Reduce the number of return statements from three to one. Reduce the
number of spin_unlock(&this_hctx->lock) calls from two to one. Fix
a misleading comment: since blk-mq-tag.c always uses wake_up_all()
other waiters are woken up whether or not the current hctx is removed
from the wait list. This patch does not change any functionality.
Signed-off-by: Bart Van Assche <bart.vanassche@xxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Omar Sandoval <osandov@xxxxxx>
Cc: Hannes Reinecke <hare@xxxxxxx>
Cc: Johannes Thumshirn <jthumshirn@xxxxxxx>
---
block/blk-mq.c | 41 +++++++++++++++--------------------------
1 file changed, 15 insertions(+), 26 deletions(-)
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 7f290a91a612..26fec4dfa40f 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1039,6 +1039,11 @@ static bool blk_mq_mark_tag_wait(struct blk_mq_hw_ctx **hctx,
if (!shared_tags) {
if (!test_bit(BLK_MQ_S_SCHED_RESTART, &this_hctx->state))
set_bit(BLK_MQ_S_SCHED_RESTART, &this_hctx->state);
+ ret = blk_mq_get_driver_tag(rq, hctx, false);
+ /*
+ * Don't clear RESTART here, someone else could have set it.
+ * At most this will cost an extra queue run.
+ */
} else {
wait = &this_hctx->dispatch_wait;
if (!list_empty_careful(&wait->entry))
@@ -1052,37 +1057,21 @@ static bool blk_mq_mark_tag_wait(struct blk_mq_hw_ctx **hctx,
ws = bt_wait_ptr(&this_hctx->tags->bitmap_tags, this_hctx);
add_wait_queue(&ws->wait, wait);
- }
-
- /*
- * It's possible that a tag was freed in the window between the
- * allocation failure and adding the hardware queue to the wait
- * queue.
- */
- ret = blk_mq_get_driver_tag(rq, hctx, false);
-
- if (!shared_tags) {
/*
- * Don't clear RESTART here, someone else could have set it.
- * At most this will cost an extra queue run.
+ * It's possible that a tag was freed in the window between the
+ * allocation failure and adding the hardware queue to the wait
+ * queue.
*/
- return ret;
- } else {
- if (!ret) {
- spin_unlock(&this_hctx->lock);
- return false;
+ ret = blk_mq_get_driver_tag(rq, hctx, false);
+ /* If we got a tag remove ourselves from the wait queue. */
+ if (ret) {
+ spin_lock_irq(&ws->wait.lock);
+ list_del_init(&wait->entry);
+ spin_unlock_irq(&ws->wait.lock);
}
-
- /*
- * We got a tag, remove ourselves from the wait queue to ensure
- * someone else gets the wakeup.
- */
- spin_lock_irq(&ws->wait.lock);
- list_del_init(&wait->entry);
- spin_unlock_irq(&ws->wait.lock);
spin_unlock(&this_hctx->lock);
- return true;
}
+ return ret;
}
bool blk_mq_dispatch_rq_list(struct request_queue *q, struct list_head *list,
--
2.15.0
