null_blk: use async queue restart helper

If null_blk is run in NULL_IRQ_TIMER mode and with queue_mode NULL_Q_RQ,
we need to restart the queue from the hrtimer interrupt. We can't
directly invoke the request_fn from that context, so punt the queue run
to async kblockd context.

Tested-by: Rabin Vincent <rabin@rab.in>
Signed-off-by: Jens Axboe <axboe@fb.com>

diff --git a/drivers/block/null_blk.c b/drivers/block/null_blk.c
index a428e4e..09e3c0d 100644 (file)
--- a/drivers/block/null_blk.c
+++ b/drivers/block/null_blk.c
@@ -232,20 +232,19 @@ static void end_cmd(struct nullb_cmd *cmd)
                break;
        case NULL_Q_BIO:
                bio_endio(cmd->bio);
-               goto free_cmd;
+               break;
        }
 
+       free_cmd(cmd);
+
        /* Restart queue if needed, as we are freeing a tag */
-       if (q && !q->mq_ops && blk_queue_stopped(q)) {
+       if (queue_mode == NULL_Q_RQ && blk_queue_stopped(q)) {
                unsigned long flags;
 
                spin_lock_irqsave(q->queue_lock, flags);
-               if (blk_queue_stopped(q))
-                       blk_start_queue(q);
+               blk_start_queue_async(q);
                spin_unlock_irqrestore(q->queue_lock, flags);
        }
-free_cmd:
-       free_cmd(cmd);
 }
 
 static enum hrtimer_restart null_cmd_timer_expired(struct hrtimer *timer)