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* [PATCH 0/8] Block layer patches for kernel v5.5
@ 2019-09-30 23:00 Bart Van Assche
  2019-09-30 23:00 ` [PATCH 1/8] block: Fix three kernel-doc warnings Bart Van Assche
                   ` (8 more replies)
  0 siblings, 9 replies; 10+ messages in thread
From: Bart Van Assche @ 2019-09-30 23:00 UTC (permalink / raw)
  To: Jens Axboe; +Cc: linux-block, Christoph Hellwig, Bart Van Assche

Hi Jens,

This patch series includes the patches I prepared for kernel v5.5. Please
consider these patches for inclusion in the upstream kernel.

Thanks,

Bart.

Bart Van Assche (8):
  block: Fix three kernel-doc warnings
  block: Fix writeback throttling W=1 compiler warnings
  block: Remove request_queue.nr_queues
  block: Remove "dying" checks from sysfs callbacks
  block: Reduce sysfs_lock locking inside blk_cleanup_queue()
  block: Document all members of blk_mq_tag_set and bkl_mq_queue_map
  null_blk: Improve nullb_device_##NAME##_store() readability
  null_blk: Enable modifying 'submit_queues' after an instance has been
    configured

 block/blk-core.c              |  4 +-
 block/blk-mq-sysfs.c          | 16 ++-----
 block/blk-mq.c                |  6 +--
 block/blk-sysfs.c             |  8 ----
 block/t10-pi.c                |  8 +---
 drivers/block/null_blk_main.c | 78 +++++++++++++++++++++++------------
 include/linux/blk-mq.h        | 54 +++++++++++++++++++-----
 include/linux/blkdev.h        |  1 -
 include/trace/events/wbt.h    | 12 ++++--
 9 files changed, 114 insertions(+), 73 deletions(-)



^ permalink raw reply	[flat|nested] 10+ messages in thread

* [PATCH 1/8] block: Fix three kernel-doc warnings
  2019-09-30 23:00 [PATCH 0/8] Block layer patches for kernel v5.5 Bart Van Assche
@ 2019-09-30 23:00 ` Bart Van Assche
  2019-09-30 23:00 ` [PATCH 2/8] block: Fix writeback throttling W=1 compiler warnings Bart Van Assche
                   ` (7 subsequent siblings)
  8 siblings, 0 replies; 10+ messages in thread
From: Bart Van Assche @ 2019-09-30 23:00 UTC (permalink / raw)
  To: Jens Axboe
  Cc: linux-block, Christoph Hellwig, Bart Van Assche, Max Gurtovoy,
	Christoph Hellwig, Ming Lei, Hannes Reinecke, Johannes Thumshirn

Fix the following kernel-doc warnings:

block/t10-pi.c:242: warning: Function parameter or member 'rq' not described in 't10_pi_type3_prepare'
block/t10-pi.c:249: warning: Function parameter or member 'rq' not described in 't10_pi_type3_complete'
block/t10-pi.c:249: warning: Function parameter or member 'nr_bytes' not described in 't10_pi_type3_complete'

Cc: Max Gurtovoy <maxg@mellanox.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Hannes Reinecke <hare@suse.com>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
Fixes: 54d4e6ab91eb ("block: centralize PI remapping logic to the block layer")
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
---
 block/t10-pi.c | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/block/t10-pi.c b/block/t10-pi.c
index 9803c7e0376e..f4907d941f03 100644
--- a/block/t10-pi.c
+++ b/block/t10-pi.c
@@ -235,16 +235,12 @@ static blk_status_t t10_pi_type3_verify_ip(struct blk_integrity_iter *iter)
 	return t10_pi_verify(iter, t10_pi_ip_fn, T10_PI_TYPE3_PROTECTION);
 }
 
-/**
- * Type 3 does not have a reference tag so no remapping is required.
- */
+/* Type 3 does not have a reference tag so no remapping is required. */
 static void t10_pi_type3_prepare(struct request *rq)
 {
 }
 
-/**
- * Type 3 does not have a reference tag so no remapping is required.
- */
+/* Type 3 does not have a reference tag so no remapping is required. */
 static void t10_pi_type3_complete(struct request *rq, unsigned int nr_bytes)
 {
 }
-- 
2.23.0.444.g18eeb5a265-goog


^ permalink raw reply	[flat|nested] 10+ messages in thread

* [PATCH 2/8] block: Fix writeback throttling W=1 compiler warnings
  2019-09-30 23:00 [PATCH 0/8] Block layer patches for kernel v5.5 Bart Van Assche
  2019-09-30 23:00 ` [PATCH 1/8] block: Fix three kernel-doc warnings Bart Van Assche
@ 2019-09-30 23:00 ` Bart Van Assche
  2019-09-30 23:00 ` [PATCH 3/8] block: Remove request_queue.nr_queues Bart Van Assche
                   ` (6 subsequent siblings)
  8 siblings, 0 replies; 10+ messages in thread
From: Bart Van Assche @ 2019-09-30 23:00 UTC (permalink / raw)
  To: Jens Axboe
  Cc: linux-block, Christoph Hellwig, Bart Van Assche,
	Christoph Hellwig, Ming Lei, Hannes Reinecke, Johannes Thumshirn

