From 1d9e9bc6b56e1bb7e33e7e2e1b99d7088356c006 Mon Sep 17 00:00:00 2001
From: Ming Lei <ming.lei@redhat.com>
Date: Tue, 6 Jun 2017 23:22:08 +0800
Subject: [PATCH] blk-mq: don't stop queue for quiescing
Git-commit: 1d9e9bc6b56e1bb7e33e7e2e1b99d7088356c006
Patch-mainline: v4.13-rc1
References: fate#322738,fate#322919,fate#322950,fate#323773
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>
Signed-off-by: Coly Li <colyli@suse.de>
---
block/blk-mq.c | 9 +++------
include/linux/blk-mq.h | 2 --
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);
}
/*
--
2.13.1