From: Tejun Heo <t...@kernel.org>
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 <t...@kernel.org>
Acked-by: Jeff Moyer <jmo...@redhat.com>
Cc: Vivek Goyal <vgo...@redhat.com>
Cc: Arianna Avanzini <avanzini.aria...@gmail.com>
Signed-off-by: Jens Axboe <ax...@fb.com>
https://jira.sw.ru/browse/PSBM-41334
(cherry picked from commit 4ebc1c61d6185604c97fd0b0355ab668052044ab)
Signed-off-by: Andrey Ryabinin <aryabi...@virtuozzo.com>
---
block/cfq-iosched.c | 13 +++++++------
1 file changed, 7 insertions(+), 6 deletions(-)
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 987c0f9..a4149c3 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -3696,25 +3696,26 @@ cfq_get_queue(struct cfq_data *cfqd, bool is_sync,
struct cfq_io_cq *cic,
{
const int ioprio_class = IOPRIO_PRIO_CLASS(cic->ioprio);
const 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) {
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);
+ cfqq = cfq_find_alloc_queue(cfqd, is_sync, cic, bio);
/*
* 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;
}
--
2.4.10
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