cfg80211: regulatory: reset regdomain in case of error

Reset regdomain to world regdomain in case
of errors in set_regdom() function.

This will fix a problem with such scenario:
- iw reg set US
- iw reg set 00
- iw reg set US
The last step always fail and we get deadlock
in kernel regulatory code. Next setting new
regulatory wasn't possible due to:

Pending regulatory request, waiting for it to be processed...
Signed-off-by: NJanusz Dziedzic <janusz.dziedzic@tieto.com>
Acked-by: NLuis R. Rodriguez <mcgrof@do-not-panic.com>
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

net/wireless/reg.c

@@ -2373,6 +2373,7 @@ static int reg_set_rd_country_ie(const struct ieee80211_regdomain *rd,
 int set_regdom(const struct ieee80211_regdomain *rd)
 {
 	struct regulatory_request *lr;
+	bool user_reset = false;
 	int r;
 
 	if (!reg_is_valid_request(rd->alpha2)) {
@@ -2389,6 +2390,7 @@ int set_regdom(const struct ieee80211_regdomain *rd)
 		break;
 	case NL80211_REGDOM_SET_BY_USER:
 		r = reg_set_rd_user(rd, lr);
+		user_reset = true;
 		break;
 	case NL80211_REGDOM_SET_BY_DRIVER:
 		r = reg_set_rd_driver(rd, lr);
@@ -2402,8 +2404,14 @@ int set_regdom(const struct ieee80211_regdomain *rd)
 	}
 
 	if (r) {
-		if (r == -EALREADY)
+		switch (r) {
+		case -EALREADY:
 			reg_set_request_processed();
+			break;
+		default:
+			/* Back to world regulatory in case of errors */
+			restore_regulatory_settings(user_reset);
+		}
 
 		kfree(rd);
 		return r;