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| author | Ming Lei <ming.lei@redhat.com> | 2025-10-15 18:30:39 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-10-23 16:24:37 +0200 |
| commit | 46ef903d8c0b99b6738dcb936015584236b94658 (patch) | |
| tree | 581b8bf20e19163ee8da6be14cea458873916185 /block | |
| parent | 4f487c64b7550efd171abdffdf9b239c77d9f9b9 (diff) | |
| download | linux-46ef903d8c0b99b6738dcb936015584236b94658.tar.gz linux-46ef903d8c0b99b6738dcb936015584236b94658.tar.bz2 linux-46ef903d8c0b99b6738dcb936015584236b94658.zip | |
block: Remove elevator_lock usage from blkg_conf frozen operations
[ Upstream commit 08823e89e3e269bf4c4a20b4c24a8119920cc7a4 ]
Remove the acquisition and release of q->elevator_lock in the
blkg_conf_open_bdev_frozen() and blkg_conf_exit_frozen() functions. The
elevator lock is no longer needed in these code paths since commit
78c271344b6f ("block: move wbt_enable_default() out of queue freezing
from sched ->exit()") which introduces `disk->rqos_state_mutex` for
protecting wbt state change, and not necessary to abuse elevator_lock
for this purpose.
This change helps to solve the lockdep warning reported from Yu Kuai[1].
Pass blktests/throtl with lockdep enabled.
Links: https://lore.kernel.org/linux-block/e5e7ac3f-2063-473a-aafb-4d8d43e5576e@yukuai.org.cn/ [1]
Fixes: commit 78c271344b6f ("block: move wbt_enable_default() out of queue freezing from sched ->exit()")
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Nilay Shroff <nilay@linux.ibm.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'block')
| -rw-r--r-- | block/blk-cgroup.c | 13 |
1 files changed, 4 insertions, 9 deletions
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c index 7246fc256315..091e9623bc29 100644 --- a/block/blk-cgroup.c +++ b/block/blk-cgroup.c @@ -812,8 +812,7 @@ int blkg_conf_open_bdev(struct blkg_conf_ctx *ctx) } /* * Similar to blkg_conf_open_bdev, but additionally freezes the queue, - * acquires q->elevator_lock, and ensures the correct locking order - * between q->elevator_lock and q->rq_qos_mutex. + * ensures the correct locking order between freeze queue and q->rq_qos_mutex. * * This function returns negative error on failure. On success it returns * memflags which must be saved and later passed to blkg_conf_exit_frozen @@ -834,13 +833,11 @@ unsigned long __must_check blkg_conf_open_bdev_frozen(struct blkg_conf_ctx *ctx) * At this point, we haven’t started protecting anything related to QoS, * so we release q->rq_qos_mutex here, which was first acquired in blkg_ * conf_open_bdev. Later, we re-acquire q->rq_qos_mutex after freezing - * the queue and acquiring q->elevator_lock to maintain the correct - * locking order. + * the queue to maintain the correct locking order. */ mutex_unlock(&ctx->bdev->bd_queue->rq_qos_mutex); memflags = blk_mq_freeze_queue(ctx->bdev->bd_queue); - mutex_lock(&ctx->bdev->bd_queue->elevator_lock); mutex_lock(&ctx->bdev->bd_queue->rq_qos_mutex); return memflags; @@ -1002,9 +999,8 @@ void blkg_conf_exit(struct blkg_conf_ctx *ctx) EXPORT_SYMBOL_GPL(blkg_conf_exit); /* - * Similar to blkg_conf_exit, but also unfreezes the queue and releases - * q->elevator_lock. Should be used when blkg_conf_open_bdev_frozen - * is used to open the bdev. + * Similar to blkg_conf_exit, but also unfreezes the queue. Should be used + * when blkg_conf_open_bdev_frozen is used to open the bdev. */ void blkg_conf_exit_frozen(struct blkg_conf_ctx *ctx, unsigned long memflags) { @@ -1012,7 +1008,6 @@ void blkg_conf_exit_frozen(struct blkg_conf_ctx *ctx, unsigned long memflags) struct request_queue *q = ctx->bdev->bd_queue; blkg_conf_exit(ctx); - mutex_unlock(&q->elevator_lock); blk_mq_unfreeze_queue(q, memflags); } } |