* [PATCH 0/5] blk-mq: fixes for Ming Leis V6 patchset
@ 2019-04-23 12:29 Hannes Reinecke
2019-04-23 12:29 ` [PATCH 1/5] blk-mq: rename 'dead_hctx_XX' to 'unused_hctx_XX' Hannes Reinecke
` (4 more replies)
0 siblings, 5 replies; 6+ messages in thread
From: Hannes Reinecke @ 2019-04-23 12:29 UTC (permalink / raw)
To: Ming Lei
Cc: Christoph Hellwig, Jens Axboe, linux-nvme, linux-block, Hannes Reinecke
Hi Ming,
to clarify my comments to your patch to introduce dead_hctx_list here's
a small patchset to address my concerns.
If you agree it would possibly be best to fold it into your patchset.
Patches are relative to the 'nvme-5.2' branch of the nvme git repository
plus the 'V6' iteration of Mings patchset
'blk-mq: fix races related with freeing queue'.
Hannes Reinecke (5):
blk-mq: rename 'dead_hctx_XX' to 'unused_hctx_XX'
blk-mq: drop 'hctx_idx' argument from blk_mq_alloc_hctx()
blk-mq: remove 'nr_queue' argument in blk_mq_exit_hw_queues()
blk-mq: Set hctx pointer to NULL in blk_mq_exit_hw_queues()
blk-mq: free q->queue_hw_ctx in blk_mq_exit_queue()
block/blk-mq.c | 45 +++++++++++++++++++++++++--------------------
block/blk-mq.h | 2 +-
include/linux/blkdev.h | 6 +++---
3 files changed, 29 insertions(+), 24 deletions(-)
--
2.16.4
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH 1/5] blk-mq: rename 'dead_hctx_XX' to 'unused_hctx_XX'
2019-04-23 12:29 [PATCH 0/5] blk-mq: fixes for Ming Leis V6 patchset Hannes Reinecke
@ 2019-04-23 12:29 ` Hannes Reinecke
2019-04-23 12:29 ` [PATCH 2/5] blk-mq: drop 'hctx_idx' argument from blk_mq_alloc_hctx() Hannes Reinecke
` (3 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: Hannes Reinecke @ 2019-04-23 12:29 UTC (permalink / raw)
To: Ming Lei
Cc: Christoph Hellwig, Jens Axboe, linux-nvme, linux-block,
Hannes Reinecke, Hannes Reinecke
Signed-off-by: Hannes Reinecke <hare@suse.com>
---
block/blk-mq.c | 22 +++++++++++-----------
include/linux/blkdev.h | 6 +++---
2 files changed, 14 insertions(+), 14 deletions(-)
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 93e30c14f1e8..6f016d0cc69b 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -2261,9 +2261,9 @@ static void blk_mq_exit_hctx(struct request_queue *q,
blk_mq_remove_cpuhp(hctx);
- spin_lock(&q->dead_hctx_lock);
- list_add(&hctx->hctx_list, &q->dead_hctx_list);
- spin_unlock(&q->dead_hctx_lock);
+ spin_lock(&q->unused_hctx_lock);
+ list_add(&hctx->hctx_list, &q->unused_hctx_list);
+ spin_unlock(&q->unused_hctx_lock);
}
static void blk_mq_exit_hw_queues(struct request_queue *q,
@@ -2669,8 +2669,8 @@ void blk_mq_release(struct request_queue *q)
cancel_delayed_work_sync(&q->requeue_work);
- /* all hctx are in .dead_hctx_list now */
- list_for_each_entry_safe(hctx, next, &q->dead_hctx_list, hctx_list) {
+ /* all hctx are in .unused_hctx_list now */
+ list_for_each_entry_safe(hctx, next, &q->unused_hctx_list, hctx_list) {
list_del_init(&hctx->hctx_list);
kobject_put(&hctx->kobj);
}
@@ -2740,9 +2740,9 @@ static struct blk_mq_hw_ctx *blk_mq_alloc_and_init_hctx(
{
struct blk_mq_hw_ctx *hctx = NULL, *tmp;
- /* reuse dead hctx first */
- spin_lock(&q->dead_hctx_lock);
- list_for_each_entry(tmp, &q->dead_hctx_list, hctx_list) {
+ /* reuse hctx first */
+ spin_lock(&q->unused_hctx_lock);
+ list_for_each_entry(tmp, &q->unused_hctx_list, hctx_list) {
if (tmp->numa_node == node) {
hctx = tmp;
break;
