT_SYMBOL_GPL(rhashtable_init);
 
 /**
+ * rhltable_init - initialize a new hash list table
+ * @hlt:	hash list table to be initialized
+ * @params:	configuration parameters
+ *
+ * Initializes a new hash list table.
+ *
+ * See documentation for rhashtable_init.
+ */
+int rhltable_init(struct rhltable *hlt, const struct rhashtable_params *params)
+{
+	int err;
+
+	/* No rhlist NULLs marking for now. */
+	if (params->nulls_base)
+		return -EINVAL;
+
+	err = rhashtable_init(&hlt->ht, params);
+	hlt->ht.rhlist = true;
+	return err;
+}
+EXPORT_SYMBOL_GPL(rhltable_init);
+
+static void rhashtable_free_one(struct rhashtable *ht, struct rhash_head *obj,
+				void (*free_fn)(void *ptr, void *arg),
+				void *arg)
+{
+	struct rhlist_head *list;
+
+	if (!ht->rhlist) {
+		free_fn(rht_obj(ht, obj), arg);
+		return;
+	}
+
+	list = container_of(obj, struct rhlist_head, rhead);
+	do {
+		obj = &list->rhead;
+		list = rht_dereference(list->next, ht);
+		free_fn(rht_obj(ht, obj), arg);
+	} while (list);
+}
+
+/**
  * rhashtable_free_and_destroy - free elements and destroy hash table
  * @ht:		the hash table to destroy
  * @free_fn:	callback to release resources of element
@@ -839,7 +993,7 @@ void rhashtable_free_and_destroy(struct rhashtable *ht,
 			     pos = next,
 			     next = !rht_is_a_nulls(pos) ?
 					rht_dereference(pos->next, ht) : NULL)
-				free_fn(rht_obj(ht, pos), arg);
+				rhashtable_free_one(ht, pos, free_fn, arg);
 		}
 	}
 

[v3 PATCH 2/2] mac80211: Use rhltable instead of rhashtable

[Herbert Xu]

mac80211 currently uses rhashtable with insecure_elasticity set
to true.  The latter is because of duplicate objects.  What's
more, mac80211 walks the rhashtable chains by hand which is broken
as rhashtable may contain multiple tables due to resizing or
rehashing.

This patch fixes it by converting it to the newly added rhltable
interface which is designed for use with duplicate objects.

With rhltable a lookup returns a list of objects instead of a
single one.  This is then fed into the existing for_each_sta_info
macro.

This patch also deletes the sta_addr_hash function since rhashtable
defaults to jhash.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
---

 net/mac80211/ieee80211_i.h |    2 -
 net/mac80211/rx.c          |    7 +-----
 net/mac80211/sta_info.c    |   52 ++++++++++++++++++---------------------------
 net/mac80211/sta_info.h    |   19 ++++++----------
 net/mac80211/status.c      |    7 +-----
 5 files changed, 33 insertions(+), 54 deletions(-)

diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index f56d342..1a52cd4 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -1208,7 +1208,7 @@ struct ieee80211_local {
 	spinlock_t tim_lock;
 	unsigned long num_sta;
 	struct list_head sta_list;
-	struct rhashtable sta_hash;
+	struct rhltable sta_hash;
 	struct timer_list sta_cleanup;
 	int sta_generation;
 
diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index 9dce3b1..5e26dc6 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -3940,7 +3940,7 @@ static void __ieee80211_rx_handle_packet(struct ieee80211_hw *hw,
 	__le16 fc;
 	struct ieee80211_rx_data rx;
 	struct ieee80211_sub_if_data *prev;
-	struct rhash_head *tmp;
+	struct rhlist_head *tmp;
 	int err = 0;
 
 	fc = ((struct ieee80211_hdr *)skb->data)->frame_control;
@@ -3983,13 +3983,10 @@ static void __ieee80211_rx_handle_packet(struct ieee80211_hw *hw,
 		goto out;
 	} else if (ieee80211_is_data(fc)) {
 		struct sta_info *sta, *prev_sta;
-		const struct bucket_table *tbl;
 
 		prev_sta = NULL;
 
