cfq-iosched: simplify control flow in cfq_get_queue()
cfq_get_queue()'s control flow looks like the following.
async_cfqq = NULL;
cfqq = NULL;
if (!is_sync) {
...
async_cfqq = ...;
cfqq = *async_cfqq;
}
if (!cfqq)
cfqq = ...;
if (!is_sync && !(*async_cfqq))
...;
The only thing the local variable init, the second if, and the
async_cfqq test in the third if achieves is to skip cfqq creation and
installation if *async_cfqq was already non-NULL. This is needlessly
complicated with different tests examining the same condition.
Simplify it to the following.
if (!is_sync) {
...
async_cfqq = ...;
cfqq = *async_cfqq;
if (cfqq)
goto out;
}
cfqq = ...;
if (!is_sync)
...;
out:
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Jeff Moyer <jmoyer@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Arianna Avanzini <avanzini.arianna@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index c62bb2e..e91093d 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -3731,8 +3731,8 @@
{
int ioprio_class = IOPRIO_PRIO_CLASS(cic->ioprio);
int ioprio = IOPRIO_PRIO_DATA(cic->ioprio);
- struct cfq_queue **async_cfqq = NULL;
- struct cfq_queue *cfqq = NULL;
+ struct cfq_queue **async_cfqq;
+ struct cfq_queue *cfqq;
if (!is_sync) {
if (!ioprio_valid(cic->ioprio)) {
@@ -3742,19 +3742,20 @@
}
async_cfqq = cfq_async_queue_prio(cfqd, ioprio_class, ioprio);
cfqq = *async_cfqq;
+ if (cfqq)
+ goto out;
}
- if (!cfqq)
- cfqq = cfq_find_alloc_queue(cfqd, is_sync, cic, bio, gfp_mask);
+ cfqq = cfq_find_alloc_queue(cfqd, is_sync, cic, bio, gfp_mask);
/*
* pin the queue now that it's allocated, scheduler exit will prune it
*/
- if (!is_sync && !(*async_cfqq)) {
+ if (!is_sync) {
cfqq->ref++;
*async_cfqq = cfqq;
}
-
+out:
cfqq->ref++;
return cfqq;
}