On Wed, May 06, 2020 at 02:16:33PM +0800, Jason Wang wrote: > We should not exclude headroom and tailroom when XDP is set. So this > patch fixes this by initializing the truesize from PAGE_SIZE when XDP > is set. > > Cc: Jesper Dangaard Brouer <bro...@redhat.com> > Signed-off-by: Jason Wang <jasow...@redhat.com>
Seems too aggressive, we do not use up the whole page for the size. > --- > drivers/net/virtio_net.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c > index 98dd75b665a5..3f3aa8308918 100644 > --- a/drivers/net/virtio_net.c > +++ b/drivers/net/virtio_net.c > @@ -1184,7 +1184,7 @@ static int add_recvbuf_mergeable(struct virtnet_info > *vi, > char *buf; > void *ctx; > int err; > - unsigned int len, hole; > + unsigned int len, hole, truesize; > > /* Extra tailroom is needed to satisfy XDP's assumption. This > * means rx frags coalescing won't work, but consider we've > @@ -1194,6 +1194,7 @@ static int add_recvbuf_mergeable(struct virtnet_info > *vi, > if (unlikely(!skb_page_frag_refill(len + room, alloc_frag, gfp))) > return -ENOMEM; > > + truesize = headroom ? PAGE_SIZE : len; > buf = (char *)page_address(alloc_frag->page) + alloc_frag->offset; > buf += headroom; /* advance address leaving hole at front of pkt */ > get_page(alloc_frag->page); Is this really just on the XDP path? Looks like a confusing way to detect that. > @@ -1205,11 +1206,12 @@ static int add_recvbuf_mergeable(struct virtnet_info > *vi, > * the current buffer. > */ > len += hole; > + truesize += hole; > alloc_frag->offset += hole; > } > > sg_init_one(rq->sg, buf, len); > - ctx = mergeable_len_to_ctx(len, headroom); > + ctx = mergeable_len_to_ctx(truesize, headroom); > err = virtqueue_add_inbuf_ctx(rq->vq, rq->sg, 1, buf, ctx, gfp); > if (err < 0) > put_page(virt_to_head_page(buf)); > -- > 2.20.1
