[bpf-next V3 PATCH 07/15] virtio_net: convert to use generic xdp_frame and xdp_return_frame API
From: Jesper Dangaard Brouer <hidden>
Date: 2018-03-09 20:55:42
Subsystem:
networking drivers, the rest, virtio net driver · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds, "Michael S. Tsirkin", Jason Wang
The virtio_net driver assumes XDP frames are always released based on page refcnt (via put_page). Thus, is only queues the XDP data pointer address and uses virt_to_head_page() to retrieve struct page. Use the XDP return API to get away from such assumptions. Instead queue an xdp_frame, which allow us to use the xdp_return_frame API, when releasing the frame. Signed-off-by: Jesper Dangaard Brouer <redacted> --- drivers/net/virtio_net.c | 31 +++++++++++++++++++++---------- 1 file changed, 21 insertions(+), 10 deletions(-)
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 23374603e4d9..6c4220450506 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c@@ -419,30 +419,41 @@ static bool __virtnet_xdp_xmit(struct virtnet_info *vi, struct xdp_buff *xdp) { struct virtio_net_hdr_mrg_rxbuf *hdr; - unsigned int len; + struct xdp_frame *xdpf, *xdpf_sent; struct send_queue *sq; + unsigned int len; unsigned int qp; - void *xdp_sent; int err; qp = vi->curr_queue_pairs - vi->xdp_queue_pairs + smp_processor_id(); sq = &vi->sq[qp]; /* Free up any pending old buffers before queueing new ones. */ - while ((xdp_sent = virtqueue_get_buf(sq->vq, &len)) != NULL) { - struct page *sent_page = virt_to_head_page(xdp_sent); + while ((xdpf_sent = virtqueue_get_buf(sq->vq, &len)) != NULL) + xdp_return_frame(xdpf_sent->data, &xdpf_sent->mem); - put_page(sent_page); - } + xdpf = convert_to_xdp_frame(xdp); + if (unlikely(!xdpf)) + return -EOVERFLOW; + + /* virtqueue want to use data area in-front of packet */ + if (unlikely(xdpf->metasize > 0)) + return -EOPNOTSUPP; + + if (unlikely(xdpf->headroom < vi->hdr_len)) + return -EOVERFLOW; - xdp->data -= vi->hdr_len; + /* Make room for virtqueue hdr (also change xdpf->headroom?) */ + xdpf->data -= vi->hdr_len; /* Zero header and leave csum up to XDP layers */ - hdr = xdp->data; + hdr = xdpf->data; memset(hdr, 0, vi->hdr_len); + hdr->hdr.hdr_len = xdpf->len; /* Q: is this needed? */ + xdpf->len += vi->hdr_len; - sg_init_one(sq->sg, xdp->data, xdp->data_end - xdp->data); + sg_init_one(sq->sg, xdpf->data, xdpf->len); - err = virtqueue_add_outbuf(sq->vq, sq->sg, 1, xdp->data, GFP_ATOMIC); + err = virtqueue_add_outbuf(sq->vq, sq->sg, 1, xdpf, GFP_ATOMIC); if (unlikely(err)) return false; /* Caller handle free/refcnt */