@@ -2750,7 +2750,7 @@ static struct blk_mq_hw_ctx *blk_mq_alloc_and_init_hctx(
}
if (hctx)
list_del_init(&hctx->hctx_list);
- spin_unlock(&q->dead_hctx_lock);
+ spin_unlock(&q->unused_hctx_lock);
if (!hctx)
hctx = blk_mq_alloc_hctx(q, set, hctx_idx, node);
@@ -2866,8 +2866,8 @@ struct request_queue *blk_mq_init_allocated_queue(struct blk_mq_tag_set *set,
if (!q->queue_hw_ctx)
goto err_sys_init;
- INIT_LIST_HEAD(&q->dead_hctx_list);
- spin_lock_init(&q->dead_hctx_lock);
+ INIT_LIST_HEAD(&q->unused_hctx_list);
+ spin_lock_init(&q->unused_hctx_lock);
blk_mq_realloc_hw_ctxs(set, q);
if (!q->nr_hw_queues)
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 1325f941f0be..39e8cd1f0cd4 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -536,11 +536,11 @@ struct request_queue {
struct mutex sysfs_lock;
/*
- * for reusing dead hctx instance in case of updating
+ * for reusing hctx instances in case of updating
* nr_hw_queues
*/
- struct list_head dead_hctx_list;
- spinlock_t dead_hctx_lock;
+ struct list_head unused_hctx_list;
+ spinlock_t unused_hctx_lock;
atomic_t mq_freeze_depth;
--
2.16.4
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH 2/5] blk-mq: drop 'hctx_idx' argument from blk_mq_alloc_hctx()
2019-04-23 12:29 [PATCH 0/5] blk-mq: fixes for Ming Leis V6 patchset Hannes Reinecke
2019-04-23 12:29 ` [PATCH 1/5] blk-mq: rename 'dead_hctx_XX' to 'unused_hctx_XX' Hannes Reinecke
@ 2019-04-23 12:29 ` Hannes Reinecke
2019-04-23 12:29 ` [PATCH 3/5] blk-mq: remove 'nr_queue' argument in blk_mq_exit_hw_queues() Hannes Reinecke
` (2 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: Hannes Reinecke @ 2019-04-23 12:29 UTC (permalink / raw)
To: Ming Lei
Cc: Christoph Hellwig, Jens Axboe, linux-nvme, linux-block,
Hannes Reinecke, Hannes Reinecke
Unused.
Signed-off-by: Hannes Reinecke <hare@suse.com>
---
block/blk-mq.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 6f016d0cc69b..d16672bfa97d 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -2324,8 +2324,7 @@ static int blk_mq_init_hctx(struct request_queue *q,
static struct blk_mq_hw_ctx *
blk_mq_alloc_hctx(struct request_queue *q,
- struct blk_mq_tag_set *set,
- unsigned hctx_idx, int node)
+ struct blk_mq_tag_set *set, int node)
{
struct blk_mq_hw_ctx *hctx;
@@ -2753,7 +2752,7 @@ static struct blk_mq_hw_ctx *blk_mq_alloc_and_init_hctx(
spin_unlock(&q->unused_hctx_lock);
if (!hctx)
- hctx = blk_mq_alloc_hctx(q, set, hctx_idx, node);
+ hctx = blk_mq_alloc_hctx(q, set, node);
if (!hctx)
goto fail;
--
2.16.4
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH 3/5] blk-mq: remove 'nr_queue' argument in blk_mq_exit_hw_queues()
2019-04-23 12:29 [PATCH 0/5] blk-mq: fixes for Ming Leis V6 patchset Hannes Reinecke
2019-04-23 12:29 ` [PATCH 1/5] blk-mq: rename 'dead_hctx_XX' to 'unused_hctx_XX' Hannes Reinecke
2019-04-23 12:29 ` [PATCH 2/5] blk-mq: drop 'hctx_idx' argument from blk_mq_alloc_hctx() Hannes Reinecke
@ 2019-04-23 12:29 ` Hannes Reinecke
2019-04-23 12:29 ` [PATCH 4/5] blk-mq: Set hctx pointer to NULL " Hannes Reinecke
2019-04-23 12:29 ` [PATCH 5/5] blk-mq: free q->queue_hw_ctx in blk_mq_exit_queue() Hannes Reinecke
4 siblings, 0 replies; 6+ messages in thread
From: Hannes Reinecke @ 2019-04-23 12:29 UTC (permalink / raw)
To: Ming Lei
Cc: Christoph Hellwig, Jens Axboe, linux-nvme, linux-block,
Hannes Reinecke, Hannes Reinecke
Unused.
