[PATCH V4 1/2] blk-mq: set RQF_MQ_TIMEOUT_EXPIRED when the rq's timeout isn't handled

[Ming Lei <ming.lei@redhat.com>]

Firstly blk_mq_timeout_work() is always run exclusivley for each queue.

Secondly if .timeout() returns BLK_EH_RESET_TIMER or BLK_EH_HANDLED,
the flag of RQF_MQ_TIMEOUT_EXPIRED will be cleared for this request,
because the request will be requeued or freed for BLK_EH_HANDLED, and
for BLK_EH_RESET_TIMER, new timer has to be started for this req.

So this patch only sets the flag of RQF_MQ_TIMEOUT_EXPIRED when .timeout
returns neither BLK_EH_RESET_TIMER nor BLK_EH_HANDLED.

Cc: "jianchao.wang" <jianchao.w.wang@oracle.com>
Cc: Bart Van Assche <bart.vanassche@wdc.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Sagi Grimberg <sagi@grimberg.me>
Cc: Israel Rukshin <israelr@mellanox.com>,
Cc: Max Gurtovoy <maxg@mellanox.com>
Cc: Martin Steigerwald <Martin@Lichtvoll.de>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
---
 block/blk-mq.c      | 4 ++--
 block/blk-timeout.c | 1 -
 2 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 0dc9e341c2a7..d6a21898933d 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -815,8 +815,6 @@ static void blk_mq_rq_timed_out(struct request *req, bool reserved)
 	const struct blk_mq_ops *ops = req->q->mq_ops;
 	enum blk_eh_timer_return ret = BLK_EH_RESET_TIMER;
 
-	req->rq_flags |= RQF_MQ_TIMEOUT_EXPIRED;
-
 	if (ops->timeout)
 		ret = ops->timeout(req, reserved);
 
@@ -834,9 +832,11 @@ static void blk_mq_rq_timed_out(struct request *req, bool reserved)
 		blk_add_timer(req);
 		break;
 	case BLK_EH_NOT_HANDLED:
+		req->rq_flags |= RQF_MQ_TIMEOUT_EXPIRED;
 		break;
 	default:
 		printk(KERN_ERR "block: bad eh return: %d\n", ret);
+		req->rq_flags |= RQF_MQ_TIMEOUT_EXPIRED;
 		break;
 	}
 }
diff --git a/block/blk-timeout.c b/block/blk-timeout.c
index 652d4d4d3e97..f95d6e6cbc96 100644
--- a/block/blk-timeout.c
+++ b/block/blk-timeout.c
@@ -214,7 +214,6 @@ void blk_add_timer(struct request *req)
 		req->timeout = q->rq_timeout;
 
 	blk_rq_set_deadline(req, jiffies + req->timeout);
-	req->rq_flags &= ~RQF_MQ_TIMEOUT_EXPIRED;
 
 	/*
 	 * Only the non-mq case needs to add the request to a protected list.
-- 
2.9.5