[PATCH for-next 0/5] RDMA/rxe: Fix rxe_alloc() bug

[PATCH for-next 0/5] RDMA/rxe: Fix rxe_alloc() bug

[Bob Pearson]

This short series of patches corrects a bug introduced and
then addresses several issues raised during discussion
of the bug and the proposed fix.

The first patch fixes a real bug but the other four are
stylistic and cleanup changes.

Signed-off-by: Bob Pearson <rpearson@hpe.com>
*** BLURB HERE ***

Bob Pearson (5):
  RDMA/rxe: Fix bug in rxe_alloc
  RDMA/rxe: Fix misleading comments and names
  RDMA/rxe: Remove RXE_POOL_ATOMIC
  RDMA/rxe: Remove calls to ib_device_try_get/put
  RDMA/rxe: Remove unneeded pool->flag

 drivers/infiniband/sw/rxe/rxe_mcast.c |  8 +--
 drivers/infiniband/sw/rxe/rxe_pool.c  | 90 ++++++++++-----------------
 drivers/infiniband/sw/rxe/rxe_pool.h  | 62 ++++++++----------
 3 files changed, 63 insertions(+), 97 deletions(-)

-- 
2.27.0

[PATCH for-next 1/5] RDMA/rxe: Fix bug in rxe_alloc

[Bob Pearson]

A recent patch which added an 'unlocked' version of rxe_alloc
introduced a bug causing kzalloc(..., GFP_KERNEL) to be called
while holding a spin lock. This patch corrects that error.

rxe_alloc_nl() should always be called while holding the pool->pool_lock
so the 2nd argument to kzalloc there should be GFP_ATOMIC.

rxe_alloc() prior to the change only locked the code around checking
that pool->state is RXE_POOL_STATE_VALID to avoid races between
working threads and a thread shutting down the rxe driver. This patch
reverts rxe_alloc() to this behavior so the lock is not held when
kzalloc() is called.

Reported-by: syzbot+ec2fd72374785d0e558e@syzkaller.appspotmail.com
Fixes: 3853c35e243d ("RDMA/rxe: Add unlocked versions of pool APIs")
Signed-off-by: Bob Pearson <rpearson@hpe.com>
---
 drivers/infiniband/sw/rxe/rxe_pool.c | 41 ++++++++++++++++++++++++----
 1 file changed, 35 insertions(+), 6 deletions(-)

diff --git a/drivers/infiniband/sw/rxe/rxe_pool.c b/drivers/infiniband/sw/rxe/rxe_pool.c
index d26730eec720..cfcd55175572 100644
--- a/drivers/infiniband/sw/rxe/rxe_pool.c
+++ b/drivers/infiniband/sw/rxe/rxe_pool.c
@@ -343,8 +343,6 @@ void *rxe_alloc_nl(struct rxe_pool *pool)
 	struct rxe_pool_entry *elem;
 	u8 *obj;
 
-	might_sleep_if(!(pool->flags & RXE_POOL_ATOMIC));
-
 	if (pool->state != RXE_POOL_STATE_VALID)
 		return NULL;
 
@@ -356,8 +354,7 @@ void *rxe_alloc_nl(struct rxe_pool *pool)
 	if (atomic_inc_return(&pool->num_elem) > pool->max_elem)
 		goto out_cnt;
 
-	obj = kzalloc(info->size, (pool->flags & RXE_POOL_ATOMIC) ?
-		      GFP_ATOMIC : GFP_KERNEL);
+	obj = kzalloc(info->size, GFP_ATOMIC);
 	if (!obj)
 		goto out_cnt;
 
@@ -378,14 +375,46 @@ void *rxe_alloc_nl(struct rxe_pool *pool)
 
 void *rxe_alloc(struct rxe_pool *pool)
 {
-	u8 *obj;
 	unsigned long flags;
+	struct rxe_type_info *info = &rxe_type_info[pool->type];
+	struct rxe_pool_entry *elem;
+	u8 *obj;
+
+	might_sleep_if(!(pool->flags & RXE_POOL_ATOMIC));
 
 	read_lock_irqsave(&pool->pool_lock, flags);
-	obj = rxe_alloc_nl(pool);
+	if (pool->state != RXE_POOL_STATE_VALID) {
+		read_unlock_irqrestore(&pool->pool_lock, flags);
+		return NULL;
+	}
+
+	kref_get(&pool->ref_cnt);
 	read_unlock_irqrestore(&pool->pool_lock, flags);
 
