tun: fix tun_chr_aio_write so that aio works

aio_write gets const struct iovec * but tun_chr_aio_write casts this to struct
iovec * and modifies the iovec. As a result, attempts to use io_submit
to send packets to a tun device fail with weird errors such as EINVAL.

Since tun is the only user of skb_copy_datagram_from_iovec, we can
fix this simply by changing the later so that it does not
touch the iovec passed to it.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 2 deletions

diff --git a/include/linux/socket.h b/include/linux/socket.h
index 171b08db9c4f..42a0396f2c59 100644
--- a/include/linux/socket.h
+++ b/include/linux/socket.h
@@ -309,8 +309,8 @@ struct ucred {
 
 #ifdef __KERNEL__
 extern int memcpy_fromiovec(unsigned char *kdata, struct iovec *iov, int len);
-extern int memcpy_fromiovecend(unsigned char *kdata, struct iovec *iov, 
-                                int offset, int len);
+extern int memcpy_fromiovecend(unsigned char *kdata, const struct iovec *iov,
+                               int offset, int len);
 extern int csum_partial_copy_fromiovecend(unsigned char *kdata, 
                                           struct iovec *iov, 
                                           int offset,