[PATCH bpf-next v3 2/3] bpf: xdp, virtio_net use access ptr macro for xdp enable check
From: John Fastabend <john.fastabend@gmail.com>
Date: 2020-01-27 00:14:42
Also in:
bpf
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, Eugenio Pérez
virtio_net currently relies on rcu critical section to access the xdp program in its xdp_xmit handler. However, the pointer to the xdp program is only used to do a NULL pointer comparison to determine if xdp is enabled or not. Use rcu_access_pointer() instead of rcu_dereference() to reflect this. Then later when we drop rcu_read critical section virtio_net will not need in special handling. Acked-by: Jesper Dangaard Brouer <redacted> Signed-off-by: John Fastabend <john.fastabend@gmail.com> --- drivers/net/virtio_net.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 4d7d5434..945eabc 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c@@ -501,7 +501,7 @@ static int virtnet_xdp_xmit(struct net_device *dev, /* Only allow ndo_xdp_xmit if XDP is loaded on dev, as this * indicate XDP resources have been successfully allocated. */ - xdp_prog = rcu_dereference(rq->xdp_prog); + xdp_prog = rcu_access_pointer(rq->xdp_prog); if (!xdp_prog) return -ENXIO;
--
2.7.4