@@ -867,11 +867,12 @@ static int virtblk_probe(struct virtio_device *vdev)
blk_queue_io_opt(q, blk_size * opt_io_size);
if (virtio_has_feature(vdev, VIRTIO_BLK_F_DISCARD)) {
- q->limits.discard_granularity = blk_size;
-
virtio_cread(vdev, struct virtio_blk_config,
discard_sector_alignment, &v);
- q->limits.discard_alignment = v ? v << SECTOR_SHIFT : 0;
+ if (v)
+ q->limits.discard_granularity = v << SECTOR_SHIFT;
+ else
+ q->limits.discard_granularity = blk_size;
virtio_cread(vdev, struct virtio_blk_config,
max_discard_sectors, &v);
The discard_alignment queue limit is named a bit misleading means the offset into the block device at which the discard granularity starts. On the other hand the discard_sector_alignment from the virtio 1.1 looks similar to what Linux uses as discard granularity (even if not very well described): "discard_sector_alignment can be used by OS when splitting a request based on alignment. " And at least qemu does set it to the discard granularity. So stop setting the discard_alignment and use the virtio discard_sector_alignment to set the discard granularity. Fixes: 1f23816b8eb8 ("virtio_blk: add discard and write zeroes support") Signed-off-by: Christoph Hellwig <hch@lst.de> --- drivers/block/virtio_blk.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-)