blk-mq: Reduce the number of if-statements in blk_mq_mark_tag_wait()
This patch does not change any functionality but makes the blk_mq_mark_tag_wait() code slightly easier to read. Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Omar Sandoval <osandov@fb.com> Cc: Hannes Reinecke <hare@suse.de> Cc: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
parent
33f782c49a
commit
c27d53fb44
1 changed files with 36 additions and 35 deletions
|
@ -1104,58 +1104,59 @@ static bool blk_mq_mark_tag_wait(struct blk_mq_hw_ctx **hctx,
|
|||
struct request *rq)
|
||||
{
|
||||
struct blk_mq_hw_ctx *this_hctx = *hctx;
|
||||
bool shared_tags = (this_hctx->flags & BLK_MQ_F_TAG_SHARED) != 0;
|
||||
struct sbq_wait_state *ws;
|
||||
wait_queue_entry_t *wait;
|
||||
bool ret;
|
||||
|
||||
if (!shared_tags) {
|
||||
if (!(this_hctx->flags & BLK_MQ_F_TAG_SHARED)) {
|
||||
if (!test_bit(BLK_MQ_S_SCHED_RESTART, &this_hctx->state))
|
||||
set_bit(BLK_MQ_S_SCHED_RESTART, &this_hctx->state);
|
||||
} else {
|
||||
wait = &this_hctx->dispatch_wait;
|
||||
if (!list_empty_careful(&wait->entry))
|
||||
return false;
|
||||
|
||||
spin_lock(&this_hctx->lock);
|
||||
if (!list_empty(&wait->entry)) {
|
||||
spin_unlock(&this_hctx->lock);
|
||||
return false;
|
||||
}
|
||||
|
||||
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.
|
||||
*
|
||||
* Don't clear RESTART here, someone else could have set it.
|
||||
* At most this will cost an extra queue run.
|
||||
*/
|
||||
return blk_mq_get_driver_tag(rq, hctx, false);
|
||||
}
|
||||
|
||||
wait = &this_hctx->dispatch_wait;
|
||||
if (!list_empty_careful(&wait->entry))
|
||||
return false;
|
||||
|
||||
spin_lock(&this_hctx->lock);
|
||||
if (!list_empty(&wait->entry)) {
|
||||
spin_unlock(&this_hctx->lock);
|
||||
return false;
|
||||
}
|
||||
|
||||
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.
|
||||
*/
|
||||
return ret;
|
||||
} else {
|
||||
if (!ret) {
|
||||
spin_unlock(&this_hctx->lock);
|
||||
return false;
|
||||
}
|
||||
|
||||
/*
|
||||
* 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);
|
||||
if (!ret) {
|
||||
spin_unlock(&this_hctx->lock);
|
||||
return true;
|
||||
return false;
|
||||
}
|
||||
|
||||
/*
|
||||
* 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;
|
||||
}
|
||||
|
||||
bool blk_mq_dispatch_rq_list(struct request_queue *q, struct list_head *list,
|
||||
|
|
Loading…
Reference in a new issue