Commit 1bb4f2e8 authored Feb 24, 2018 by Jason Wang Committed by David S. Miller Feb 26, 2018

tuntap: correctly add the missing XDP flush



We don't flush batched XDP packets through xdp_do_flush_map(), this
will cause packets stall at TX queue. Consider we don't do XDP on NAPI
poll(), the only possible fix is to call xdp_do_flush_map()
immediately after xdp_do_redirect().

Note, this in fact won't try to batch packets through devmap, we could
address in the future.

Reported-by: Christoffer Dall <christoffer.dall@linaro.org>
Fixes: 761876c8 ("tap: XDP support")
Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 23e43f07

drivers/net/tun.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -1663,6 +1663,7 @@ static struct sk_buff tun_build_skb(struct tun_struct tun,
		get_page(alloc_frag->page);
		alloc_frag->offset += buflen;
		err = xdp_do_redirect(tun->dev, &xdp, xdp_prog);
		xdp_do_flush_map();
		if (err)
		goto err_redirect;
		rcu_read_unlock();

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