Enforce a minimum SG_IO timeout

There's no point in having too short SG_IO timeouts, since if the
command does end up timing out, we'll end up through the reset sequence
that is several seconds long in order to abort the command that timed
out.

As a result, shorter timeouts than a few seconds simply do not make
sense, as the recovery would be longer than the timeout itself.

Add a BLK_MIN_SG_TIMEOUT to match the existign BLK_DEFAULT_SG_TIMEOUT.

Suggested-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Acked-by: Tejun Heo <tj@kernel.org>
Acked-by: Jens Axboe <jens.axboe@oracle.com>
Cc: Jeff Garzik <jeff@garzik.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Linus Torvalds 2008-12-05 14:49:18 -08:00
parent 24920a79a2
commit f2f1fa78a1
3 changed files with 5 additions and 0 deletions

View File

@ -202,6 +202,8 @@ static int blk_fill_sgv4_hdr_rq(struct request_queue *q, struct request *rq,
rq->timeout = q->sg_timeout;
if (!rq->timeout)
rq->timeout = BLK_DEFAULT_SG_TIMEOUT;
if (rq->timeout < BLK_MIN_SG_TIMEOUT)
rq->timeout = BLK_MIN_SG_TIMEOUT;
return 0;
}

View File

@ -208,6 +208,8 @@ static int blk_fill_sghdr_rq(struct request_queue *q, struct request *rq,
rq->timeout = q->sg_timeout;
if (!rq->timeout)
rq->timeout = BLK_DEFAULT_SG_TIMEOUT;
if (rq->timeout < BLK_MIN_SG_TIMEOUT)
rq->timeout = BLK_MIN_SG_TIMEOUT;
return 0;
}

View File

@ -662,6 +662,7 @@ extern unsigned long blk_max_low_pfn, blk_max_pfn;
* default timeout for SG_IO if none specified
*/
#define BLK_DEFAULT_SG_TIMEOUT (60 * HZ)
#define BLK_MIN_SG_TIMEOUT (7 * HZ)
#ifdef CONFIG_BOUNCE
extern int init_emergency_isa_pool(void);