From: Xie Yongji xieyongji@bytedance.com
[ Upstream commit e030759a1ddcbf61d42b6e996bfeb675e0032d8b ]
Currently we have a BUG_ON() to make sure the number of sg list does not exceed queue_max_segments() in virtio_queue_rq(). However, the block layer uses queue_max_discard_segments() instead of queue_max_segments() to limit the sg list for discard requests. So the BUG_ON() might be triggered if virtio-blk device reports a larger value for max discard segment than queue_max_segments(). To fix it, let's simply remove the BUG_ON() which has become unnecessary after commit 02746e26c39e("virtio-blk: avoid preallocating big SGL for data"). And the unused vblk->sg_elems can also be removed together.
Fixes: 1f23816b8eb8 ("virtio_blk: add discard and write zeroes support") Suggested-by: Christoph Hellwig hch@infradead.org Signed-off-by: Xie Yongji xieyongji@bytedance.com Reviewed-by: Max Gurtovoy mgurtovoy@nvidia.com Link: https://lore.kernel.org/r/20220304100058.116-2-xieyongji@bytedance.com Signed-off-by: Michael S. Tsirkin mst@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/block/virtio_blk.c | 12 ++---------- 1 file changed, 2 insertions(+), 10 deletions(-)
diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c index 87f239eb0a99..b3df5e5452a7 100644 --- a/drivers/block/virtio_blk.c +++ b/drivers/block/virtio_blk.c @@ -76,9 +76,6 @@ struct virtio_blk { */ refcount_t refs;
- /* What host tells us, plus 2 for header & tailer. */ - unsigned int sg_elems; - /* Ida index - used to track minor number allocations. */ int index;
@@ -322,8 +319,6 @@ static blk_status_t virtio_queue_rq(struct blk_mq_hw_ctx *hctx, blk_status_t status; int err;
- BUG_ON(req->nr_phys_segments + 2 > vblk->sg_elems); - status = virtblk_setup_cmd(vblk->vdev, req, vbr); if (unlikely(status)) return status; @@ -783,8 +778,6 @@ static int virtblk_probe(struct virtio_device *vdev) /* Prevent integer overflows and honor max vq size */ sg_elems = min_t(u32, sg_elems, VIRTIO_BLK_MAX_SG_ELEMS - 2);
- /* We need extra sg elements at head and tail. */ - sg_elems += 2; vdev->priv = vblk = kmalloc(sizeof(*vblk), GFP_KERNEL); if (!vblk) { err = -ENOMEM; @@ -796,7 +789,6 @@ static int virtblk_probe(struct virtio_device *vdev) mutex_init(&vblk->vdev_mutex);
vblk->vdev = vdev; - vblk->sg_elems = sg_elems;
INIT_WORK(&vblk->config_work, virtblk_config_changed_work);
@@ -854,7 +846,7 @@ static int virtblk_probe(struct virtio_device *vdev) set_disk_ro(vblk->disk, 1);
/* We can handle whatever the host told us to handle. */ - blk_queue_max_segments(q, vblk->sg_elems-2); + blk_queue_max_segments(q, sg_elems);
/* No real sector limit. */ blk_queue_max_hw_sectors(q, -1U); @@ -932,7 +924,7 @@ static int virtblk_probe(struct virtio_device *vdev) * handled it. */ if (!v) - v = sg_elems - 2; + v = sg_elems; blk_queue_max_discard_segments(q, min(v, MAX_DISCARD_SEGMENTS));