Fix the following compiler warnings:

In file included from ./include/linux/bitmap.h:9,
                 from ./include/linux/cpumask.h:12,
                 from ./arch/x86/include/asm/cpumask.h:5,
                 from ./arch/x86/include/asm/msr.h:11,
                 from ./arch/x86/include/asm/processor.h:21,
                 from ./arch/x86/include/asm/cpufeature.h:5,
                 from ./arch/x86/include/asm/thread_info.h:53,
                 from ./include/linux/thread_info.h:38,
                 from ./arch/x86/include/asm/preempt.h:7,
                 from ./include/linux/preempt.h:78,
                 from ./include/linux/spinlock.h:51,
                 from ./include/linux/mmzone.h:8,
                 from ./include/linux/gfp.h:6,
                 from ./include/linux/mm.h:10,
                 from ./include/linux/bvec.h:13,
                 from ./include/linux/blk_types.h:10,
                 from block/blk-wbt.c:23:
In function 'strncpy',
    inlined from 'perf_trace_wbt_stat' at ./include/trace/events/wbt.h:15:1:
./include/linux/string.h:260:9: warning: '__builtin_strncpy' specified bound 32 equals destination size [-Wstringop-truncation]
  return __builtin_strncpy(p, q, size);
         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In function 'strncpy',
    inlined from 'perf_trace_wbt_lat' at ./include/trace/events/wbt.h:58:1:
./include/linux/string.h:260:9: warning: '__builtin_strncpy' specified bound 32 equals destination size [-Wstringop-truncation]
  return __builtin_strncpy(p, q, size);
         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In function 'strncpy',
    inlined from 'perf_trace_wbt_step' at ./include/trace/events/wbt.h:87:1:
./include/linux/string.h:260:9: warning: '__builtin_strncpy' specified bound 32 equals destination size [-Wstringop-truncation]
  return __builtin_strncpy(p, q, size);
         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In function 'strncpy',
    inlined from 'perf_trace_wbt_timer' at ./include/trace/events/wbt.h:126:1:
./include/linux/string.h:260:9: warning: '__builtin_strncpy' specified bound 32 equals destination size [-Wstringop-truncation]
  return __builtin_strncpy(p, q, size);
         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In function 'strncpy',
    inlined from 'trace_event_raw_event_wbt_stat' at ./include/trace/events/wbt.h:15:1:
./include/linux/string.h:260:9: warning: '__builtin_strncpy' specified bound 32 equals destination size [-Wstringop-truncation]
  return __builtin_strncpy(p, q, size);
         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In function 'strncpy',
    inlined from 'trace_event_raw_event_wbt_lat' at ./include/trace/events/wbt.h:58:1:
./include/linux/string.h:260:9: warning: '__builtin_strncpy' specified bound 32 equals destination size [-Wstringop-truncation]
  return __builtin_strncpy(p, q, size);
         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In function 'strncpy',
    inlined from 'trace_event_raw_event_wbt_timer' at ./include/trace/events/wbt.h:126:1:
./include/linux/string.h:260:9: warning: '__builtin_strncpy' specified bound 32 equals destination size [-Wstringop-truncation]
  return __builtin_strncpy(p, q, size);
         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In function 'strncpy',
    inlined from 'trace_event_raw_event_wbt_step' at ./include/trace/events/wbt.h:87:1:
./include/linux/string.h:260:9: warning: '__builtin_strncpy' specified bound 32 equals destination size [-Wstringop-truncation]
  return __builtin_strncpy(p, q, size);
         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Cc: Christoph Hellwig <hch@infradead.org>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Hannes Reinecke <hare@suse.com>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
Fixes: e34cbd307477 ("blk-wbt: add general throttling mechanism"; v4.10).
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
---
 include/trace/events/wbt.h | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/include/trace/events/wbt.h b/include/trace/events/wbt.h
index b048694070e2..37342a13c9cb 100644
--- a/include/trace/events/wbt.h
+++ b/include/trace/events/wbt.h
@@ -33,7 +33,8 @@ TRACE_EVENT(wbt_stat,
 	),
 
 	TP_fast_assign(
-		strncpy(__entry->name, dev_name(bdi->dev), 32);
+		strlcpy(__entry->name, dev_name(bdi->dev),
+			ARRAY_SIZE(__entry->name));
 		__entry->rmean		= stat[0].mean;
 		__entry->rmin		= stat[0].min;
 		__entry->rmax		= stat[0].max;
@@ -67,7 +68,8 @@ TRACE_EVENT(wbt_lat,
 	),
 