+	if (!ib_device_try_get(&pool->rxe->ib_dev))
+		goto out_put_pool;
+
+	if (atomic_inc_return(&pool->num_elem) > pool->max_elem)
+		goto out_cnt;
+
+	obj = kzalloc(info->size, (pool->flags & RXE_POOL_ATOMIC) ?
+		      GFP_ATOMIC : GFP_KERNEL);
+	if (!obj)
+		goto out_cnt;
+
+	elem = (struct rxe_pool_entry *)(obj + info->elem_offset);
+
+	elem->pool = pool;
+	kref_init(&elem->ref_cnt);
+
 	return obj;
+
+out_cnt:
+	atomic_dec(&pool->num_elem);
+	ib_device_put(&pool->rxe->ib_dev);
+out_put_pool:
+	rxe_pool_put(pool);
+	return NULL;
 }
 
 int __rxe_add_to_pool(struct rxe_pool *pool, struct rxe_pool_entry *elem)
-- 
2.27.0

[PATCH for-next 2/5] RDMA/rxe: Fix misleading comments and names

[Bob Pearson]

The names and comments of the 'unlocked' pool APIs are very
misleading and not what was intended. This patch replaces
'rxe_xxx_nl' with 'rxe_xxx__' with comments indicating that the
caller is expected to hold the rxe pool lock.

Reported-by: Hillf Danton <hdanton@sina.com>
Signed-off-by: Bob Pearson <rpearson@hpe.com>
---
 drivers/infiniband/sw/rxe/rxe_mcast.c |  8 ++--
 drivers/infiniband/sw/rxe/rxe_pool.c  | 22 +++++------
 drivers/infiniband/sw/rxe/rxe_pool.h  | 55 +++++++++++++--------------
 3 files changed, 42 insertions(+), 43 deletions(-)

diff --git a/drivers/infiniband/sw/rxe/rxe_mcast.c b/drivers/infiniband/sw/rxe/rxe_mcast.c
index 5be47ce7d319..b9f06f87866e 100644
--- a/drivers/infiniband/sw/rxe/rxe_mcast.c
+++ b/drivers/infiniband/sw/rxe/rxe_mcast.c
@@ -15,18 +15,18 @@ static struct rxe_mc_grp *create_grp(struct rxe_dev *rxe,
 	int err;
 	struct rxe_mc_grp *grp;
 
-	grp = rxe_alloc_nl(&rxe->mc_grp_pool);
+	grp = rxe_alloc__(&rxe->mc_grp_pool);
 	if (!grp)
 		return ERR_PTR(-ENOMEM);
 
 	INIT_LIST_HEAD(&grp->qp_list);
 	spin_lock_init(&grp->mcg_lock);
 	grp->rxe = rxe;
-	rxe_add_key_nl(grp, mgid);
+	rxe_add_key__(grp, mgid);
 
 	err = rxe_mcast_add(rxe, mgid);
 	if (unlikely(err)) {
-		rxe_drop_key_nl(grp);
+		rxe_drop_key__(grp);
 		rxe_drop_ref(grp);
 		return ERR_PTR(err);
 	}
@@ -47,7 +47,7 @@ int rxe_mcast_get_grp(struct rxe_dev *rxe, union ib_gid *mgid,
 
 	write_lock_irqsave(&pool->pool_lock, flags);
 
-	grp = rxe_pool_get_key_nl(pool, mgid);
+	grp = rxe_pool_get_key__(pool, mgid);
 	if (grp)
 		goto done;
 
diff --git a/drivers/infiniband/sw/rxe/rxe_pool.c b/drivers/infiniband/sw/rxe/rxe_pool.c
index cfcd55175572..80deec1e2924 100644
--- a/drivers/infiniband/sw/rxe/rxe_pool.c
+++ b/drivers/infiniband/sw/rxe/rxe_pool.c
@@ -266,7 +266,7 @@ static void insert_key(struct rxe_pool *pool, struct rxe_pool_entry *new)
 	return;
 }
 
-void __rxe_add_key_nl(struct rxe_pool_entry *elem, void *key)
+void __rxe_add_key__(struct rxe_pool_entry *elem, void *key)
 {
 	struct rxe_pool *pool = elem->pool;
 
@@ -280,11 +280,11 @@ void __rxe_add_key(struct rxe_pool_entry *elem, void *key)
 	unsigned long flags;
 
 	write_lock_irqsave(&pool->pool_lock, flags);
-	__rxe_add_key_nl(elem, key);
+	__rxe_add_key__(elem, key);
 	write_unlock_irqrestore(&pool->pool_lock, flags);
 }
 
