From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: Tue, 3 Mar 2020 15:54:48 +0000 (+0100)
Subject: add 4.9 tuntap patch
X-Git-Tag: v4.19.108~18
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=612a33f1564ec4b41d06bf09f087bfdfcc86cd5f;p=thirdparty%2Fkernel%2Fstable-queue.git

add 4.9 tuntap patch

script died previous attempt :(
---

diff --git a/queue-4.9/series b/queue-4.9/series
index d4d3d579130..6c7b664e8c7 100644
--- a/queue-4.9/series
+++ b/queue-4.9/series
@@ -43,3 +43,4 @@ net-ena-make-ena-rxfh-support-eth_rss_hash_no_change.patch
 namei-only-return-echild-from-follow_dotdot_rcu.patch
 kvm-check-for-a-bad-hva-before-dropping-into-the-ghc-slow-path.patch
 slip-stop-double-free-sl-dev-in-slip_open.patch
+tuntap-correctly-set-sockwq_async_nospace.patch
diff --git a/queue-4.9/tuntap-correctly-set-sockwq_async_nospace.patch b/queue-4.9/tuntap-correctly-set-sockwq_async_nospace.patch
new file mode 100644
index 00000000000..44b723119aa
--- /dev/null
+++ b/queue-4.9/tuntap-correctly-set-sockwq_async_nospace.patch
@@ -0,0 +1,68 @@
+From 2f3ab6221e4c87960347d65c7cab9bd917d1f637 Mon Sep 17 00:00:00 2001
+From: Jason Wang <jasowang@redhat.com>
+Date: Tue, 22 May 2018 14:21:04 +0800
+Subject: tuntap: correctly set SOCKWQ_ASYNC_NOSPACE
+
+From: Jason Wang <jasowang@redhat.com>
+
+commit 2f3ab6221e4c87960347d65c7cab9bd917d1f637 upstream.
+
+When link is down, writes to the device might fail with
+-EIO. Userspace needs an indication when the status is resolved.  As a
+fix, tun_net_open() attempts to wake up writers - but that is only
+effective if SOCKWQ_ASYNC_NOSPACE has been set in the past. This is
+not the case of vhost_net which only poll for EPOLLOUT after it meets
+errors during sendmsg().
+
+This patch fixes this by making sure SOCKWQ_ASYNC_NOSPACE is set when
+socket is not writable or device is down to guarantee EPOLLOUT will be
+raised in either tun_chr_poll() or tun_sock_write_space() after device
+is up.
+
+Cc: Hannes Frederic Sowa <hannes@stressinduktion.org>
+Cc: Eric Dumazet <edumazet@google.com>
+Fixes: 1bd4978a88ac2 ("tun: honor IFF_UP in tun_get_user()")
+Signed-off-by: Jason Wang <jasowang@redhat.com>
+Signed-off-by: David S. Miller <davem@davemloft.net>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+Signed-off-by: Tommi Rantala <tommi.t.rantala@nokia.com>
+
+---
+ drivers/net/tun.c |   19 +++++++++++++++----
+ 1 file changed, 15 insertions(+), 4 deletions(-)
+
+--- a/drivers/net/tun.c
++++ b/drivers/net/tun.c
+@@ -1106,6 +1106,13 @@ static void tun_net_init(struct net_devi
+ 	}
+ }
+ 
++static bool tun_sock_writeable(struct tun_struct *tun, struct tun_file *tfile)
++{
++	struct sock *sk = tfile->socket.sk;
++
++	return (tun->dev->flags & IFF_UP) && sock_writeable(sk);
++}
++
+ /* Character device part */
+ 
+ /* Poll */
+@@ -1128,10 +1135,14 @@ static unsigned int tun_chr_poll(struct
+ 	if (!skb_array_empty(&tfile->tx_array))
+ 		mask |= POLLIN | POLLRDNORM;
+ 
+-	if (tun->dev->flags & IFF_UP &&
+-	    (sock_writeable(sk) ||
+-	     (!test_and_set_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
+-	      sock_writeable(sk))))
++	/* Make sure SOCKWQ_ASYNC_NOSPACE is set if not writable to
++	 * guarantee EPOLLOUT to be raised by either here or
++	 * tun_sock_write_space(). Then process could get notification
++	 * after it writes to a down device and meets -EIO.
++	 */
++	if (tun_sock_writeable(tun, tfile) ||
++	    (!test_and_set_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
++	     tun_sock_writeable(tun, tfile)))
+ 		mask |= POLLOUT | POLLWRNORM;
+ 
+ 	if (tun->dev->reg_state != NETREG_REGISTERED)