 	TP_fast_assign(
-		strncpy(__entry->name, dev_name(bdi->dev), 32);
+		strlcpy(__entry->name, dev_name(bdi->dev),
+			ARRAY_SIZE(__entry->name));
 		__entry->lat = div_u64(lat, 1000);
 	),
 
@@ -103,7 +105,8 @@ TRACE_EVENT(wbt_step,
 	),
 
 	TP_fast_assign(
-		strncpy(__entry->name, dev_name(bdi->dev), 32);
+		strlcpy(__entry->name, dev_name(bdi->dev),
+			ARRAY_SIZE(__entry->name));
 		__entry->msg	= msg;
 		__entry->step	= step;
 		__entry->window	= div_u64(window, 1000);
@@ -138,7 +141,8 @@ TRACE_EVENT(wbt_timer,
 	),
 
 	TP_fast_assign(
-		strncpy(__entry->name, dev_name(bdi->dev), 32);
+		strlcpy(__entry->name, dev_name(bdi->dev),
+			ARRAY_SIZE(__entry->name));
 		__entry->status		= status;
 		__entry->step		= step;
 		__entry->inflight	= inflight;
-- 
2.23.0.444.g18eeb5a265-goog


^ permalink raw reply	[flat|nested] 10+ messages in thread

* [PATCH 3/8] block: Remove request_queue.nr_queues
  2019-09-30 23:00 [PATCH 0/8] Block layer patches for kernel v5.5 Bart Van Assche
  2019-09-30 23:00 ` [PATCH 1/8] block: Fix three kernel-doc warnings Bart Van Assche
  2019-09-30 23:00 ` [PATCH 2/8] block: Fix writeback throttling W=1 compiler warnings Bart Van Assche
@ 2019-09-30 23:00 ` Bart Van Assche
  2019-09-30 23:00 ` [PATCH 4/8] block: Remove "dying" checks from sysfs callbacks Bart Van Assche
                   ` (5 subsequent siblings)
  8 siblings, 0 replies; 10+ messages in thread
From: Bart Van Assche @ 2019-09-30 23:00 UTC (permalink / raw)
  To: Jens Axboe
  Cc: linux-block, Christoph Hellwig, Bart Van Assche,
	Christoph Hellwig, Ming Lei, Hannes Reinecke, Johannes Thumshirn

Commit 897bb0c7f1ea ("blk-mq: Use proper cpumask iterator"; v4.6)
removed the last use of request_queue.nr_queues from outside
blk_mq_init_allocate_queue(). Remove this member variable to make
struct request_queue smaller. This patch does not change any
functionality.

Cc: Christoph Hellwig <hch@infradead.org>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Hannes Reinecke <hare@suse.com>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
---
 block/blk-mq.c         | 6 +++---
 include/linux/blkdev.h | 1 -
 2 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 29275f5a996f..25b8a9b44a31 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -2867,9 +2867,9 @@ struct request_queue *blk_mq_init_allocated_queue(struct blk_mq_tag_set *set,
 	/* init q->mq_kobj and sw queues' kobjects */
 	blk_mq_sysfs_init(q);
 
-	q->nr_queues = nr_hw_queues(set);
-	q->queue_hw_ctx = kcalloc_node(q->nr_queues, sizeof(*(q->queue_hw_ctx)),
-						GFP_KERNEL, set->numa_node);
+	q->queue_hw_ctx = kcalloc_node(nr_hw_queues(set),
+				       sizeof(*(q->queue_hw_ctx)), GFP_KERNEL,
+				       set->numa_node);
 	if (!q->queue_hw_ctx)
 		goto err_sys_init;
 
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 6032bb740cf4..fe32e07c5e3c 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -411,7 +411,6 @@ struct request_queue {
 
 	/* sw queues */
 	struct blk_mq_ctx __percpu	*queue_ctx;
-	unsigned int		nr_queues;
 
 	unsigned int		queue_depth;
 
-- 
2.23.0.444.g18eeb5a265-goog


^ permalink raw reply	[flat|nested] 10+ messages in thread

* [PATCH 4/8] block: Remove "dying" checks from sysfs callbacks
  2019-09-30 23:00 [PATCH 0/8] Block layer patches for kernel v5.5 Bart Van Assche
                   ` (2 preceding siblings ...)
  2019-09-30 23:00 ` [PATCH 3/8] block: Remove request_queue.nr_queues Bart Van Assche
@ 2019-09-30 23:00 ` Bart Van Assche
  2019-09-30 23:00 ` [PATCH 5/8] block: Reduce sysfs_lock locking inside blk_cleanup_queue() Bart Van Assche
                   ` (4 subsequent siblings)
  8 siblings, 0 replies; 10+ messages in thread
From: Bart Van Assche @ 2019-09-30 23:00 UTC (permalink / raw)
  To: Jens Axboe
  Cc: linux-block, Christoph Hellwig, Bart Van Assche,
	Christoph Hellwig, Ming Lei, Hannes Reinecke, Johannes Thumshirn

Block drivers must call del_gendisk() before blk_cleanup_queue().
del_gendisk() calls kobject_del() and kobject_del() waits until any
ongoing sysfs callback functions have finished. In other words, the
sysfs callback functions won't be called for a queue in the dying
state. Hence remove the "dying" checks from the sysfs callback
functions.