Signed-off-by: Hannes Reinecke <hare@suse.com>
---
block/blk-mq.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)
diff --git a/block/blk-mq.c b/block/blk-mq.c
index d16672bfa97d..3da453b11deb 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -2267,14 +2267,12 @@ static void blk_mq_exit_hctx(struct request_queue *q,
}
static void blk_mq_exit_hw_queues(struct request_queue *q,
- struct blk_mq_tag_set *set, int nr_queue)
+ struct blk_mq_tag_set *set)
{
struct blk_mq_hw_ctx *hctx;
unsigned int i;
queue_for_each_hw_ctx(q, hctx, i) {
- if (i == nr_queue)
- break;
blk_mq_debugfs_unregister_hctx(hctx);
blk_mq_exit_hctx(q, set, hctx, i);
}
@@ -2930,7 +2928,7 @@ void blk_mq_exit_queue(struct request_queue *q)
struct blk_mq_tag_set *set = q->tag_set;
blk_mq_del_queue_tag_set(q);
- blk_mq_exit_hw_queues(q, set, set->nr_hw_queues);
+ blk_mq_exit_hw_queues(q, set);
}
static int __blk_mq_alloc_rq_maps(struct blk_mq_tag_set *set)
--
2.16.4
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH 4/5] blk-mq: Set hctx pointer to NULL in blk_mq_exit_hw_queues()
2019-04-23 12:29 [PATCH 0/5] blk-mq: fixes for Ming Leis V6 patchset Hannes Reinecke
` (2 preceding siblings ...)
2019-04-23 12:29 ` [PATCH 3/5] blk-mq: remove 'nr_queue' argument in blk_mq_exit_hw_queues() Hannes Reinecke
@ 2019-04-23 12:29 ` Hannes Reinecke
2019-04-23 12:29 ` [PATCH 5/5] blk-mq: free q->queue_hw_ctx in blk_mq_exit_queue() Hannes Reinecke
4 siblings, 0 replies; 6+ messages in thread
From: Hannes Reinecke @ 2019-04-23 12:29 UTC (permalink / raw)
To: Ming Lei
Cc: Christoph Hellwig, Jens Axboe, linux-nvme, linux-block,
Hannes Reinecke, Hannes Reinecke
When clearing the hardware context we should be setting the pointer
to NULL, too, to avoid accesses to invalid hctx entries.
Signed-off-by: Hannes Reinecke <hare@suse.com>
---
block/blk-mq.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 3da453b11deb..f620462dc4d1 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -2275,6 +2275,7 @@ static void blk_mq_exit_hw_queues(struct request_queue *q,
queue_for_each_hw_ctx(q, hctx, i) {
blk_mq_debugfs_unregister_hctx(hctx);
blk_mq_exit_hctx(q, set, hctx, i);
+ q->queue_hw_ctx[i] = NULL;
}
}
--
2.16.4
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH 5/5] blk-mq: free q->queue_hw_ctx in blk_mq_exit_queue()
2019-04-23 12:29 [PATCH 0/5] blk-mq: fixes for Ming Leis V6 patchset Hannes Reinecke
` (3 preceding siblings ...)