-		tbl = rht_dereference_rcu(local->sta_hash.tbl, &local->sta_hash);
-
-		for_each_sta_info(local, tbl, hdr->addr2, sta, tmp) {
+		for_each_sta_info(local, hdr->addr2, sta, tmp) {
 			if (!prev_sta) {
 				prev_sta = sta;
 				continue;
diff --git a/net/mac80211/sta_info.c b/net/mac80211/sta_info.c
index 19f14c9..198d0bd 100644
--- a/net/mac80211/sta_info.c
+++ b/net/mac80211/sta_info.c
@@ -67,12 +67,10 @@
 
 static const struct rhashtable_params sta_rht_params = {
 	.nelem_hint = 3, /* start small */
-	.insecure_elasticity = true, /* Disable chain-length checks. */
 	.automatic_shrinking = true,
 	.head_offset = offsetof(struct sta_info, hash_node),
 	.key_offset = offsetof(struct sta_info, addr),
 	.key_len = ETH_ALEN,
-	.hashfn = sta_addr_hash,
 	.max_size = CONFIG_MAC80211_STA_HASH_MAX_SIZE,
 };
 
@@ -80,8 +78,8 @@ static const struct rhashtable_params sta_rht_params = {
 static int sta_info_hash_del(struct ieee80211_local *local,
 			     struct sta_info *sta)
 {
-	return rhashtable_remove_fast(&local->sta_hash, &sta->hash_node,
-				      sta_rht_params);
+	return rhltable_remove(&local->sta_hash, &sta->hash_node,
+			       sta_rht_params);
 }
 
 static void __cleanup_single_sta(struct sta_info *sta)
@@ -157,19 +155,22 @@ static void cleanup_single_sta(struct sta_info *sta)
 	sta_info_free(local, sta);
 }
 
+struct rhlist_head *sta_info_hash_lookup(struct ieee80211_local *local,
+					 const u8 *addr)
+{
+	return rhltable_lookup(&local->sta_hash, addr, sta_rht_params);
+}
+
 /* protected by RCU */
 struct sta_info *sta_info_get(struct ieee80211_sub_if_data *sdata,
 			      const u8 *addr)
 {
 	struct ieee80211_local *local = sdata->local;
+	struct rhlist_head *tmp;
 	struct sta_info *sta;
-	struct rhash_head *tmp;
-	const struct bucket_table *tbl;
 
 	rcu_read_lock();
-	tbl = rht_dereference_rcu(local->sta_hash.tbl, &local->sta_hash);
-
-	for_each_sta_info(local, tbl, addr, sta, tmp) {
+	for_each_sta_info(local, addr, sta, tmp) {
 		if (sta->sdata == sdata) {
 			rcu_read_unlock();
 			/* this is safe as the caller must already hold
@@ -190,14 +191,11 @@ struct sta_info *sta_info_get_bss(struct ieee80211_sub_if_data *sdata,
 				  const u8 *addr)
 {
 	struct ieee80211_local *local = sdata->local;
+	struct rhlist_head *tmp;
 	struct sta_info *sta;
-	struct rhash_head *tmp;
-	const struct bucket_table *tbl;
 
 	rcu_read_lock();
-	tbl = rht_dereference_rcu(local->sta_hash.tbl, &local->sta_hash);
-
-	for_each_sta_info(local, tbl, addr, sta, tmp) {
+	for_each_sta_info(local, addr, sta, tmp) {
 		if (sta->sdata == sdata ||
 		    (sta->sdata->bss && sta->sdata->bss == sdata->bss)) {
 			rcu_read_unlock();
@@ -263,8 +261,8 @@ void sta_info_free(struct ieee80211_local *local, struct sta_info *sta)
 static int sta_info_hash_add(struct ieee80211_local *local,
 			     struct sta_info *sta)
 {
-	return rhashtable_insert_fast(&local->sta_hash, &sta->hash_node,
-				      sta_rht_params);
+	return rhltable_insert(&local->sta_hash, &sta->hash_node,
+			       sta_rht_params);
 }
 
 static void sta_deliver_ps_frames(struct work_struct *wk)
@@ -450,9 +448,9 @@ static int sta_info_insert_check(struct sta_info *sta)
 		    is_multicast_ether_addr(sta->sta.addr)))
 		return -EINVAL;
 