-void __rxe_drop_key_nl(struct rxe_pool_entry *elem)
+void __rxe_drop_key__(struct rxe_pool_entry *elem)
 {
 	struct rxe_pool *pool = elem->pool;
 
@@ -297,11 +297,11 @@ void __rxe_drop_key(struct rxe_pool_entry *elem)
 	unsigned long flags;
 
 	write_lock_irqsave(&pool->pool_lock, flags);
-	__rxe_drop_key_nl(elem);
+	__rxe_drop_key__(elem);
 	write_unlock_irqrestore(&pool->pool_lock, flags);
 }
 
-void __rxe_add_index_nl(struct rxe_pool_entry *elem)
+void __rxe_add_index__(struct rxe_pool_entry *elem)
 {
 	struct rxe_pool *pool = elem->pool;
 
@@ -315,11 +315,11 @@ void __rxe_add_index(struct rxe_pool_entry *elem)
 	unsigned long flags;
 
 	write_lock_irqsave(&pool->pool_lock, flags);
-	__rxe_add_index_nl(elem);
+	__rxe_add_index__(elem);
 	write_unlock_irqrestore(&pool->pool_lock, flags);
 }
 
-void __rxe_drop_index_nl(struct rxe_pool_entry *elem)
+void __rxe_drop_index__(struct rxe_pool_entry *elem)
 {
 	struct rxe_pool *pool = elem->pool;
 
@@ -333,11 +333,11 @@ void __rxe_drop_index(struct rxe_pool_entry *elem)
 	unsigned long flags;
 
 	write_lock_irqsave(&pool->pool_lock, flags);
-	__rxe_drop_index_nl(elem);
+	__rxe_drop_index__(elem);
 	write_unlock_irqrestore(&pool->pool_lock, flags);
 }
 
-void *rxe_alloc_nl(struct rxe_pool *pool)
+void *rxe_alloc__(struct rxe_pool *pool)
 {
 	struct rxe_type_info *info = &rxe_type_info[pool->type];
 	struct rxe_pool_entry *elem;
@@ -507,7 +507,7 @@ void *rxe_pool_get_index(struct rxe_pool *pool, u32 index)
 	return obj;
 }
 
-void *rxe_pool_get_key_nl(struct rxe_pool *pool, void *key)
+void *rxe_pool_get_key__(struct rxe_pool *pool, void *key)
 {
 	struct rxe_type_info *info = &rxe_type_info[pool->type];
 	struct rb_node *node;
@@ -551,7 +551,7 @@ void *rxe_pool_get_key(struct rxe_pool *pool, void *key)
 	unsigned long flags;
 
 	read_lock_irqsave(&pool->pool_lock, flags);
-	obj = rxe_pool_get_key_nl(pool, key);
+	obj = rxe_pool_get_key__(pool, key);
 	read_unlock_irqrestore(&pool->pool_lock, flags);
 
 	return obj;
diff --git a/drivers/infiniband/sw/rxe/rxe_pool.h b/drivers/infiniband/sw/rxe/rxe_pool.h
index 373e08554c1c..b9680f9e907c 100644
--- a/drivers/infiniband/sw/rxe/rxe_pool.h
+++ b/drivers/infiniband/sw/rxe/rxe_pool.h
@@ -106,11 +106,10 @@ int rxe_pool_init(struct rxe_dev *rxe, struct rxe_pool *pool,
 /* free resources from object pool */
 void rxe_pool_cleanup(struct rxe_pool *pool);
 
-/* allocate an object from pool */
-void *rxe_alloc(struct rxe_pool *pool);
+/* allocate an object from pool holding and not holding the pool lock */
+void *rxe_alloc__(struct rxe_pool *pool);
 
-/* allocate an object from pool - no lock */
-void *rxe_alloc_nl(struct rxe_pool *pool);
+void *rxe_alloc(struct rxe_pool *pool);
 
 /* connect already allocated object to pool */
 int __rxe_add_to_pool(struct rxe_pool *pool, struct rxe_pool_entry *elem);
@@ -118,60 +117,60 @@ int __rxe_add_to_pool(struct rxe_pool *pool, struct rxe_pool_entry *elem);
 #define rxe_add_to_pool(pool, obj) __rxe_add_to_pool(pool, &(obj)->pelem)
 
 /* assign an index to an indexed object and insert object into
- *  pool's rb tree with and without holding the pool_lock
+ *  pool's rb tree holding and not holding the pool_lock
  */
-void __rxe_add_index(struct rxe_pool_entry *elem);
+void __rxe_add_index__(struct rxe_pool_entry *elem);
 
