The patch below does not apply to the 4.9-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@xxxxxxxxxxxxxxx>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From f7728002c1c7bfa787b276a31c3ef458739b8e7c Mon Sep 17 00:00:00 2001
From: Halil Pasic <pasic@xxxxxxxxxxxxx>
Date: Thu, 14 Nov 2019 13:46:46 +0100
Subject: [PATCH] virtio_ring: fix return code on DMA mapping fails
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@xxxxxxxxxxxxxxx
Fixes: 780bc7903a32 ("virtio_ring: Support DMA APIs")
Signed-off-by: Halil Pasic <pasic@xxxxxxxxxxxxx>
Tested-by: Michael Mueller <mimu@xxxxxxxxxxxxx>
Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index a8041e451e9e..867c7ebd3f10 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -583,7 +583,7 @@ static inline int virtqueue_add_split(struct virtqueue *_vq,
kfree(desc);
END_USE(vq);
- return -EIO;
+ return -ENOMEM;
}
static bool virtqueue_kick_prepare_split(struct virtqueue *_vq)
@@ -1085,7 +1085,7 @@ static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq,
kfree(desc);
END_USE(vq);
- return -EIO;
+ return -ENOMEM;
}
static inline int virtqueue_add_packed(struct virtqueue *_vq,
