From: Christoph Hellwig hch@lst.de
[ Upstream commit 62952cc5bccd89b76d710de1d0b43244af0f2903 ]
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 Reviewed-by: Martin K. Petersen martin.petersen@oracle.com Link: https://lore.kernel.org/r/20220418045314.360785-5-hch@lst.de Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/block/virtio_blk.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c index 02e2056780ad..9b54eec9b17e 100644 --- a/drivers/block/virtio_blk.c +++ b/drivers/block/virtio_blk.c @@ -865,11 +865,12 @@ 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);