On Mon, Sep 27, 2021 at 6:54 PM Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx> wrote:
>
> In the case of packed, use indirect desc, since desc is allocated by
> kmalloc_array(), we should check whether its return value is NULL.
>
> This patch alloc desc inside virtqueue_add_packe(), if desc == NULL,
> fall back to not using indirect.
>
> Fixes: 1ce9e6055fa ("virtio_ring: introduce packed ring support")
> Signed-off-by: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx>
Acked-by: Jason Wang <jasowang@xxxxxxxxxx>
> ---
> drivers/virtio/virtio_ring.c | 14 +++++++++-----
> 1 file changed, 9 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
> index 91a46c4da87d..62323c27bfe4 100644
> --- a/drivers/virtio/virtio_ring.c
> +++ b/drivers/virtio/virtio_ring.c
> @@ -1051,20 +1051,19 @@ static struct vring_packed_desc *alloc_indirect_packed(unsigned int total_sg,
>
> static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq,
> struct scatterlist *sgs[],
> + struct vring_packed_desc *desc,
> unsigned int total_sg,
> unsigned int out_sgs,
> unsigned int in_sgs,
> void *data,
> gfp_t gfp)
> {
> - struct vring_packed_desc *desc;
> struct scatterlist *sg;
> unsigned int i, n, err_idx;
> u16 head, id;
> dma_addr_t addr;
>
> head = vq->packed.next_avail_idx;
> - desc = alloc_indirect_packed(total_sg, gfp);
>
> if (unlikely(vq->vq.num_free < 1)) {
> pr_debug("Can't add buf len 1 - avail = 0\n");
> @@ -1191,9 +1190,14 @@ static inline int virtqueue_add_packed(struct virtqueue *_vq,
>
> BUG_ON(total_sg == 0);
>
> - if (virtqueue_use_indirect(_vq, total_sg))
> - return virtqueue_add_indirect_packed(vq, sgs, total_sg,
> - out_sgs, in_sgs, data, gfp);
> + if (virtqueue_use_indirect(_vq, total_sg)) {
> + desc = alloc_indirect_packed(total_sg, gfp);
> + if (desc)
> + return virtqueue_add_indirect_packed(vq, sgs, desc,
> + total_sg,
> + out_sgs, in_sgs,
> + data, gfp);
> + }
>
> head = vq->packed.next_avail_idx;
> avail_used_flags = vq->packed.avail_used_flags;
> --
> 2.31.0
>
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