From: Halil Pasic pasic@linux.ibm.com
commit f7728002c1c7bfa787b276a31c3ef458739b8e7c upstream.
Commit 780bc7903a32 ("virtio_ring: Support DMA APIs") makes virtqueue_add() return -EIO when we fail to map our I/O buffers. This is a very realistic scenario for guests with encrypted memory, as swiotlb may run out of space, depending on it's size and the I/O load.
The virtio-blk driver interprets -EIO form virtqueue_add() as an IO error, despite the fact that swiotlb full is in absence of bugs a recoverable condition.
Let us change the return code to -ENOMEM, and make the block layer recover form these failures when virtio-blk encounters the condition described above.
Cc: stable@vger.kernel.org Fixes: 780bc7903a32 ("virtio_ring: Support DMA APIs") Signed-off-by: Halil Pasic pasic@linux.ibm.com Tested-by: Michael Mueller mimu@linux.ibm.com Signed-off-by: Michael S. Tsirkin mst@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/virtio/virtio_ring.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
--- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -583,7 +583,7 @@ unmap_release: kfree(desc);
END_USE(vq); - return -EIO; + return -ENOMEM; }
static bool virtqueue_kick_prepare_split(struct virtqueue *_vq) @@ -1085,7 +1085,7 @@ unmap_release: kfree(desc);
END_USE(vq); - return -EIO; + return -ENOMEM; }
static inline int virtqueue_add_packed(struct virtqueue *_vq,