[net PATCH] virtio_net: use dev_kfree_skb for small buffer XDP receive

[net PATCH] virtio_net: use dev_kfree_skb for small buffer XDP receive

[John Fastabend]

In the small buffer case during driver unload we currently use
put_page instead of dev_kfree_skb. Resolve this by adding a check
for virtnet mode when checking XDP queue type. Also name the
function so that the code reads correctly to match the additional
check.

Fixes: bb91accf2733 ("virtio-net: XDP support for small buffers")
Signed-off-by: John Fastabend <john.r.fastabend@intel.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
---
 drivers/net/virtio_net.c |    8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 3d1519e..4c6e9b4 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -1898,8 +1898,12 @@ static void free_receive_page_frags(struct virtnet_info *vi)
 			put_page(vi->rq[i].alloc_frag.page);
 }
 
-static bool is_xdp_queue(struct virtnet_info *vi, int q)
+static bool is_xdp_raw_buffer_queue(struct virtnet_info *vi, int q)
 {
+	/* For small receive mode always use kfree_skb variants */
+	if (!vi->mergeable_rx_bufs)
+		return false;
+
 	if (q < (vi->curr_queue_pairs - vi->xdp_queue_pairs))
 		return false;
 	else if (q < vi->curr_queue_pairs)
@@ -1916,7 +1920,7 @@ static void free_unused_bufs(struct virtnet_info *vi)
 	for (i = 0; i < vi->max_queue_pairs; i++) {
 		struct virtqueue *vq = vi->sq[i].vq;
 		while ((buf = virtqueue_detach_unused_buf(vq)) != NULL) {
-			if (!is_xdp_queue(vi, i))
+			if (!is_xdp_raw_buffer_queue(vi, i))
 				dev_kfree_skb(buf);
 			else
 				put_page(virt_to_head_page(buf));

Re: [net PATCH] virtio_net: use dev_kfree_skb for small buffer XDP receive

[David Miller]

From: John Fastabend <john.fastabend@gmail.com>
Date: Wed, 25 Jan 2017 18:22:48 -0800

> In the small buffer case during driver unload we currently use
> put_page instead of dev_kfree_skb. Resolve this by adding a check
> for virtnet mode when checking XDP queue type. Also name the
> function so that the code reads correctly to match the additional
> check.
> 
> Fixes: bb91accf2733 ("virtio-net: XDP support for small buffers")
> Signed-off-by: John Fastabend <john.r.fastabend@intel.com>
> Acked-by: Jason Wang <jasowang@redhat.com>
> Acked-by: Michael S. Tsirkin <mst@redhat.com>

Applied.