2019-04-23 12:29 ` [PATCH 4/5] blk-mq: Set hctx pointer to NULL " Hannes Reinecke
@ 2019-04-23 12:29 ` Hannes Reinecke
4 siblings, 0 replies; 6+ messages in thread
From: Hannes Reinecke @ 2019-04-23 12:29 UTC (permalink / raw)
To: Ming Lei
Cc: Christoph Hellwig, Jens Axboe, linux-nvme, linux-block,
Hannes Reinecke, Hannes
blk_mq_exit_queue() already frees up all hardware contexts, so it should
be freeing up the holding array, too.
Signed-off-by: Hannes Reinecke <hare@suse.com.
---
block/blk-mq.c | 11 +++++++++--
block/blk-mq.h | 2 +-
2 files changed, 10 insertions(+), 3 deletions(-)
diff --git a/block/blk-mq.c b/block/blk-mq.c
index f620462dc4d1..ae873d333f5f 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -462,7 +462,8 @@ struct request *blk_mq_alloc_request_hctx(struct request_queue *q,
* Check if the hardware context is actually mapped to anything.
* If not tell the caller that it should skip this queue.
*/
- alloc_data.hctx = q->queue_hw_ctx[hctx_idx];
+ if (q->queue_hw_ctx)
+ alloc_data.hctx = q->queue_hw_ctx[hctx_idx];
if (!blk_mq_hw_queue_mapped(alloc_data.hctx)) {
blk_queue_exit(q);
return ERR_PTR(-EXDEV);
@@ -2673,7 +2674,8 @@ void blk_mq_release(struct request_queue *q)
kobject_put(&hctx->kobj);
}
- kfree(q->queue_hw_ctx);
+ /* Ensure that blk_mq_exit_queue() has been called */
+ WARN_ON(q->queue_hw_ctx);
/*
* release .mq_kobj and sw queue's kobject now because
@@ -2930,6 +2932,8 @@ void blk_mq_exit_queue(struct request_queue *q)
blk_mq_del_queue_tag_set(q);
blk_mq_exit_hw_queues(q, set);
+ kfree(q->queue_hw_ctx);
+ q->queue_hw_ctx = NULL;
}
static int __blk_mq_alloc_rq_maps(struct blk_mq_tag_set *set)
@@ -3477,6 +3481,9 @@ int blk_poll(struct request_queue *q, blk_qc_t cookie, bool spin)
if (current->plug)
blk_flush_plug_list(current->plug, false);
+ if (!q->queue_hw_ctx)
+ return 0;
+
hctx = q->queue_hw_ctx[blk_qc_t_to_queue_num(cookie)];
/*
diff --git a/block/blk-mq.h b/block/blk-mq.h
index c421e3a16e36..14589b9fca84 100644
--- a/block/blk-mq.h
+++ b/block/blk-mq.h
@@ -188,7 +188,7 @@ static inline bool blk_mq_hctx_stopped(struct blk_mq_hw_ctx *hctx)
static inline bool blk_mq_hw_queue_mapped(struct blk_mq_hw_ctx *hctx)
{
- return hctx->nr_ctx && hctx->tags;
+ return hctx && hctx->nr_ctx && hctx->tags;
}
unsigned int blk_mq_in_flight(struct request_queue *q, struct hd_struct *part);
--
2.16.4
^ permalink raw reply related [flat|nested] 6+ messages in thread
end of thread, other threads:[~2019-04-23 12:30 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-04-23 12:29 [PATCH 0/5] blk-mq: fixes for Ming Leis V6 patchset Hannes Reinecke
2019-04-23 12:29 ` [PATCH 1/5] blk-mq: rename 'dead_hctx_XX' to 'unused_hctx_XX' Hannes Reinecke
2019-04-23 12:29 ` [PATCH 2/5] blk-mq: drop 'hctx_idx' argument from blk_mq_alloc_hctx() Hannes Reinecke
2019-04-23 12:29 ` [PATCH 3/5] blk-mq: remove 'nr_queue' argument in blk_mq_exit_hw_queues() Hannes Reinecke
2019-04-23 12:29 ` [PATCH 4/5] blk-mq: Set hctx pointer to NULL " Hannes Reinecke
2019-04-23 12:29 ` [PATCH 5/5] blk-mq: free q->queue_hw_ctx in blk_mq_exit_queue() Hannes Reinecke
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