diff options
| -rw-r--r-- | block/blk-mq.c | 69 |
1 files changed, 35 insertions, 34 deletions
diff --git a/block/blk-mq.c b/block/blk-mq.c index 8000ba6db07d..afccd0848d6f 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -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; - } + /* + * 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; - ws = bt_wait_ptr(&this_hctx->tags->bitmap_tags, this_hctx); - add_wait_queue(&ws->wait, wait); + 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, |