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| author | Xie Yongji <xieyongji@bytedance.com> | 2022-03-04 13:00:57 +0300 |
|---|---|---|
| committer | Michael S. Tsirkin <mst@redhat.com> | 2022-03-06 14:06:50 +0300 |
| commit | dacc73ed0b88f1a787ec20385f42ca9dd9eddcd0 (patch) | |
| tree | ee6fb4913ad18aebc267b078fba42747c181db02 | |
| parent | e2ae38cf3d91837a493cb2093c87700ff3cbe667 (diff) | |
| download | linux-dacc73ed0b88f1a787ec20385f42ca9dd9eddcd0.tar.xz | |
virtio-blk: Don't use MAX_DISCARD_SEGMENTS if max_discard_seg is zero
Currently the value of max_discard_segment will be set to
MAX_DISCARD_SEGMENTS (256) with no basis in hardware if device
set 0 to max_discard_seg in configuration space. It's incorrect
since the device might not be able to handle such large descriptors.
To fix it, let's follow max_segments restrictions in this case.
Fixes: 1f23816b8eb8 ("virtio_blk: add discard and write zeroes support")
Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
Link: https://lore.kernel.org/r/20220304100058.116-1-xieyongji@bytedance.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
| -rw-r--r-- | drivers/block/virtio_blk.c | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c index c443cd64fc9b..7fc2c8b97077 100644 --- a/drivers/block/virtio_blk.c +++ b/drivers/block/virtio_blk.c @@ -925,9 +925,15 @@ static int virtblk_probe(struct virtio_device *vdev) virtio_cread(vdev, struct virtio_blk_config, max_discard_seg, &v); + + /* + * max_discard_seg == 0 is out of spec but we always + * handled it. + */ + if (!v) + v = sg_elems - 2; blk_queue_max_discard_segments(q, - min_not_zero(v, - MAX_DISCARD_SEGMENTS)); + min(v, MAX_DISCARD_SEGMENTS)); blk_queue_flag_set(QUEUE_FLAG_DISCARD, q); } |