block: Move the second call to get_request to the end of the loop

In function get_request_wait, the second call to get_request could be
moved to the end of the while loop, because if the first call to
get_request fails, the second call will fail without sleep.

Signed-off-by: Zhang Yanmin <yanmin.zhang@intel.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
This commit is contained in:
Zhang, Yanmin 2008-05-22 15:13:29 +02:00 committed by Jens Axboe
parent ca39d651d1
commit 05caf8dbc1

View file

@ -806,35 +806,32 @@ static struct request *get_request_wait(struct request_queue *q, int rw_flags,
rq = get_request(q, rw_flags, bio, GFP_NOIO);
while (!rq) {
DEFINE_WAIT(wait);
struct io_context *ioc;
struct request_list *rl = &q->rq;
prepare_to_wait_exclusive(&rl->wait[rw], &wait,
TASK_UNINTERRUPTIBLE);
rq = get_request(q, rw_flags, bio, GFP_NOIO);
blk_add_trace_generic(q, bio, rw, BLK_TA_SLEEPRQ);
if (!rq) {
struct io_context *ioc;
__generic_unplug_device(q);
spin_unlock_irq(q->queue_lock);
io_schedule();
blk_add_trace_generic(q, bio, rw, BLK_TA_SLEEPRQ);
/*
* After sleeping, we become a "batching" process and
* will be able to allocate at least one request, and
* up to a big batch of them for a small period time.
* See ioc_batching, ioc_set_batching
*/
ioc = current_io_context(GFP_NOIO, q->node);
ioc_set_batching(q, ioc);
__generic_unplug_device(q);
spin_unlock_irq(q->queue_lock);
io_schedule();
/*
* After sleeping, we become a "batching" process and
* will be able to allocate at least one request, and
* up to a big batch of them for a small period time.
* See ioc_batching, ioc_set_batching
*/
ioc = current_io_context(GFP_NOIO, q->node);
ioc_set_batching(q, ioc);
spin_lock_irq(q->queue_lock);
}
spin_lock_irq(q->queue_lock);
finish_wait(&rl->wait[rw], &wait);
}
rq = get_request(q, rw_flags, bio, GFP_NOIO);
};
return rq;
}