3.12-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Zhi Yong Wu <redacted>

[ Upstream commit d0b7da8afa079ffe018ab3e92879b7138977fc8f ]

Signed-off-by: Zhi Yong Wu <redacted>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/net/tun.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c

@@ -1356,6 +1356,8 @@ static ssize_t tun_chr_aio_read(struct k
 	ret = tun_do_read(tun, tfile, iocb, iv, len,
 			  file->f_flags & O_NONBLOCK);
 	ret = min_t(ssize_t, ret, len);
+	if (ret > 0)
+		iocb->ki_pos = ret;
 out:
 	tun_put(tun);
 	return ret;