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virtio-blk: Remove BUG_ON() in virtio_queue_rq()

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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: 1f23816b8e ("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>
This commit is contained in:
Xie Yongji 2022-03-04 18:00:58 +08:00 committed by Michael S. Tsirkin
parent dacc73ed0b
commit e030759a1d
1 changed files with 2 additions and 10 deletions
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12
drivers/block/virtio_blk.c
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@ -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);
@ -853,7 +845,7 @@ 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);
@ -931,7 +923,7 @@ 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));