-#define rxe_add_index(obj) __rxe_add_index(&(obj)->pelem)
+#define rxe_add_index__(obj) __rxe_add_index__(&(obj)->pelem)
 
-void __rxe_add_index_nl(struct rxe_pool_entry *elem);
+void __rxe_add_index(struct rxe_pool_entry *elem);
 
-#define rxe_add_index_nl(obj) __rxe_add_index_nl(&(obj)->pelem)
+#define rxe_add_index(obj) __rxe_add_index(&(obj)->pelem)
 
 /* drop an index and remove object from rb tree
- * with and without holding the pool_lock
+ * holding and not holding the pool_lock
  */
-void __rxe_drop_index(struct rxe_pool_entry *elem);
+void __rxe_drop_index__(struct rxe_pool_entry *elem);
 
-#define rxe_drop_index(obj) __rxe_drop_index(&(obj)->pelem)
+#define rxe_drop_index__(obj) __rxe_drop_index__(&(obj)->pelem)
 
-void __rxe_drop_index_nl(struct rxe_pool_entry *elem);
+void __rxe_drop_index(struct rxe_pool_entry *elem);
 
-#define rxe_drop_index_nl(obj) __rxe_drop_index_nl(&(obj)->pelem)
+#define rxe_drop_index(obj) __rxe_drop_index(&(obj)->pelem)
 
 /* assign a key to a keyed object and insert object into
- * pool's rb tree with and without holding pool_lock
+ * pool's rb tree holding and not holding pool_lock
  */
+void __rxe_add_key__(struct rxe_pool_entry *elem, void *key);
+
+#define rxe_add_key__(obj, key) __rxe_add_key__(&(obj)->pelem, key)
+
 void __rxe_add_key(struct rxe_pool_entry *elem, void *key);
 
 #define rxe_add_key(obj, key) __rxe_add_key(&(obj)->pelem, key)
 
-void __rxe_add_key_nl(struct rxe_pool_entry *elem, void *key);
+/* remove elem from rb tree holding and not holding the pool_lock */
+void __rxe_drop_key__(struct rxe_pool_entry *elem);
 
-#define rxe_add_key_nl(obj, key) __rxe_add_key_nl(&(obj)->pelem, key)
+#define rxe_drop_key__(obj) __rxe_drop_key__(&(obj)->pelem)
 
-/* remove elem from rb tree with and without holding pool_lock */
 void __rxe_drop_key(struct rxe_pool_entry *elem);
 
 #define rxe_drop_key(obj) __rxe_drop_key(&(obj)->pelem)
 
-void __rxe_drop_key_nl(struct rxe_pool_entry *elem);
-
-#define rxe_drop_key_nl(obj) __rxe_drop_key_nl(&(obj)->pelem)
-
-/* lookup an indexed object from index with and without holding pool_lock.
+/* lookup an indexed object from index holding and not holding the pool_lock.
  * takes a reference on object
  */
-void *rxe_pool_get_index(struct rxe_pool *pool, u32 index);
+void *rxe_pool_get_index__(struct rxe_pool *pool, u32 index);
 
-void *rxe_pool_get_index_nl(struct rxe_pool *pool, u32 index);
+void *rxe_pool_get_index(struct rxe_pool *pool, u32 index);
 
-/* lookup keyed object from key with and without holding pool_lock.
+/* lookup keyed object from key holding and not holding the pool_lock.
  * takes a reference on the objecti
  */
-void *rxe_pool_get_key(struct rxe_pool *pool, void *key);
+void *rxe_pool_get_key__(struct rxe_pool *pool, void *key);
 
-void *rxe_pool_get_key_nl(struct rxe_pool *pool, void *key);
+void *rxe_pool_get_key(struct rxe_pool *pool, void *key);
 
 /* cleanup an object when all references are dropped */
 void rxe_elem_release(struct kref *kref);
-- 
2.27.0

Re: [PATCH for-next 2/5] RDMA/rxe: Fix misleading comments and names

[Jason Gunthorpe]

