Hi,
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.
Please pull!
git://git.kernel.dk/linux-block.git for-linus
virtio_blk: fix race between start and stop queue (2014-05-27 08:41:10 -0600)
----------------------------------------------------------------
Ming Lei (1):
virtio_blk: fix race between start and stop queue
drivers/block/virtio_blk.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index 6d8a87f252de..cb9b1f8326c3 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -144,11 +144,11 @@ static void virtblk_done(struct virtqueue *vq)
if (unlikely(virtqueue_is_broken(vq)))
break;
} while (!virtqueue_enable_cb(vq));
- spin_unlock_irqrestore(&vblk->vq_lock, flags);
/* In case queue is stopped waiting for more buffers. */
if (req_done)
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)
@@ -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);
if (err) {
virtqueue_kick(vblk->vq);
- spin_unlock_irqrestore(&vblk->vq_lock, flags);
blk_mq_stop_hw_queue(hctx);
+ spin_unlock_irqrestore(&vblk->vq_lock, flags);
/* Out of mem doesn't actually happen, since we fall back
* to direct descriptors */
if (err == -ENOMEM || err == -ENOSPC)
--
Jens Axboe
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
