diff options
| author | Christoph Hellwig <hch@lst.de> | 2010-05-25 14:17:54 +0200 |
|---|---|---|
| committer | Rusty Russell <rusty@rustcorp.com.au> | 2010-06-03 22:39:18 +0930 |
| commit | a5b365a652206ca300256974ed9301a7d241a6ed (patch) | |
| tree | 1898846dcce5b1815f8e13d7b0b610c83be1da7f | |
| parent | aef4b9aaae1decc775778903922bd0075cce7a88 (diff) | |
virtio-blk: fix minimum number of S/G elements
We need at least one S/G element to operate properly, as does the block
layer which increments it to one anyway. We hit this due to a qemu
bug which advertises a sg_elements of 0 under some circumstances.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (tweaked logic)
| -rw-r--r-- | drivers/block/virtio_blk.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c index 83fa09a836c..258bc2ae288 100644 --- a/drivers/block/virtio_blk.c +++ b/drivers/block/virtio_blk.c @@ -298,7 +298,9 @@ static int __devinit virtblk_probe(struct virtio_device *vdev) err = virtio_config_val(vdev, VIRTIO_BLK_F_SEG_MAX, offsetof(struct virtio_blk_config, seg_max), &sg_elems); - if (err) + + /* We need at least one SG element, whatever they say. */ + if (err || !sg_elems) sg_elems = 1; /* We need an extra sg elements at head and tail. */ |