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authorRichard Kennedy2010-04-14 13:54:03 -0500
committerJens Axboe2010-04-21 10:42:08 -0500
commita534dbe96e9929c7245924d8252d89048c23d569 (patch)
tree394151a29dc2ea43e20cbf5b605732525ce09d9d /block/blk-timeout.c
parent05ce7bfe547c9fa967d9cab6c37867a9cb6fb3fa (diff)
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block: ensure jiffies wrap is handled correctly in blk_rq_timed_out_timer
blk_rq_timed_out_timer() relied on blk_add_timer() never returning a timer value of zero, but commit 7838c15b8dd18e78a523513749e5b54bda07b0cb 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> Cc: stable@kernel.org Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to 'block/blk-timeout.c')
-rw-r--r--block/blk-timeout.c12
1 files changed, 5 insertions, 7 deletions
diff --git a/block/blk-timeout.c b/block/blk-timeout.c
index 1ba7e0aca87..4f0c06c7a33 100644
--- a/block/blk-timeout.c
+++ b/block/blk-timeout.c
@@ -109,6 +109,7 @@ void blk_rq_timed_out_timer(unsigned long data)
109 struct request_queue *q = (struct request_queue *) data; 109 struct request_queue *q = (struct request_queue *) data;
110 unsigned long flags, next = 0; 110 unsigned long flags, next = 0;
111 struct request *rq, *tmp; 111 struct request *rq, *tmp;
112 int next_set = 0;
112 113
113 spin_lock_irqsave(q->queue_lock, flags); 114 spin_lock_irqsave(q->queue_lock, flags);
114 115
@@ -122,16 +123,13 @@ void blk_rq_timed_out_timer(unsigned long data)
122 if (blk_mark_rq_complete(rq)) 123 if (blk_mark_rq_complete(rq))
123 continue; 124 continue;
124 blk_rq_timed_out(rq); 125 blk_rq_timed_out(rq);
125 } else if (!next || time_after(next, rq->deadline)) 126 } else if (!next_set || time_after(next, rq->deadline)) {
126 next = rq->deadline; 127 next = rq->deadline;
128 next_set = 1;
129 }
127 } 130 }
128 131
129 /* 132 if (next_set)
130 * next can never be 0 here with the list non-empty, since we always
131 * bump ->deadline to 1 so we can detect if the timer was ever added
132 * or not. See comment in blk_add_timer()
133 */
134 if (next)
135 mod_timer(&q->timeout, round_jiffies_up(next)); 133 mod_timer(&q->timeout, round_jiffies_up(next));
136 134
137 spin_unlock_irqrestore(q->queue_lock, flags); 135 spin_unlock_irqrestore(q->queue_lock, flags);