[V4,net,3/3] tuntap: correctly add the missing XDP flush
diff mbox series

Message ID 1519443146-9089-3-git-send-email-jasowang@redhat.com
State New, archived
Headers show
Series
  • [V4,net,1/3] Revert "tuntap: add missing xdp flush"
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Commit Message

Jason Wang Feb. 24, 2018, 3:32 a.m. UTC
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: 761876c857cb ("tap: XDP support")
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
 drivers/net/tun.c | 1 +
 1 file changed, 1 insertion(+)

Comments

David Miller Feb. 26, 2018, 6:50 p.m. UTC | #1
From: Jason Wang <jasowang@redhat.com>
Date: Sat, 24 Feb 2018 11:32:26 +0800

> 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: 761876c857cb ("tap: XDP support")
> Signed-off-by: Jason Wang <jasowang@redhat.com>

Applied, and all 3 patches queued up for -stable.

Thanks.

Patch
diff mbox series

diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 63d39fe6..7433bb2 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -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();