diff mbox series

[net-next,v4,07/10] virtio-net: transmit the multi-buffer xdp

Message ID 20230113080016.45505-8-hengqi@linux.alibaba.com (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series virtio-net: support multi buffer xdp | expand

Checks

Context Check Description
netdev/tree_selection success Clearly marked for net-next
netdev/fixes_present success Fixes tag not required for -next series
netdev/subject_prefix success Link
netdev/cover_letter success Series has a cover letter
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 0 this patch: 0
netdev/cc_maintainers warning 2 maintainers not CCed: virtualization@lists.linux-foundation.org hawk@kernel.org
netdev/build_clang success Errors and warnings before: 0 this patch: 0
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 0 this patch: 0
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 48 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Heng Qi Jan. 13, 2023, 8 a.m. UTC
This serves as the basis for XDP_TX and XDP_REDIRECT
to send a multi-buffer xdp_frame.

Signed-off-by: Heng Qi <hengqi@linux.alibaba.com>
Reviewed-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Acked-by: Jason Wang <jasowang@redhat.com>
---
 drivers/net/virtio_net.c | 31 ++++++++++++++++++++++++++-----
 1 file changed, 26 insertions(+), 5 deletions(-)
diff mbox series

Patch

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index ab01cf3855bc..fee9ce31f6c7 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -563,22 +563,43 @@  static int __virtnet_xdp_xmit_one(struct virtnet_info *vi,
 				   struct xdp_frame *xdpf)
 {
 	struct virtio_net_hdr_mrg_rxbuf *hdr;
-	int err;
+	struct skb_shared_info *shinfo;
+	u8 nr_frags = 0;
+	int err, i;
 
 	if (unlikely(xdpf->headroom < vi->hdr_len))
 		return -EOVERFLOW;
 
-	/* Make room for virtqueue hdr (also change xdpf->headroom?) */
+	if (unlikely(xdp_frame_has_frags(xdpf))) {
+		shinfo = xdp_get_shared_info_from_frame(xdpf);
+		nr_frags = shinfo->nr_frags;
+	}
+
+	/* In wrapping function virtnet_xdp_xmit(), we need to free
+	 * up the pending old buffers, where we need to calculate the
+	 * position of skb_shared_info in xdp_get_frame_len() and
+	 * xdp_return_frame(), which will involve to xdpf->data and
+	 * xdpf->headroom. Therefore, we need to update the value of
+	 * headroom synchronously here.
+	 */
+	xdpf->headroom -= vi->hdr_len;
 	xdpf->data -= vi->hdr_len;
 	/* Zero header and leave csum up to XDP layers */
 	hdr = xdpf->data;
 	memset(hdr, 0, vi->hdr_len);
 	xdpf->len   += vi->hdr_len;
 
-	sg_init_one(sq->sg, xdpf->data, xdpf->len);
+	sg_init_table(sq->sg, nr_frags + 1);
+	sg_set_buf(sq->sg, xdpf->data, xdpf->len);
+	for (i = 0; i < nr_frags; i++) {
+		skb_frag_t *frag = &shinfo->frags[i];
+
+		sg_set_page(&sq->sg[i + 1], skb_frag_page(frag),
+			    skb_frag_size(frag), skb_frag_off(frag));
+	}
 
-	err = virtqueue_add_outbuf(sq->vq, sq->sg, 1, xdp_to_ptr(xdpf),
-				   GFP_ATOMIC);
+	err = virtqueue_add_outbuf(sq->vq, sq->sg, nr_frags + 1,
+				   xdp_to_ptr(xdpf), GFP_ATOMIC);
 	if (unlikely(err))
 		return -ENOSPC; /* Caller handle free/refcnt */