driver: tun: Move tun check into the block of TUNSETIFF condition check
authorGao Feng <fgao@ikuai8.com>
Tue, 25 Oct 2016 14:26:09 +0000 (22:26 +0800)
committerDavid S. Miller <davem@davemloft.net>
Sat, 29 Oct 2016 18:51:42 +0000 (14:51 -0400)
When cmd is TUNSETIFF and tun is not null, the original codes go ahead,
then reach the default case of switch(cmd) and set the ret is -EINVAL.
It is not clear for readers.

Now move the tun check into the block of TUNSETIFF condition check, and
return -EEXIST instead of -EINVAL when the tfile already owns one tun.

Signed-off-by: Gao Feng <fgao@ikuai8.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
drivers/net/tun.c

index 93285687cf13ea28ad5627953d91b6d164eab100..9142db847ee156f8e29dab9856cbcc90021ac541 100644 (file)
@@ -2005,7 +2005,11 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
        rtnl_lock();
 
        tun = __tun_get(tfile);
-       if (cmd == TUNSETIFF && !tun) {
+       if (cmd == TUNSETIFF) {
+               ret = -EEXIST;
+               if (tun)
+                       goto unlock;
+
                ifr.ifr_name[IFNAMSIZ-1] = '\0';
 
                ret = tun_set_iff(sock_net(&tfile->sk), file, &ifr);