block: ensure jiffies wrap is handled correctly in blk_rq_timed_out_timer (c0d97e9c) · Commits · 戴 / test

blk_rq_timed_out_timer() relied on blk_add_timer() never returning a timer value of zero, but commit removed the code that bumped this value when it was zero. Therefore when jiffies is near wrap we could get unlucky & not set the timeout value correctly. This patch uses a flag to indicate that the timeout value was set and so handles jiffies wrap correctly, and it keeps all the logic in one function so should be easier to maintain in the future. Signed-off-by:

Richard Kennedy <richard@rsk.demon.co.uk> Signed-off-by:

Jens Axboe <jens.axboe@oracle.com>

block/blk-timeout.c

+5 −7

Original line number	Diff line number	Diff line
		@@ -109,6 +109,7 @@ void blk_rq_timed_out_timer(unsigned long data)
		struct request_queue q = (struct request_queue ) data;
		unsigned long flags, next = 0;
		struct request rq, tmp;
		int next_set = 0;

		spin_lock_irqsave(q->queue_lock, flags);

		@@ -122,16 +123,13 @@ void blk_rq_timed_out_timer(unsigned long data)
		if (blk_mark_rq_complete(rq))
		continue;
		blk_rq_timed_out(rq);
		} else if (!next \|\| time_after(next, rq->deadline))
		} else if (!next_set \|\| time_after(next, rq->deadline)) {
		next = rq->deadline;
		next_set = 1;
		}
		}

		/*
		* next can never be 0 here with the list non-empty, since we always
		* bump ->deadline to 1 so we can detect if the timer was ever added
		* or not. See comment in blk_add_timer()
		*/
		if (next)
		if (next_set)
		mod_timer(&q->timeout, round_jiffies_up(next));

		spin_unlock_irqrestore(q->queue_lock, flags);

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