lkml.org 
[lkml]   [2022]   [Mar]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 5.16 019/121] virtio-blk: Remove BUG_ON() in virtio_queue_rq()
    Date
    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));

    --
    2.34.1


    \
     
     \ /
      Last update: 2022-03-14 13:33    [W:3.026 / U:0.048 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site