On Thu, Jan 21, 2021 at 10:23:10PM -0600, Bob Pearson wrote:
> The names and comments of the 'unlocked' pool APIs are very
> misleading and not what was intended. This patch replaces
> 'rxe_xxx_nl' with 'rxe_xxx__' with comments indicating that the
> caller is expected to hold the rxe pool lock.
> 
> Reported-by: Hillf Danton <hdanton@sina.com>
> Signed-off-by: Bob Pearson <rpearson@hpe.com>
> ---
>  drivers/infiniband/sw/rxe/rxe_mcast.c |  8 ++--
>  drivers/infiniband/sw/rxe/rxe_pool.c  | 22 +++++------
>  drivers/infiniband/sw/rxe/rxe_pool.h  | 55 +++++++++++++--------------
>  3 files changed, 42 insertions(+), 43 deletions(-)
> 
> diff --git a/drivers/infiniband/sw/rxe/rxe_mcast.c b/drivers/infiniband/sw/rxe/rxe_mcast.c
> index 5be47ce7d319..b9f06f87866e 100644
> --- a/drivers/infiniband/sw/rxe/rxe_mcast.c
> +++ b/drivers/infiniband/sw/rxe/rxe_mcast.c
> @@ -15,18 +15,18 @@ static struct rxe_mc_grp *create_grp(struct rxe_dev *rxe,
>  	int err;
>  	struct rxe_mc_grp *grp;
>  
> -	grp = rxe_alloc_nl(&rxe->mc_grp_pool);
> +	grp = rxe_alloc__(&rxe->mc_grp_pool);

Everything else seems fine, but this trailing __ is too weird

If a lock is supposed to be held then name it foo_locked() or locked_()

If it auto-locks then name it foo()

If there is some #define wrapper then it is 

#define foo() __foo()

Jason

RE: [PATCH for-next 2/5] RDMA/rxe: Fix misleading comments and names

[Pearson, Robert B]

-----Original Message-----
From: Jason Gunthorpe <jgg@nvidia.com> 
Sent: Friday, January 22, 2021 1:27 PM
To: Bob Pearson <rpearsonhpe@gmail.com>
Cc: zyjzyj2000@gmail.com; linux-rdma@vger.kernel.org; Pearson, Robert B <robert.pearson2@hpe.com>; Hillf Danton <hdanton@sina.com>
Subject: Re: [PATCH for-next 2/5] RDMA/rxe: Fix misleading comments and names

On Thu, Jan 21, 2021 at 10:23:10PM -0600, Bob Pearson wrote:
> The names and comments of the 'unlocked' pool APIs are very misleading 
> and not what was intended. This patch replaces 'rxe_xxx_nl' with 
> 'rxe_xxx__' with comments indicating that the caller is expected to 
> hold the rxe pool lock.
> 
> Reported-by: Hillf Danton <hdanton@sina.com>
> Signed-off-by: Bob Pearson <rpearson@hpe.com>
> ---
>  drivers/infiniband/sw/rxe/rxe_mcast.c |  8 ++--  
> drivers/infiniband/sw/rxe/rxe_pool.c  | 22 +++++------  
> drivers/infiniband/sw/rxe/rxe_pool.h  | 55 +++++++++++++--------------
>  3 files changed, 42 insertions(+), 43 deletions(-)
> 
> diff --git a/drivers/infiniband/sw/rxe/rxe_mcast.c 
> b/drivers/infiniband/sw/rxe/rxe_mcast.c
> index 5be47ce7d319..b9f06f87866e 100644
> --- a/drivers/infiniband/sw/rxe/rxe_mcast.c
> +++ b/drivers/infiniband/sw/rxe/rxe_mcast.c
> @@ -15,18 +15,18 @@ static struct rxe_mc_grp *create_grp(struct rxe_dev *rxe,
>  	int err;
>  	struct rxe_mc_grp *grp;
>  
> -	grp = rxe_alloc_nl(&rxe->mc_grp_pool);
> +	grp = rxe_alloc__(&rxe->mc_grp_pool);

Everything else seems fine, but this trailing __ is too weird

If a lock is supposed to be held then name it foo_locked() or locked_()

If it auto-locks then name it foo()

If there is some #define wrapper then it is 

#define foo() __foo()

Jason


I have both in some cases. A #define and a locked version in some cases. I'll try xxx_locked().
To be clear that means caller should hold some lock, yes?

bob

Re: [PATCH for-next 2/5] RDMA/rxe: Fix misleading comments and names

[Jason Gunthorpe]

On Fri, Jan 22, 2021 at 09:48:21PM +0000, Pearson, Robert B wrote:

> I have both in some cases. A #define and a locked version in some
> cases. I'll try xxx_locked().  To be clear that means caller should
> hold some lock, yes?

