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| author | Ming Lei <tom.leiming@gmail.com> | 2017-03-27 20:06:58 +0800 |
|---|---|---|
| committer | Jens Axboe <axboe@fb.com> | 2017-03-29 08:03:42 -0600 |
| commit | d3cfb2a0ac0b8487d28a1ee207c29617bf6e6820 (patch) | |
| tree | 85c3948ceda4296641bebd97fe1fbd177481a14d | |
| parent | 1671d522cdd9933dee7dddfcf9f62c561283824a (diff) | |
| download | linux-d3cfb2a0ac0b8487d28a1ee207c29617bf6e6820.tar.bz2 | |
block: block new I/O just after queue is set as dying
Before commit 780db2071a(blk-mq: decouble blk-mq freezing
from generic bypassing), the dying flag is checked before
entering queue, and Tejun converts the checking into .mq_freeze_depth,
and assumes the counter is increased just after dying flag
is set. Unfortunately we doesn't do that in blk_set_queue_dying().
This patch calls blk_freeze_queue_start() in blk_set_queue_dying(),
so that we can block new I/O coming once the queue is set as dying.
Given blk_set_queue_dying() is always called in remove path
of block device, and queue will be cleaned up later, we don't
need to worry about undoing the counter.
Cc: Tejun Heo <tj@kernel.org>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
| -rw-r--r-- | block/blk-core.c | 13 |
1 files changed, 10 insertions, 3 deletions
diff --git a/block/blk-core.c b/block/blk-core.c index 7b66f76f9cff..43b7d06ced69 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -500,6 +500,13 @@ void blk_set_queue_dying(struct request_queue *q) queue_flag_set(QUEUE_FLAG_DYING, q); spin_unlock_irq(q->queue_lock); + /* + * When queue DYING flag is set, we need to block new req + * entering queue, so we call blk_freeze_queue_start() to + * prevent I/O from crossing blk_queue_enter(). + */ + blk_freeze_queue_start(q); + if (q->mq_ops) blk_mq_wake_waiters(q); else { @@ -672,9 +679,9 @@ int blk_queue_enter(struct request_queue *q, bool nowait) /* * read pair of barrier in blk_freeze_queue_start(), * we need to order reading __PERCPU_REF_DEAD flag of - * .q_usage_counter and reading .mq_freeze_depth, - * otherwise the following wait may never return if the - * two reads are reordered. + * .q_usage_counter and reading .mq_freeze_depth or + * queue dying flag, otherwise the following wait may + * never return if the two reads are reordered. */ smp_rmb(); |