-	/* Strictly speaking this isn't necessary as we hold the mutex, but
-	 * the rhashtable code can't really deal with that distinction. We
-	 * do require the mutex for correctness though.
+	/* The RCU read lock is required by rhashtable due to
+	 * asynchronous resize/rehash.  We also require the mutex
+	 * for correctness.
 	 */
 	rcu_read_lock();
 	lockdep_assert_held(&sdata->local->sta_mtx);
@@ -1040,16 +1038,11 @@ static void sta_info_cleanup(unsigned long data)
 		  round_jiffies(jiffies + STA_INFO_CLEANUP_INTERVAL));
 }
 
-u32 sta_addr_hash(const void *key, u32 length, u32 seed)
-{
-	return jhash(key, ETH_ALEN, seed);
-}
-
 int sta_info_init(struct ieee80211_local *local)
 {
 	int err;
 
-	err = rhashtable_init(&local->sta_hash, &sta_rht_params);
+	err = rhltable_init(&local->sta_hash, &sta_rht_params);
 	if (err)
 		return err;
 
@@ -1065,7 +1058,7 @@ int sta_info_init(struct ieee80211_local *local)
 void sta_info_stop(struct ieee80211_local *local)
 {
 	del_timer_sync(&local->sta_cleanup);
-	rhashtable_destroy(&local->sta_hash);
+	rhltable_destroy(&local->sta_hash);
 }
 
 
@@ -1135,17 +1128,14 @@ struct ieee80211_sta *ieee80211_find_sta_by_ifaddr(struct ieee80211_hw *hw,
 						   const u8 *localaddr)
 {
 	struct ieee80211_local *local = hw_to_local(hw);
+	struct rhlist_head *tmp;
 	struct sta_info *sta;
-	struct rhash_head *tmp;
-	const struct bucket_table *tbl;
-
-	tbl = rht_dereference_rcu(local->sta_hash.tbl, &local->sta_hash);
 
 	/*
 	 * Just return a random station if localaddr is NULL
 	 * ... first in list.
 	 */
-	for_each_sta_info(local, tbl, addr, sta, tmp) {
+	for_each_sta_info(local, addr, sta, tmp) {
 		if (localaddr &&
 		    !ether_addr_equal(sta->sdata->vif.addr, localaddr))
 			continue;
diff --git a/net/mac80211/sta_info.h b/net/mac80211/sta_info.h
index 0556be3..d347ab5 100644
--- a/net/mac80211/sta_info.h
+++ b/net/mac80211/sta_info.h
@@ -452,7 +452,7 @@ struct sta_info {
 	/* General information, mostly static */
 	struct list_head list, free_list;
 	struct rcu_head rcu_head;
-	struct rhash_head hash_node;
+	struct rhlist_head hash_node;
 	u8 addr[ETH_ALEN];
 	struct ieee80211_local *local;
 	struct ieee80211_sub_if_data *sdata;
@@ -635,6 +635,9 @@ rcu_dereference_protected_tid_tx(struct sta_info *sta, int tid)
  */
 #define STA_INFO_CLEANUP_INTERVAL (10 * HZ)
 
+struct rhlist_head *sta_info_hash_lookup(struct ieee80211_local *local,
+					 const u8 *addr);
+
 /*
  * Get a STA info, must be under RCU read lock.
  */
@@ -644,17 +647,9 @@ struct sta_info *sta_info_get(struct ieee80211_sub_if_data *sdata,
 struct sta_info *sta_info_get_bss(struct ieee80211_sub_if_data *sdata,
 				  const u8 *addr);
 