Yes

Jason

[PATCH for-next 3/5] RDMA/rxe: Remove RXE_POOL_ATOMIC

[Bob Pearson]

rxe_alloc() used the RXE_POOL_ATOMIC flag in rxe_type_info
to select GFP_ATOMIC in calls to kzalloc(). This was intended
to handle cases where an object could be created in interrupt
context. This no longer occurs since allocating those objects
has moved into the core so this flag is not necessary. An
incorrect use of this flag was still present for rxe_mc_elem
objects and is removed.

Signed-off-by: Bob Pearson <rpearson@hpe.com>
---
 drivers/infiniband/sw/rxe/rxe_pool.c | 6 +-----
 drivers/infiniband/sw/rxe/rxe_pool.h | 1 -
 2 files changed, 1 insertion(+), 6 deletions(-)

diff --git a/drivers/infiniband/sw/rxe/rxe_pool.c b/drivers/infiniband/sw/rxe/rxe_pool.c
index 80deec1e2924..7e68f99558a7 100644
--- a/drivers/infiniband/sw/rxe/rxe_pool.c
+++ b/drivers/infiniband/sw/rxe/rxe_pool.c
@@ -84,7 +84,6 @@ struct rxe_type_info rxe_type_info[RXE_NUM_TYPES] = {
 		.name		= "rxe-mc_elem",
 		.size		= sizeof(struct rxe_mc_elem),
 		.elem_offset	= offsetof(struct rxe_mc_elem, pelem),
-		.flags		= RXE_POOL_ATOMIC,
 	},
 };
 
@@ -380,8 +379,6 @@ void *rxe_alloc(struct rxe_pool *pool)
 	struct rxe_pool_entry *elem;
 	u8 *obj;
 
-	might_sleep_if(!(pool->flags & RXE_POOL_ATOMIC));
-
 	read_lock_irqsave(&pool->pool_lock, flags);
 	if (pool->state != RXE_POOL_STATE_VALID) {
 		read_unlock_irqrestore(&pool->pool_lock, flags);
@@ -397,8 +394,7 @@ void *rxe_alloc(struct rxe_pool *pool)
 	if (atomic_inc_return(&pool->num_elem) > pool->max_elem)
 		goto out_cnt;
 
-	obj = kzalloc(info->size, (pool->flags & RXE_POOL_ATOMIC) ?
-		      GFP_ATOMIC : GFP_KERNEL);
+	obj = kzalloc(info->size, GFP_KERNEL);
 	if (!obj)
 		goto out_cnt;
 
diff --git a/drivers/infiniband/sw/rxe/rxe_pool.h b/drivers/infiniband/sw/rxe/rxe_pool.h
index b9680f9e907c..f916ad4d0406 100644
--- a/drivers/infiniband/sw/rxe/rxe_pool.h
+++ b/drivers/infiniband/sw/rxe/rxe_pool.h
@@ -11,7 +11,6 @@
 #define RXE_POOL_CACHE_FLAGS	(0)
 
 enum rxe_pool_flags {
-	RXE_POOL_ATOMIC		= BIT(0),
 	RXE_POOL_INDEX		= BIT(1),
 	RXE_POOL_KEY		= BIT(2),
 	RXE_POOL_NO_ALLOC	= BIT(4),
-- 
2.27.0

[PATCH for-next 4/5] RDMA/rxe: Remove calls to ib_device_try_get/put

[Bob Pearson]

rxe_pool.c had redundant attempts to reference count
rxe objects taking references to the pools and also the
ib_device. This patch eliminates the references to the
ib_device which add no value.

Signed-off-by: Bob Pearson <rpearson@hpe.com>
---
 drivers/infiniband/sw/rxe/rxe_pool.c | 13 -------------
 1 file changed, 13 deletions(-)

diff --git a/drivers/infiniband/sw/rxe/rxe_pool.c b/drivers/infiniband/sw/rxe/rxe_pool.c
index 7e68f99558a7..157fb340a3fb 100644
--- a/drivers/infiniband/sw/rxe/rxe_pool.c
+++ b/drivers/infiniband/sw/rxe/rxe_pool.c
@@ -347,9 +347,6 @@ void *rxe_alloc__(struct rxe_pool *pool)
 
 	kref_get(&pool->ref_cnt);
 
-	if (!ib_device_try_get(&pool->rxe->ib_dev))
-		goto out_put_pool;
-
 	if (atomic_inc_return(&pool->num_elem) > pool->max_elem)
 		goto out_cnt;
 
