cfg80211: correct bridge/4addr mode check

stable inclusion
from stable-5.10.77
commit 04121b10cdf0361c0fac761a9264659935878693
bugzilla: 185677 https://gitee.com/openeuler/kernel/issues/I4IAP7

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=04121b10cdf0361c0fac761a9264659935878693

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

commit 689a0a9f upstream.

Without the patch we fail:

$ sudo brctl addbr br0
$ sudo brctl addif br0 wlp1s0
$ sudo iw wlp1s0 set 4addr on
command failed: Device or resource busy (-16)

Last command failed but iface was already in 4addr mode.

Fixes: ad4bb6f8 ("cfg80211: disallow bridging managed/adhoc interfaces")
Signed-off-by: NJanusz Dziedzic <janusz.dziedzic@gmail.com>
Link: https://lore.kernel.org/r/20211024201546.614379-1-janusz.dziedzic@gmail.com
[add fixes tag, fix indentation, edit commit log]
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Acked-by: NWeilong Chen <chenweilong@huawei.com>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

net/wireless/util.c

@@ -1028,6 +1028,7 @@ int cfg80211_change_iface(struct cfg80211_registered_device *rdev,
 	    !(rdev->wiphy.interface_modes & (1 << ntype)))
 		return -EOPNOTSUPP;
 
+	if (ntype != otype) {
 		/* if it's part of a bridge, reject changing type to station/ibss */
 		if (netif_is_bridge_port(dev) &&
 		    (ntype == NL80211_IFTYPE_ADHOC ||
@@ -1035,7 +1036,6 @@ int cfg80211_change_iface(struct cfg80211_registered_device *rdev,
 		     ntype == NL80211_IFTYPE_P2P_CLIENT))
 			return -EBUSY;
 
-	if (ntype != otype) {
 		dev->ieee80211_ptr->use_4addr = false;
 		dev->ieee80211_ptr->mesh_id_up_len = 0;
 		wdev_lock(dev->ieee80211_ptr);