On Thu, Jun 26, 2025 at 12:10 AM Bui Quang Minh
<minhquangbui99@gmail.com> wrote:
>
> The truesize is guaranteed not to exceed PAGE_SIZE in
> get_mergeable_buf_len(). It is saved in mergeable context, which is not
> changeable by the host side,
This really depends on the security model.
> so the check in receive path is quite
> redundant.
>
> Signed-off-by: Bui Quang Minh <minhquangbui99@gmail.com>
> ---
> drivers/net/virtio_net.c | 7 +++----
> 1 file changed, 3 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index 2a130a3e50ac..6f9fedad4a5e 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -2144,9 +2144,9 @@ static int virtnet_build_xdp_buff_mrg(struct net_device *dev,
> {
> struct virtio_net_hdr_mrg_rxbuf *hdr = buf;
> unsigned int headroom, tailroom, room;
> - unsigned int truesize, cur_frag_size;
> struct skb_shared_info *shinfo;
> unsigned int xdp_frags_truesz = 0;
> + unsigned int truesize;
> struct page *page;
> skb_frag_t *frag;
> int offset;
> @@ -2194,9 +2194,8 @@ static int virtnet_build_xdp_buff_mrg(struct net_device *dev,
> tailroom = headroom ? sizeof(struct skb_shared_info) : 0;
> room = SKB_DATA_ALIGN(headroom + tailroom);
>
> - cur_frag_size = truesize;
> - xdp_frags_truesz += cur_frag_size;
> - if (unlikely(len > truesize - room || cur_frag_size > PAGE_SIZE)) {
> + xdp_frags_truesz += truesize;
> + if (unlikely(len > truesize - room)) {
> put_page(page);
> pr_debug("%s: rx error: len %u exceeds truesize %lu\n",
> dev->name, len, (unsigned long)(truesize - room));
> --
> 2.43.0
>
Acked-by: Jason Wang <jasowang@redhat.com>
Thanks