From: Gao Feng <f...@ikuai8.com> 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 <f...@ikuai8.com> --- drivers/net/tun.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/net/tun.c b/drivers/net/tun.c index 9328568..9142db8 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -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); -- 1.9.1