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Commit cd79bde2 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'for-linus' of git://git.kernel.dk/linux-block 

Pull virtio_blk fix from Jens Axboe:
 "There's a start/stop queue race in virtio_blk, which causes stalls and
  erratic behaviour for some.  I've had this queued up for 3.16 for a
  while, but I think we should push it into the current series as well.

  So I cherry picked the commit and added a stable marker as well, so it
  can propagate down"

* 'for-linus' of git://git.kernel.dk/linux-block:
  virtio_blk: fix race between start and stop queue
parents aa699a1d aa0818c6

drivers/block/virtio_blk.c

+2 −2
Original line number Original line Diff line number Diff line
@@ -144,11 +144,11 @@ static void virtblk_done(struct virtqueue *vq) 
		if (unlikely(virtqueue_is_broken(vq)))

		if (unlikely(virtqueue_is_broken(vq)))

			break;

			break;

	} while (!virtqueue_enable_cb(vq));

	} while (!virtqueue_enable_cb(vq));

	spin_unlock_irqrestore(&vblk->vq_lock, flags);





	/* In case queue is stopped waiting for more buffers. */

	/* In case queue is stopped waiting for more buffers. */

	if (req_done)

	if (req_done)

		blk_mq_start_stopped_hw_queues(vblk->disk->queue);

		blk_mq_start_stopped_hw_queues(vblk->disk->queue);

	spin_unlock_irqrestore(&vblk->vq_lock, flags);

}

}





static int virtio_queue_rq(struct blk_mq_hw_ctx *hctx, struct request *req)

static int virtio_queue_rq(struct blk_mq_hw_ctx *hctx, struct request *req)
@@ -202,8 +202,8 @@ static int virtio_queue_rq(struct blk_mq_hw_ctx *hctx, struct request *req) 
	err = __virtblk_add_req(vblk->vq, vbr, vbr->sg, num);

	err = __virtblk_add_req(vblk->vq, vbr, vbr->sg, num);

	if (err) {

	if (err) {

		virtqueue_kick(vblk->vq);

		virtqueue_kick(vblk->vq);

		spin_unlock_irqrestore(&vblk->vq_lock, flags);

		blk_mq_stop_hw_queue(hctx);

		blk_mq_stop_hw_queue(hctx);

		spin_unlock_irqrestore(&vblk->vq_lock, flags);

		/* Out of mem doesn't actually happen, since we fall back

		/* Out of mem doesn't actually happen, since we fall back

		 * to direct descriptors */

		 * to direct descriptors */

		if (err == -ENOMEM || err == -ENOSPC)

		if (err == -ENOMEM || err == -ENOSPC)