diff options
| author | Xie Yongji <xieyongji@bytedance.com> | 2022-03-04 18:00:57 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-03-16 13:21:45 +0100 |
| commit | 45d470e4f80825a76f2a30e986c769ac7de2c5c6 (patch) | |
| tree | 21e14534c39ffffb40b356d7e19a2f1422acdca3 /drivers/block | |
| parent | 278b2c7d9fe535a876e1f735166d4d3eb22f8273 (diff) | |
virtio-blk: Don't use MAX_DISCARD_SEGMENTS if max_discard_seg is zero
[ Upstream commit dacc73ed0b88f1a787ec20385f42ca9dd9eddcd0 ]
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'drivers/block')
| -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 816eb2db7308..4b3645e648ee 100644 --- a/drivers/block/virtio_blk.c +++ b/drivers/block/virtio_blk.c @@ -980,9 +980,15 @@ 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); } |