-u32 sta_addr_hash(const void *key, u32 length, u32 seed);
-
-#define _sta_bucket_idx(_tbl, _a)					\
-	rht_bucket_index(_tbl, sta_addr_hash(_a, ETH_ALEN, (_tbl)->hash_rnd))
-
-#define for_each_sta_info(local, tbl, _addr, _sta, _tmp)		\
-	rht_for_each_entry_rcu(_sta, _tmp, tbl, 			\
-			       _sta_bucket_idx(tbl, _addr),		\
-			       hash_node)				\
-	/* compare address and run code only if it matches */		\
-	if (ether_addr_equal(_sta->addr, (_addr)))
+#define for_each_sta_info(local, _addr, _sta, _tmp)			\
+	rhl_for_each_entry_rcu(_sta, _tmp,				\
+			       sta_info_hash_lookup(local, _addr), hash_node)
 
 /*
  * Get STA info by index, BROKEN!
diff --git a/net/mac80211/status.c b/net/mac80211/status.c
index a2a6826..6361709 100644
--- a/net/mac80211/status.c
+++ b/net/mac80211/status.c
@@ -740,8 +740,8 @@ void ieee80211_tx_status(struct ieee80211_hw *hw, struct sk_buff *skb)
 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 	__le16 fc;
 	struct ieee80211_supported_band *sband;
+	struct rhlist_head *tmp;
 	struct sta_info *sta;
-	struct rhash_head *tmp;
 	int retry_count;
 	int rates_idx;
 	bool send_to_cooked;
@@ -749,7 +749,6 @@ void ieee80211_tx_status(struct ieee80211_hw *hw, struct sk_buff *skb)
 	struct ieee80211_bar *bar;
 	int shift = 0;
 	int tid = IEEE80211_NUM_TIDS;
-	const struct bucket_table *tbl;
 
 	rates_idx = ieee80211_tx_get_rates(hw, info, &retry_count);
 
@@ -758,9 +757,7 @@ void ieee80211_tx_status(struct ieee80211_hw *hw, struct sk_buff *skb)
 	sband = local->hw.wiphy->bands[info->band];
 	fc = hdr->frame_control;
 
-	tbl = rht_dereference_rcu(local->sta_hash.tbl, &local->sta_hash);
-
-	for_each_sta_info(local, tbl, hdr->addr1, sta, tmp) {
+	for_each_sta_info(local, hdr->addr1, sta, tmp) {
 		/* skip wrong virtual interface */
 		if (!ether_addr_equal(hdr->addr2, sta->sdata->vif.addr))
 			continue;

Re: [v3 PATCH 0/2] rhashtable: rhashtable with duplicate objects

[Johannes Berg]

On Mon, 2016-09-19 at 18:58 +0800, Herbert Xu wrote:
> v3 fixes a bug in the remove path that causes the element count
> to decrease when it shouldn't, leading to a gigantic hash table
> when it underflows.
> 
Ok, with the BUG_ON() thrown in, this works in the test that was
failing before. I'll run the entire suite again over lunch.

johannes

Re: [v3 PATCH 0/2] rhashtable: rhashtable with duplicate objects

[Johannes Berg]

On Mon, 2016-09-19 at 13:03 +0200, Johannes Berg wrote:
> On Mon, 2016-09-19 at 18:58 +0800, Herbert Xu wrote:
> > 
> > v3 fixes a bug in the remove path that causes the element count
> > to decrease when it shouldn't, leading to a gigantic hash table
> > when it underflows.
> > 
> Ok, with the BUG_ON() thrown in, this works in the test that was
> failing before. I'll run the entire suite again over lunch.
> 

Ok, the entire test suite passed (with the BUG_ON, but hey).

Dave, let me know what you want to do (or have done, as it may be).

Thanks,
johannes

Re: [v3 PATCH 0/2] rhashtable: rhashtable with duplicate objects

[Johannes Berg]

On Mon, 2016-09-19 at 13:03 +0200, Johannes Berg wrote:
> On Mon, 2016-09-19 at 18:58 +0800, Herbert Xu wrote:
> > 
> > v3 fixes a bug in the remove path that causes the element count
> > to decrease when it shouldn't, leading to a gigantic hash table
> > when it underflows.
> > 
> Ok, with the BUG_ON() thrown in, this works in the test that was
> failing before. I'll run the entire suite again over lunch.
> 

Ok, the entire test suite passed (with the BUG_ON, but hey).

