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authorMing Lei <ming.lei@redhat.com>2017-06-06 23:22:08 +0800
committerJens Axboe <axboe@kernel.dk>2017-06-18 14:24:48 -0600
commit1d9e9bc6b56e1bb7e33e7e2e1b99d7088356c006 (patch)
tree4a0929fa4e384718aabcc2180399b219f18f1615
parent69e07c4adb8669fd77f3b59abdb436aca9f1bee9 (diff)
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blk-mq: don't stop queue for quiescing
Queue can be started by other blk-mq APIs and can be used in different cases, this limits uses of blk_mq_quiesce_queue() if it is based on stopping queue, and make its usage very difficult, especially users have to use the stop queue APIs carefully for avoiding to break blk_mq_quiesce_queue(). We have applied the QUIESCED flag for draining and blocking dispatch, so it isn't necessary to stop queue any more. After stopping queue is removed, blk_mq_quiesce_queue() can be used safely and easily, then users won't worry about queue restarting during quiescing at all. Reviewed-by: Bart Van Assche <Bart.VanAssche@sandisk.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
-rw-r--r--block/blk-mq.c9
-rw-r--r--include/linux/blk-mq.h2
2 files changed, 3 insertions, 8 deletions
diff --git a/block/blk-mq.c b/block/blk-mq.c
index f2a73190f60d..dbae586602f6 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -169,11 +169,7 @@ void blk_mq_quiesce_queue(struct request_queue *q)
unsigned int i;
bool rcu = false;
- __blk_mq_stop_hw_queues(q, true);
-
- spin_lock_irq(q->queue_lock);
- queue_flag_set(QUEUE_FLAG_QUIESCED, q);
- spin_unlock_irq(q->queue_lock);
+ blk_mq_quiesce_queue_nowait(q);
queue_for_each_hw_ctx(q, hctx, i) {
if (hctx->flags & BLK_MQ_F_BLOCKING)
@@ -199,7 +195,8 @@ void blk_mq_unquiesce_queue(struct request_queue *q)
queue_flag_clear(QUEUE_FLAG_QUIESCED, q);
spin_unlock_irq(q->queue_lock);
- blk_mq_start_stopped_hw_queues(q, true);
+ /* dispatch requests which are inserted during quiescing */
+ blk_mq_run_hw_queues(q, true);
}
EXPORT_SYMBOL_GPL(blk_mq_unquiesce_queue);
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index de6536c14ae7..f1bd13ae8f57 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -271,8 +271,6 @@ static inline void blk_mq_quiesce_queue_nowait(struct request_queue *q)
spin_lock_irq(q->queue_lock);
queue_flag_set(QUEUE_FLAG_QUIESCED, q);
spin_unlock_irq(q->queue_lock);
-
- blk_mq_stop_hw_queues(q);
}
/*