@@ -366,7 +363,6 @@ void *rxe_alloc__(struct rxe_pool *pool)
 
 out_cnt:
 	atomic_dec(&pool->num_elem);
-	ib_device_put(&pool->rxe->ib_dev);
 out_put_pool:
 	rxe_pool_put(pool);
 	return NULL;
@@ -388,9 +384,6 @@ void *rxe_alloc(struct rxe_pool *pool)
 	kref_get(&pool->ref_cnt);
 	read_unlock_irqrestore(&pool->pool_lock, flags);
 
-	if (!ib_device_try_get(&pool->rxe->ib_dev))
-		goto out_put_pool;
-
 	if (atomic_inc_return(&pool->num_elem) > pool->max_elem)
 		goto out_cnt;
 
@@ -407,7 +400,6 @@ void *rxe_alloc(struct rxe_pool *pool)
 
 out_cnt:
 	atomic_dec(&pool->num_elem);
-	ib_device_put(&pool->rxe->ib_dev);
 out_put_pool:
 	rxe_pool_put(pool);
 	return NULL;
@@ -425,9 +417,6 @@ int __rxe_add_to_pool(struct rxe_pool *pool, struct rxe_pool_entry *elem)
 	kref_get(&pool->ref_cnt);
 	read_unlock_irqrestore(&pool->pool_lock, flags);
 
-	if (!ib_device_try_get(&pool->rxe->ib_dev))
-		goto out_put_pool;
-
 	if (atomic_inc_return(&pool->num_elem) > pool->max_elem)
 		goto out_cnt;
 
@@ -438,7 +427,6 @@ int __rxe_add_to_pool(struct rxe_pool *pool, struct rxe_pool_entry *elem)
 
 out_cnt:
 	atomic_dec(&pool->num_elem);
-	ib_device_put(&pool->rxe->ib_dev);
 out_put_pool:
 	rxe_pool_put(pool);
 	return -EINVAL;
@@ -461,7 +449,6 @@ void rxe_elem_release(struct kref *kref)
 	}
 
 	atomic_dec(&pool->num_elem);
-	ib_device_put(&pool->rxe->ib_dev);
 	rxe_pool_put(pool);
 }
 
-- 
2.27.0

[PATCH for-next 5/5] RDMA/rxe: Remove unneeded pool->flag

[Bob Pearson]

The rxe driver used the field pool->flag to mark a pool as it was
begin shut down and checked this flag in several pool APIs to
validate that the pool had not been shut dowm. This is really
unneeded because the pools were not marked invalid unless the
entire driver was being removed at which point no functional
APIs should or could be executing. This patch removes this
flag, associated enums and spinlock code, and unneeded labels.

Signed-off-by: Bob Pearson <rpearson@hpe.com>
---
 drivers/infiniband/sw/rxe/rxe_pool.c | 38 ----------------------------
 drivers/infiniband/sw/rxe/rxe_pool.h |  6 -----
 2 files changed, 44 deletions(-)

diff --git a/drivers/infiniband/sw/rxe/rxe_pool.c b/drivers/infiniband/sw/rxe/rxe_pool.c
index 157fb340a3fb..0d177a823365 100644
--- a/drivers/infiniband/sw/rxe/rxe_pool.c
+++ b/drivers/infiniband/sw/rxe/rxe_pool.c
@@ -159,8 +159,6 @@ int rxe_pool_init(
 		pool->key.key_size = rxe_type_info[type].key_size;
 	}
 
-	pool->state = RXE_POOL_STATE_VALID;
-
 out:
 	return err;
 }
@@ -169,7 +167,6 @@ static void rxe_pool_release(struct kref *kref)
 {
 	struct rxe_pool *pool = container_of(kref, struct rxe_pool, ref_cnt);
 
-	pool->state = RXE_POOL_STATE_INVALID;
 	kfree(pool->index.table);
 }
 
@@ -180,14 +177,9 @@ static void rxe_pool_put(struct rxe_pool *pool)
 
 void rxe_pool_cleanup(struct rxe_pool *pool)
 {
-	unsigned long flags;
-
-	write_lock_irqsave(&pool->pool_lock, flags);
-	pool->state = RXE_POOL_STATE_INVALID;
 	if (atomic_read(&pool->num_elem) > 0)
 		pr_warn("%s pool destroyed with unfree'd elem\n",
 			pool_name(pool));
-	write_unlock_irqrestore(&pool->pool_lock, flags);
 
 	rxe_pool_put(pool);
 }
@@ -342,9 +334,6 @@ void *rxe_alloc__(struct rxe_pool *pool)
 	struct rxe_pool_entry *elem;
 	u8 *obj;
 