Dave, let me know what you want to do (or have done, as it may be).

Thanks,
johannes

Re: [v3 PATCH 1/2] rhashtable: Add rhlist interface

[Thomas Graf]

On 09/19/16 at 07:00pm, Herbert Xu wrote:
> The insecure_elasticity setting is an ugly wart brought out by
> users who need to insert duplicate objects (that is, distinct
> objects with identical keys) into the same table.
> 
> In fact, those users have a much bigger problem.  Once those
> duplicate objects are inserted, they don't have an interface to
> find them (unless you count the walker interface which walks
> over the entire table).
> 
> Some users have resorted to doing a manual walk over the hash
> table which is of course broken because they don't handle the
> potential existence of multiple hash tables.  The result is that
> they will break sporadically when they encounter a hash table
> resize/rehash.
> 
> This patch provides a way out for those users, at the expense
> of an extra pointer per object.  Essentially each object is now
> a list of objects carrying the same key.  The hash table will
> only see the lists so nothing changes as far as rhashtable is
> concerned.
> 
> To use this new interface, you need to insert a struct rhlist_head
> into your objects instead of struct rhash_head.  While the hash
> table is unchanged, for type-safety you'll need to use struct
> rhltable instead of struct rhashtable.  All the existing interfaces
> have been duplicated for rhlist, including the hash table walker.
> 
> One missing feature is nulls marking because AFAIK the only potential
> user of it does not need duplicate objects.  Should anyone need
> this it shouldn't be too hard to add.
> 
> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

Nice, I like how this simplifies users! Is this suitable for
ILA as well?

Acked-by: Thomas Graf <tgraf@suug.ch>

Re: [v3 PATCH 1/2] rhashtable: Add rhlist interface

[Herbert Xu]

On Mon, Sep 19, 2016 at 11:16:21PM +0200, Thomas Graf wrote:
>
> Nice, I like how this simplifies users! Is this suitable for
> ILA as well?

Does it have duplicate objects and use inelastic_security? If so
then yes it should switch over to rhlist.

Cheers,
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

Re: [v3 PATCH 0/2] rhashtable: rhashtable with duplicate objects

[David Miller]

From: Johannes Berg <johannes@sipsolutions.net>
Date: Mon, 19 Sep 2016 13:32:12 +0200

> On Mon, 2016-09-19 at 13:03 +0200, Johannes Berg wrote:
>> On Mon, 2016-09-19 at 18:58 +0800, Herbert Xu wrote:
>> > 
>> > v3 fixes a bug in the remove path that causes the element count
>> > to decrease when it shouldn't, leading to a gigantic hash table
>> > when it underflows.
>> > 
>> Ok, with the BUG_ON() thrown in, this works in the test that was
>> failing before. I'll run the entire suite again over lunch.
>> 
> 
> Ok, the entire test suite passed (with the BUG_ON, but hey).
> 
> Dave, let me know what you want to do (or have done, as it may be).

I'll apply this directly to net-next and push it out after some
build testing.

Thanks guys.

Re: [v3 PATCH 0/2] rhashtable: rhashtable with duplicate objects

[David Miller]

From: Johannes Berg <johannes-cdvu00un1VgdHxzADdlk8Q@public.gmane.org>
Date: Mon, 19 Sep 2016 13:32:12 +0200

> On Mon, 2016-09-19 at 13:03 +0200, Johannes Berg wrote:
>> On Mon, 2016-09-19 at 18:58 +0800, Herbert Xu wrote:
>> > 
>> > v3 fixes a bug in the remove path that causes the element count
>> > to decrease when it shouldn't, leading to a gigantic hash table
>> > when it underflows.
>> > 
>> Ok, with the BUG_ON() thrown in, this works in the test that was
>> failing before. I'll run the entire suite again over lunch.
>> 
> 
> Ok, the entire test suite passed (with the BUG_ON, but hey).
> 
> Dave, let me know what you want to do (or have done, as it may be).

I'll apply this directly to net-next and push it out after some
build testing.

Thanks guys.