Cc: Christoph Hellwig <hch@infradead.org>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Hannes Reinecke <hare@suse.com>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
---
 block/blk-core.c     |  2 ++
 block/blk-mq-sysfs.c | 16 ++++------------
 block/blk-sysfs.c    |  8 --------
 3 files changed, 6 insertions(+), 20 deletions(-)

diff --git a/block/blk-core.c b/block/blk-core.c
index d5e668ec751b..8b51d9ec8ae3 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -336,6 +336,8 @@ EXPORT_SYMBOL_GPL(blk_set_queue_dying);
  */
 void blk_cleanup_queue(struct request_queue *q)
 {
+	WARN_ON_ONCE(blk_queue_registered(q));
+
 	/* mark @q DYING, no new request or merges will be allowed afterwards */
 	mutex_lock(&q->sysfs_lock);
 	blk_set_queue_dying(q);
diff --git a/block/blk-mq-sysfs.c b/block/blk-mq-sysfs.c
index a0d3ce30fa08..81a273b43329 100644
--- a/block/blk-mq-sysfs.c
+++ b/block/blk-mq-sysfs.c
@@ -74,10 +74,8 @@ static ssize_t blk_mq_sysfs_show(struct kobject *kobj, struct attribute *attr,
 	if (!entry->show)
 		return -EIO;
 
-	res = -ENOENT;
 	mutex_lock(&q->sysfs_lock);
-	if (!blk_queue_dying(q))
-		res = entry->show(ctx, page);
+	res = entry->show(ctx, page);
 	mutex_unlock(&q->sysfs_lock);
 	return res;
 }
@@ -97,10 +95,8 @@ static ssize_t blk_mq_sysfs_store(struct kobject *kobj, struct attribute *attr,
 	if (!entry->store)
 		return -EIO;
 
-	res = -ENOENT;
 	mutex_lock(&q->sysfs_lock);
-	if (!blk_queue_dying(q))
-		res = entry->store(ctx, page, length);
+	res = entry->store(ctx, page, length);
 	mutex_unlock(&q->sysfs_lock);
 	return res;
 }
@@ -120,10 +116,8 @@ static ssize_t blk_mq_hw_sysfs_show(struct kobject *kobj,
 	if (!entry->show)
 		return -EIO;
 
-	res = -ENOENT;
 	mutex_lock(&q->sysfs_lock);
-	if (!blk_queue_dying(q))
-		res = entry->show(hctx, page);
+	res = entry->show(hctx, page);
 	mutex_unlock(&q->sysfs_lock);
 	return res;
 }
@@ -144,10 +138,8 @@ static ssize_t blk_mq_hw_sysfs_store(struct kobject *kobj,
 	if (!entry->store)
 		return -EIO;
 
-	res = -ENOENT;
 	mutex_lock(&q->sysfs_lock);
-	if (!blk_queue_dying(q))
-		res = entry->store(hctx, page, length);
+	res = entry->store(hctx, page, length);
 	mutex_unlock(&q->sysfs_lock);
 	return res;
 }
diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
index b82736c781c5..80df16be9f52 100644
--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c
@@ -802,10 +802,6 @@ queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
 	if (!entry->show)
 		return -EIO;
 	mutex_lock(&q->sysfs_lock);
-	if (blk_queue_dying(q)) {
-		mutex_unlock(&q->sysfs_lock);
-		return -ENOENT;
-	}
 	res = entry->show(q, page);
 	mutex_unlock(&q->sysfs_lock);
 	return res;
@@ -824,10 +820,6 @@ queue_attr_store(struct kobject *kobj, struct attribute *attr,
 
 	q = container_of(kobj, struct request_queue, kobj);
 	mutex_lock(&q->sysfs_lock);
-	if (blk_queue_dying(q)) {
-		mutex_unlock(&q->sysfs_lock);
-		return -ENOENT;
-	}
 	res = entry->store(q, page, length);
 	mutex_unlock(&q->sysfs_lock);
 	return res;
-- 
2.23.0.444.g18eeb5a265-goog