-	if (pool->state != RXE_POOL_STATE_VALID)
-		return NULL;
-
 	kref_get(&pool->ref_cnt);
 
 	if (atomic_inc_return(&pool->num_elem) > pool->max_elem)
@@ -363,26 +352,17 @@ void *rxe_alloc__(struct rxe_pool *pool)
 
 out_cnt:
 	atomic_dec(&pool->num_elem);
-out_put_pool:
 	rxe_pool_put(pool);
 	return NULL;
 }
 
 void *rxe_alloc(struct rxe_pool *pool)
 {
-	unsigned long flags;
 	struct rxe_type_info *info = &rxe_type_info[pool->type];
 	struct rxe_pool_entry *elem;
 	u8 *obj;
 
-	read_lock_irqsave(&pool->pool_lock, flags);
-	if (pool->state != RXE_POOL_STATE_VALID) {
-		read_unlock_irqrestore(&pool->pool_lock, flags);
-		return NULL;
-	}
-
 	kref_get(&pool->ref_cnt);
-	read_unlock_irqrestore(&pool->pool_lock, flags);
 
 	if (atomic_inc_return(&pool->num_elem) > pool->max_elem)
 		goto out_cnt;
@@ -400,22 +380,13 @@ void *rxe_alloc(struct rxe_pool *pool)
 
 out_cnt:
 	atomic_dec(&pool->num_elem);
-out_put_pool:
 	rxe_pool_put(pool);
 	return NULL;
 }
 
 int __rxe_add_to_pool(struct rxe_pool *pool, struct rxe_pool_entry *elem)
 {
-	unsigned long flags;
-
-	read_lock_irqsave(&pool->pool_lock, flags);
-	if (pool->state != RXE_POOL_STATE_VALID) {
-		read_unlock_irqrestore(&pool->pool_lock, flags);
-		return -EINVAL;
-	}
 	kref_get(&pool->ref_cnt);
-	read_unlock_irqrestore(&pool->pool_lock, flags);
 
 	if (atomic_inc_return(&pool->num_elem) > pool->max_elem)
 		goto out_cnt;
@@ -427,7 +398,6 @@ int __rxe_add_to_pool(struct rxe_pool *pool, struct rxe_pool_entry *elem)
 
 out_cnt:
 	atomic_dec(&pool->num_elem);
-out_put_pool:
 	rxe_pool_put(pool);
 	return -EINVAL;
 }
@@ -462,9 +432,6 @@ void *rxe_pool_get_index(struct rxe_pool *pool, u32 index)
 
 	read_lock_irqsave(&pool->pool_lock, flags);
 
-	if (pool->state != RXE_POOL_STATE_VALID)
-		goto out;
-
 	node = pool->index.tree.rb_node;
 
 	while (node) {
@@ -485,7 +452,6 @@ void *rxe_pool_get_index(struct rxe_pool *pool, u32 index)
 		obj = NULL;
 	}
 
-out:
 	read_unlock_irqrestore(&pool->pool_lock, flags);
 	return obj;
 }
@@ -498,9 +464,6 @@ void *rxe_pool_get_key__(struct rxe_pool *pool, void *key)
 	u8 *obj = NULL;
 	int cmp;
 
-	if (pool->state != RXE_POOL_STATE_VALID)
-		goto out;
-
 	node = pool->key.tree.rb_node;
 
 	while (node) {
@@ -524,7 +487,6 @@ void *rxe_pool_get_key__(struct rxe_pool *pool, void *key)
 		obj = NULL;
 	}
 
-out:
 	return obj;
 }
 
diff --git a/drivers/infiniband/sw/rxe/rxe_pool.h b/drivers/infiniband/sw/rxe/rxe_pool.h
index f916ad4d0406..d259531430d7 100644
--- a/drivers/infiniband/sw/rxe/rxe_pool.h
+++ b/drivers/infiniband/sw/rxe/rxe_pool.h
@@ -46,11 +46,6 @@ struct rxe_type_info {
 
 extern struct rxe_type_info rxe_type_info[];
 
-enum rxe_pool_state {
-	RXE_POOL_STATE_INVALID,
-	RXE_POOL_STATE_VALID,
-};
-
 struct rxe_pool_entry {
 	struct rxe_pool		*pool;
 	struct kref		ref_cnt;
@@ -70,7 +65,6 @@ struct rxe_pool {
 	size_t			elem_size;
 	struct kref		ref_cnt;
 	void			(*cleanup)(struct rxe_pool_entry *obj);
-	enum rxe_pool_state	state;
 	enum rxe_pool_flags	flags;
 	enum rxe_elem_type	type;
 
-- 
2.27.0