Patch "tuntap: correctly add the missing XDP flush" has been added to the 4.14-stable tree

This is a note to let you know that I've just added the patch titled

tuntap: correctly add the missing XDP flush

to the 4.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
tuntap-correctly-add-the-missing-xdp-flush.patch
and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Jason Wang <[email protected]>
Date: Sat, 24 Feb 2018 11:32:26 +0800
Subject: tuntap: correctly add the missing XDP flush

From: Jason Wang <[email protected]>

[ Upstream commit 1bb4f2e868a2891ab8bc668b8173d6ccb8c4ce6f ]

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.

---
 drivers/net/tun.c |    1 +
 1 file changed, 1 insertion(+)

@@ -1333,6 +1333,7 @@ static struct sk_buff *tun_build_skb(str
 			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();

Patches currently in stable-queue which might be from [email protected] are

queue-4.14/tuntap-correctly-add-the-missing-xdp-flush.patch queue-4.14/virtio-net-disable-napi-only-when-enabled-during-xdp-set.patch queue-4.14/tuntap-disable-preemption-during-xdp-processing.patch