^ permalink raw reply	[flat|nested] 10+ messages in thread

* [PATCH 5/8] block: Reduce sysfs_lock locking inside blk_cleanup_queue()
  2019-09-30 23:00 [PATCH 0/8] Block layer patches for kernel v5.5 Bart Van Assche
                   ` (3 preceding siblings ...)
  2019-09-30 23:00 ` [PATCH 4/8] block: Remove "dying" checks from sysfs callbacks Bart Van Assche
@ 2019-09-30 23:00 ` Bart Van Assche
  2019-09-30 23:00 ` [PATCH 6/8] block: Document all members of blk_mq_tag_set and bkl_mq_queue_map Bart Van Assche
                   ` (3 subsequent siblings)
  8 siblings, 0 replies; 10+ messages in thread
From: Bart Van Assche @ 2019-09-30 23:00 UTC (permalink / raw)
  To: Jens Axboe
  Cc: linux-block, Christoph Hellwig, Bart Van Assche,
	Christoph Hellwig, Ming Lei, Hannes Reinecke, Johannes Thumshirn

Since blk_cleanup_queue() is called after blk_unregister_queue() and
since that last function removes all sysfs attributes, serializing
any code in blk_cleanup_queue() against sysfs callback methods nor against
I/O scheduler changes is necessary. Hence remove the syfs_lock locking
calls from the start of blk_cleanup_queue().

Cc: Christoph Hellwig <hch@infradead.org>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Hannes Reinecke <hare@suse.com>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
---
 block/blk-core.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/block/blk-core.c b/block/blk-core.c
index 8b51d9ec8ae3..ae506ac2dd48 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -339,13 +339,11 @@ void blk_cleanup_queue(struct request_queue *q)
 	WARN_ON_ONCE(blk_queue_registered(q));
 
 	/* mark @q DYING, no new request or merges will be allowed afterwards */
-	mutex_lock(&q->sysfs_lock);
 	blk_set_queue_dying(q);
 
 	blk_queue_flag_set(QUEUE_FLAG_NOMERGES, q);
 	blk_queue_flag_set(QUEUE_FLAG_NOXMERGES, q);
 	blk_queue_flag_set(QUEUE_FLAG_DYING, q);
-	mutex_unlock(&q->sysfs_lock);
 
 	/*
 	 * Drain all requests queued before DYING marking. Set DEAD flag to
-- 
2.23.0.444.g18eeb5a265-goog


^ permalink raw reply	[flat|nested] 10+ messages in thread

* [PATCH 6/8] block: Document all members of blk_mq_tag_set and bkl_mq_queue_map
  2019-09-30 23:00 [PATCH 0/8] Block layer patches for kernel v5.5 Bart Van Assche
                   ` (4 preceding siblings ...)
  2019-09-30 23:00 ` [PATCH 5/8] block: Reduce sysfs_lock locking inside blk_cleanup_queue() Bart Van Assche
@ 2019-09-30 23:00 ` Bart Van Assche
  2019-09-30 23:00 ` [PATCH 7/8] null_blk: Improve nullb_device_##NAME##_store() readability Bart Van Assche
                   ` (2 subsequent siblings)
  8 siblings, 0 replies; 10+ messages in thread
From: Bart Van Assche @ 2019-09-30 23:00 UTC (permalink / raw)
  To: Jens Axboe
  Cc: linux-block, Christoph Hellwig, Bart Van Assche,
	Christoph Hellwig, Ming Lei, Hannes Reinecke, Johannes Thumshirn

The meaning of several member variables of these two data structures is
nontrivial. Hence document all member variables using the kernel-doc
syntax.

Cc: Christoph Hellwig <hch@infradead.org>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Hannes Reinecke <hare@suse.com>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
---
 include/linux/blk-mq.h | 54 +++++++++++++++++++++++++++++++++---------
 1 file changed, 43 insertions(+), 11 deletions(-)

diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index 0bf056de5cc3..a96b5cc957ab 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -76,6 +76,16 @@ struct blk_mq_hw_ctx {
 	struct srcu_struct	srcu[0];
 };
 
+/**
+ * struct blk_mq_queue_map - ctx -> hctx mapping
+ * @mq_map:       CPU ID to hardware queue index map. This is an array
+ *	with nr_cpu_ids elements. Each element has a value in the range
+ *	[@queue_offset, @queue_offset + @nr_queues).
+ * @nr_queues:    Number of hardware queues to map CPU IDs onto.
+ * @queue_offset: First hardware queue to map onto. Used by the PCIe NVMe
+ *	driver to map each hardware queue type (enum hctx_type) onto a distinct
+ *	set of hardware queues.
+ */
 struct blk_mq_queue_map {
 	unsigned int *mq_map;
 	unsigned int nr_queues;
@@ -90,23 +100,45 @@ enum hctx_type {
 	HCTX_MAX_TYPES,
 };
 
