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authorHalil Pasic <pasic@linux.ibm.com>2020-02-13 13:37:27 +0100
committerMichael S. Tsirkin <mst@redhat.com>2020-03-08 05:35:24 -0400
commitf5f6b95c72f7f8bb46eace8c5306c752d0133daa (patch)
treebee578f0cdc2d74c420259a8b362dcb6ad17dc20 /drivers/block
parentf13f09a12cbd0c7b776e083c5d008b6c6a9c4e0b (diff)
virtio-blk: fix hw_queue stopped on arbitrary error
Since nobody else is going to restart our hw_queue for us, the blk_mq_start_stopped_hw_queues() is in virtblk_done() is not sufficient necessarily sufficient to ensure that the queue will get started again. In case of global resource outage (-ENOMEM because mapping failure, because of swiotlb full) our virtqueue may be empty and we can get stuck with a stopped hw_queue. Let us not stop the queue on arbitrary errors, but only on -EONSPC which indicates a full virtqueue, where the hw_queue is guaranteed to get started by virtblk_done() before when it makes sense to carry on submitting requests. Let us also remove a stale comment. Signed-off-by: Halil Pasic <pasic@linux.ibm.com> Cc: Jens Axboe <axboe@kernel.dk> Fixes: f7728002c1c7 ("virtio_ring: fix return code on DMA mapping fails") Link: https://lore.kernel.org/r/20200213123728.61216-2-pasic@linux.ibm.com Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Diffstat (limited to 'drivers/block')
-rw-r--r--drivers/block/virtio_blk.c8
1 files changed, 5 insertions, 3 deletions
diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index 54158766334b..adfe43f5ffe4 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -245,10 +245,12 @@ static blk_status_t virtio_queue_rq(struct blk_mq_hw_ctx *hctx,
err = virtblk_add_req(vblk->vqs[qid].vq, vbr, vbr->sg, num);
if (err) {
virtqueue_kick(vblk->vqs[qid].vq);
- blk_mq_stop_hw_queue(hctx);
+ /* Don't stop the queue if -ENOMEM: we may have failed to
+ * bounce the buffer due to global resource outage.
+ */
+ if (err == -ENOSPC)
+ blk_mq_stop_hw_queue(hctx);
spin_unlock_irqrestore(&vblk->vqs[qid].lock, flags);
- /* Out of mem doesn't actually happen, since we fall back
- * to direct descriptors */
if (err == -ENOMEM || err == -ENOSPC)
return BLK_STS_DEV_RESOURCE;
return BLK_STS_IOERR;