[PATCH net] netlink: mmap: fix tx type check

[Ken-ichirou MATSUZAWA <chamaken@gmail.com>]

I can't send netlink message via mmaped netlink socket since

    commit: a8866ff6a5bce7d0ec465a63bc482a85c09b0d39
    netlink: make the check for "send from tx_ring" deterministic

msg->msg_iter.type is set to WRITE (1) at

    SYSCALL_DEFINE6(sendto, ...
        import_single_range(WRITE, ...
            iov_iter_init(1, WRITE, ...

call path, so that we need to check the type by iter_is_iovec()
to accept the WRITE.

Signed-off-by: Ken-ichirou MATSUZAWA <chamas@h4.dion.ne.jp>
---
 net/netlink/af_netlink.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index 85ccd8b..4444687 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -2456,7 +2456,7 @@ static int netlink_sendmsg(struct socket *sock, struct msghdr *msg, size_t len)
 	 * sendmsg(), but that's what we've got...
 	 */
 	if (netlink_tx_is_mmaped(sk) &&
-	    msg->msg_iter.type == ITER_IOVEC &&
+	    iter_is_iovec(&msg->msg_iter) &&
 	    msg->msg_iter.nr_segs == 1 &&
 	    msg->msg_iter.iov->iov_base == NULL) {
 		err = netlink_mmap_sendmsg(sk, msg, dst_portid, dst_group,
-- 
1.7.10.4