+/**
+ * struct blk_mq_tag_set - tag set that can be shared between request queues
+ * @map:	   One or more ctx -> hctx mappings. One map exists for each
+ *		   hardware queue type (enum hctx_type) that the driver wishes
+ *		   to support. There are no restrictions on maps being of the
+ *		   same size, and it's perfectly legal to share maps between
+ *		   types.
+ * @nr_maps:	   Number of elements in the @map array. A number in the range
+ *		   [1, HCTX_MAX_TYPES].
+ * @ops:	   Pointers to functions that implement block driver behavior.
+ * @nr_hw_queues:  Number of hardware queues supported by the block driver that
+ *		   owns this data structure.
+ * @queue_depth:   Number of tags per hardware queue, reserved tags included.
+ * @reserved_tags: Number of tags to set aside for BLK_MQ_REQ_RESERVED tag
+ *		   allocations.
+ * @cmd_size:	   Number of additional bytes to allocate per request. The block
+ *		   driver owns these additional bytes.
+ * @numa_node:	   NUMA node the storage adapter has been connected to.
+ * @timeout:	   Request processing timeout in jiffies.
+ * @flags:	   Zero or more BLK_MQ_F_* flags.
+ * @driver_data:   Pointer to data owned by the block driver that created this
+ *		   tag set.
+ * @tags:	   Tag sets. One tag set per hardware queue. Has @nr_hw_queues
+ *		   elements.
+ * @tag_list_lock: Serializes tag_list accesses.
+ * @tag_list:	   List of the request queues that use this tag set. See also
+ *		   request_queue.tag_set_list.
+ */
 struct blk_mq_tag_set {
-	/*
-	 * map[] holds ctx -> hctx mappings, one map exists for each type
-	 * that the driver wishes to support. There are no restrictions
-	 * on maps being of the same size, and it's perfectly legal to
-	 * share maps between types.
-	 */
 	struct blk_mq_queue_map	map[HCTX_MAX_TYPES];
-	unsigned int		nr_maps;	/* nr entries in map[] */
+	unsigned int		nr_maps;
 	const struct blk_mq_ops	*ops;
-	unsigned int		nr_hw_queues;	/* nr hw queues across maps */
-	unsigned int		queue_depth;	/* max hw supported */
+	unsigned int		nr_hw_queues;
+	unsigned int		queue_depth;
 	unsigned int		reserved_tags;
-	unsigned int		cmd_size;	/* per-request extra data */
+	unsigned int		cmd_size;
 	int			numa_node;
 	unsigned int		timeout;
-	unsigned int		flags;		/* BLK_MQ_F_* */
+	unsigned int		flags;
 	void			*driver_data;
 
 	struct blk_mq_tags	**tags;
-- 
2.23.0.444.g18eeb5a265-goog


^ permalink raw reply	[flat|nested] 10+ messages in thread

* [PATCH 7/8] null_blk: Improve nullb_device_##NAME##_store() readability
  2019-09-30 23:00 [PATCH 0/8] Block layer patches for kernel v5.5 Bart Van Assche
                   ` (5 preceding siblings ...)
  2019-09-30 23:00 ` [PATCH 6/8] block: Document all members of blk_mq_tag_set and bkl_mq_queue_map Bart Van Assche
@ 2019-09-30 23:00 ` Bart Van Assche
  2019-09-30 23:00 ` [PATCH 8/8] null_blk: Enable modifying 'submit_queues' after an instance has been configured Bart Van Assche
  2019-10-02  3:28 ` [PATCH 0/8] Block layer patches for kernel v5.5 Jens Axboe
  8 siblings, 0 replies; 10+ messages in thread
From: Bart Van Assche @ 2019-09-30 23:00 UTC (permalink / raw)
  To: Jens Axboe
  Cc: linux-block, Christoph Hellwig, Bart Van Assche,
	Christoph Hellwig, Ming Lei, Hannes Reinecke, Johannes Thumshirn

Introduce a local variable to make the code easier to read. This patch
does not change any functionality but makes the next patch in this
series easier to read.

Cc: Christoph Hellwig <hch@infradead.org>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Hannes Reinecke <hare@suse.com>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
---
 drivers/block/null_blk_main.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/block/null_blk_main.c b/drivers/block/null_blk_main.c
index 0e7da5015ccd..f5747cfd806f 100644
--- a/drivers/block/null_blk_main.c
+++ b/drivers/block/null_blk_main.c
@@ -274,10 +274,11 @@ static ssize_t									\
 nullb_device_##NAME##_store(struct config_item *item, const char *page,		\
 			    size_t count)					\
 {										\
-	if (test_bit(NULLB_DEV_FL_CONFIGURED, &to_nullb_device(item)->flags))	\
+	struct nullb_device *dev = to_nullb_device(item);			\
+										\
+	if (test_bit(NULLB_DEV_FL_CONFIGURED, &dev->flags))			\
 		return -EBUSY;							\
-	return nullb_device_##TYPE##_attr_store(				\
-			&to_nullb_device(item)->NAME, page, count);		\
+	return nullb_device_##TYPE##_attr_store(&dev->NAME, page, count);	\
 }										\
 CONFIGFS_ATTR(nullb_device_, NAME);
 
