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authorZhang, Yanmin <yanmin_zhang@linux.intel.com>2008-05-22 15:13:29 +0200
committerJens Axboe <jens.axboe@oracle.com>2008-05-28 14:49:27 +0200
commit05caf8dbc1880415df3378cfd114d832c9618b60 (patch)
tree71b2a0839739c4a3e54e7d40d1a2358d61c8b279 /block
parentca39d651d17df49b6d11f851d56c0ce0ce01ea1a (diff)
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>
Diffstat (limited to 'block')
-rw-r--r--block/blk-core.c37
1 files changed, 17 insertions, 20 deletions
diff --git a/block/blk-core.c b/block/blk-core.c
index 6a9cc0d22a61..1905aaba49fb 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -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);
-
- if (!rq) {
- struct io_context *ioc;
+ blk_add_trace_generic(q, bio, rw, BLK_TA_SLEEPRQ);
- blk_add_trace_generic(q, bio, rw, BLK_TA_SLEEPRQ);
-
- __generic_unplug_device(q);
- spin_unlock_irq(q->queue_lock);
- io_schedule();
+ __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);
+ /*
+ * 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;
}