-- 
2.23.0.444.g18eeb5a265-goog


^ permalink raw reply	[flat|nested] 10+ messages in thread

* [PATCH 8/8] null_blk: Enable modifying 'submit_queues' after an instance has been configured
  2019-09-30 23:00 [PATCH 0/8] Block layer patches for kernel v5.5 Bart Van Assche
                   ` (6 preceding siblings ...)
  2019-09-30 23:00 ` [PATCH 7/8] null_blk: Improve nullb_device_##NAME##_store() readability Bart Van Assche
@ 2019-09-30 23:00 ` Bart Van Assche
  2019-10-02  3:28 ` [PATCH 0/8] Block layer patches for kernel v5.5 Jens Axboe
  8 siblings, 0 replies; 10+ messages in thread
From: Bart Van Assche @ 2019-09-30 23:00 UTC (permalink / raw)
  To: Jens Axboe
  Cc: linux-block, Christoph Hellwig, Bart Van Assche,
	Christoph Hellwig, Ming Lei, Hannes Reinecke, Johannes Thumshirn

This patch makes it possible to test blk_mq_update_nr_hw_queues() from
inside a VM.

Cc: Christoph Hellwig <hch@infradead.org>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Hannes Reinecke <hare@suse.com>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
---
 drivers/block/null_blk_main.c | 75 +++++++++++++++++++++++------------
 1 file changed, 50 insertions(+), 25 deletions(-)

diff --git a/drivers/block/null_blk_main.c b/drivers/block/null_blk_main.c
index f5747cfd806f..f5e0dffb4624 100644
--- a/drivers/block/null_blk_main.c
+++ b/drivers/block/null_blk_main.c
@@ -227,7 +227,7 @@ static ssize_t nullb_device_uint_attr_store(unsigned int *val,
 	int result;
 
 	result = kstrtouint(page, 0, &tmp);
-	if (result)
+	if (result < 0)
 		return result;
 
 	*val = tmp;
@@ -241,7 +241,7 @@ static ssize_t nullb_device_ulong_attr_store(unsigned long *val,
 	unsigned long tmp;
 
 	result = kstrtoul(page, 0, &tmp);
-	if (result)
+	if (result < 0)
 		return result;
 
 	*val = tmp;
@@ -255,7 +255,7 @@ static ssize_t nullb_device_bool_attr_store(bool *val, const char *page,
 	int result;
 
 	result = kstrtobool(page,  &tmp);
-	if (result)
+	if (result < 0)
 		return result;
 
 	*val = tmp;
@@ -263,7 +263,7 @@ static ssize_t nullb_device_bool_attr_store(bool *val, const char *page,
 }
 
 /* The following macro should only be used with TYPE = {uint, ulong, bool}. */
-#define NULLB_DEVICE_ATTR(NAME, TYPE)						\
+#define NULLB_DEVICE_ATTR(NAME, TYPE, APPLY)					\
 static ssize_t									\
 nullb_device_##NAME##_show(struct config_item *item, char *page)		\
 {										\
@@ -274,32 +274,57 @@ static ssize_t									\
 nullb_device_##NAME##_store(struct config_item *item, const char *page,		\
 			    size_t count)					\
 {										\
+	int (*apply_fn)(struct nullb_device *dev, TYPE new_value) = APPLY;	\
 	struct nullb_device *dev = to_nullb_device(item);			\
+	TYPE new_value;								\
+	int ret;								\
 										\
-	if (test_bit(NULLB_DEV_FL_CONFIGURED, &dev->flags))			\
-		return -EBUSY;							\
-	return nullb_device_##TYPE##_attr_store(&dev->NAME, page, count);	\
+	ret = nullb_device_##TYPE##_attr_store(&new_value, page, count);	\
+	if (ret < 0)								\
+		return ret;							\
+	if (apply_fn)								\
+		ret = apply_fn(dev, new_value);					\
+	else if (test_bit(NULLB_DEV_FL_CONFIGURED, &dev->flags)) 		\
+		ret = -EBUSY;							\
+	if (ret < 0)								\
+		return ret;							\
+	dev->NAME = new_value;							\
+	return count;								\
 }										\
 CONFIGFS_ATTR(nullb_device_, NAME);
 
-NULLB_DEVICE_ATTR(size, ulong);
-NULLB_DEVICE_ATTR(completion_nsec, ulong);
-NULLB_DEVICE_ATTR(submit_queues, uint);
-NULLB_DEVICE_ATTR(home_node, uint);
-NULLB_DEVICE_ATTR(queue_mode, uint);
-NULLB_DEVICE_ATTR(blocksize, uint);
-NULLB_DEVICE_ATTR(irqmode, uint);
-NULLB_DEVICE_ATTR(hw_queue_depth, uint);
-NULLB_DEVICE_ATTR(index, uint);
-NULLB_DEVICE_ATTR(blocking, bool);
-NULLB_DEVICE_ATTR(use_per_node_hctx, bool);
-NULLB_DEVICE_ATTR(memory_backed, bool);
-NULLB_DEVICE_ATTR(discard, bool);
-NULLB_DEVICE_ATTR(mbps, uint);
-NULLB_DEVICE_ATTR(cache_size, ulong);
-NULLB_DEVICE_ATTR(zoned, bool);
-NULLB_DEVICE_ATTR(zone_size, ulong);
-NULLB_DEVICE_ATTR(zone_nr_conv, uint);
+static int nullb_apply_submit_queues(struct nullb_device *dev,
+				     unsigned int submit_queues)
+{
+	struct nullb *nullb = dev->nullb;
+	struct blk_mq_tag_set *set;
+
+	if (!nullb)
+		return 0;
+
+	set = nullb->tag_set;
+	blk_mq_update_nr_hw_queues(set, submit_queues);
+	return set->nr_hw_queues == submit_queues ? 0 : -ENOMEM;
+}
+
+NULLB_DEVICE_ATTR(size, ulong, NULL);
+NULLB_DEVICE_ATTR(completion_nsec, ulong, NULL);
+NULLB_DEVICE_ATTR(submit_queues, uint, nullb_apply_submit_queues);
+NULLB_DEVICE_ATTR(home_node, uint, NULL);
+NULLB_DEVICE_ATTR(queue_mode, uint, NULL);
+NULLB_DEVICE_ATTR(blocksize, uint, NULL);
+NULLB_DEVICE_ATTR(irqmode, uint, NULL);
+NULLB_DEVICE_ATTR(hw_queue_depth, uint, NULL);
+NULLB_DEVICE_ATTR(index, uint, NULL);
+NULLB_DEVICE_ATTR(blocking, bool, NULL);
+NULLB_DEVICE_ATTR(use_per_node_hctx, bool, NULL);
+NULLB_DEVICE_ATTR(memory_backed, bool, NULL);
+NULLB_DEVICE_ATTR(discard, bool, NULL);
+NULLB_DEVICE_ATTR(mbps, uint, NULL);
+NULLB_DEVICE_ATTR(cache_size, ulong, NULL);
+NULLB_DEVICE_ATTR(zoned, bool, NULL);
+NULLB_DEVICE_ATTR(zone_size, ulong, NULL);
+NULLB_DEVICE_ATTR(zone_nr_conv, uint, NULL);
 
 static ssize_t nullb_device_power_show(struct config_item *item, char *page)
 {
-- 
2.23.0.444.g18eeb5a265-goog


^ permalink raw reply	[flat|nested] 10+ messages in thread

* Re: [PATCH 0/8] Block layer patches for kernel v5.5
  2019-09-30 23:00 [PATCH 0/8] Block layer patches for kernel v5.5 Bart Van Assche
                   ` (7 preceding siblings ...)
  2019-09-30 23:00 ` [PATCH 8/8] null_blk: Enable modifying 'submit_queues' after an instance has been configured Bart Van Assche
@ 2019-10-02  3:28 ` Jens Axboe
  8 siblings, 0 replies; 10+ messages in thread
From: Jens Axboe @ 2019-10-02  3:28 UTC (permalink / raw)
  To: Bart Van Assche; +Cc: linux-block, Christoph Hellwig

On 9/30/19 5:00 PM, Bart Van Assche wrote:
> Hi Jens,
> 
> This patch series includes the patches I prepared for kernel v5.5. Please
> consider these patches for inclusion in the upstream kernel.

Thanks Bart, applied.

-- 
Jens Axboe


^ permalink raw reply	[flat|nested] 10+ messages in thread

end of thread, back to index

Thread overview: 10+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-09-30 23:00 [PATCH 0/8] Block layer patches for kernel v5.5 Bart Van Assche
2019-09-30 23:00 ` [PATCH 1/8] block: Fix three kernel-doc warnings Bart Van Assche
2019-09-30 23:00 ` [PATCH 2/8] block: Fix writeback throttling W=1 compiler warnings Bart Van Assche
2019-09-30 23:00 ` [PATCH 3/8] block: Remove request_queue.nr_queues Bart Van Assche
2019-09-30 23:00 ` [PATCH 4/8] block: Remove "dying" checks from sysfs callbacks Bart Van Assche
2019-09-30 23:00 ` [PATCH 5/8] block: Reduce sysfs_lock locking inside blk_cleanup_queue() Bart Van Assche
2019-09-30 23:00 ` [PATCH 6/8] block: Document all members of blk_mq_tag_set and bkl_mq_queue_map Bart Van Assche
2019-09-30 23:00 ` [PATCH 7/8] null_blk: Improve nullb_device_##NAME##_store() readability Bart Van Assche
2019-09-30 23:00 ` [PATCH 8/8] null_blk: Enable modifying 'submit_queues' after an instance has been configured Bart Van Assche
2019-10-02  3:28 ` [PATCH 0/8] Block layer patches for kernel v5.5 Jens Axboe

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