wifi: mac80211: simplify return value handling of cfg80211_get_radio_idx_by_chan()

JIRA: https://issues.redhat.com/browse/RHEL-114891

commit cfb58d5
Author: Aditya Kumar Singh <aditya.kumar.singh@oss.qualcomm.com>
Date:   Tue Aug 12 12:53:29 2025 +0530

    wifi: mac80211: simplify return value handling of cfg80211_get_radio_idx_by_chan()
    
    In several instances where cfg80211_get_radio_idx_by_chan() is called,
    redundant checks are performed across function — such as verifying if
    wiphy->n_radio < 2 or if the returned index is negative. These checks are
    unnecessary, as the return value can be directly compared. Moreover, the
    function can be safely called even when radio-level properties are not
    explicitly advertised since in such case in each call it is going to get
    same error value.
    
    Therefore, simplify the usage of this function across all such cases by
    removing redundant conditions and relying on the return value directly.
    
    Signed-off-by: Aditya Kumar Singh <aditya.kumar.singh@oss.qualcomm.com>
    Link: https://patch.msgid.link/20250812-fix_scan_ap_flag_requirement_during_mlo-v4-2-383ffb6da213@oss.qualcomm.com
    Signed-off-by: Johannes Berg <johannes.berg@intel.com>

Signed-off-by: Jose Ignacio Tornos Martinez <jtornosm@redhat.com>

Author: jtornosm

net/mac80211/cfg.c

@@ -3690,12 +3690,7 @@ static bool ieee80211_is_scan_ongoing(struct wiphy *wiphy,
 	if (list_empty(&local->roc_list) && !local->scanning)
 		return false;
 
-	if (wiphy->n_radio < 2)
-		return true;
-
 	req_radio_idx = cfg80211_get_radio_idx_by_chan(wiphy, chandef->chan);
-	if (req_radio_idx < 0)
-		return true;
 
 	if (local->scanning) {
 		scan_req = wiphy_dereference(wiphy, local->scan_req);
@@ -3714,14 +3709,6 @@ static bool ieee80211_is_scan_ongoing(struct wiphy *wiphy,
 	list_for_each_entry(roc, &local->roc_list, list) {
 		chan_radio_idx = cfg80211_get_radio_idx_by_chan(wiphy,
 								roc->chan);
-		/*
-		 * The roc work is added but chan_radio_idx is invalid.
-		 * Should not happen but if it does, let's not take
-		 * risk and return true.
-		 */
-		if (chan_radio_idx < 0)
-			return true;
-
 		if (chan_radio_idx == req_radio_idx)
 			return true;
 	}

net/mac80211/chan.c

@@ -659,19 +659,8 @@ bool ieee80211_is_radar_required(struct ieee80211_local *local,
 
 	for_each_sdata_link(local, link) {
 		if (link->radar_required) {
-			if (wiphy->n_radio < 2)
-				return true;
-
 			chan = link->conf->chanreq.oper.chan;
 			radio_idx = cfg80211_get_radio_idx_by_chan(wiphy, chan);
-			/*
-			 * The radio index (radio_idx) is expected to be valid,
-			 * as it's derived from a channel tied to a link. If
-			 * it's invalid (i.e., negative), return true to avoid
-			 * potential issues with radar-sensitive operations.
-			 */
-			if (radio_idx < 0)
-				return true;
 
 			if (ieee80211_is_radio_idx_in_scan_req(wiphy, req,
 							       radio_idx))

net/mac80211/util.c

@@ -4022,16 +4022,13 @@ bool ieee80211_is_radio_idx_in_scan_req(struct wiphy *wiphy,
 	for (i = 0; i < scan_req->n_channels; i++) {
 		chan = scan_req->channels[i];
 		chan_radio_idx = cfg80211_get_radio_idx_by_chan(wiphy, chan);
-		/*
-		 * The chan_radio_idx should be valid since it's taken from a
-		 * valid scan request.
-		 * However, if chan_radio_idx is unexpectedly invalid (negative),
-		 * we take a conservative approach and assume the scan request
-		 * might use the specified radio_idx. Hence, return true.
-		 */
-		if (WARN_ON(chan_radio_idx < 0))
-			return true;
 
+		/* The radio index either matched successfully, or an error
+		 * occurred. For example, if radio-level information is
+		 * missing, the same error value is returned. This
+		 * typically implies a single-radio setup, in which case
+		 * the operation should not be allowed.
+		 */
 		if (chan_radio_idx == radio_idx)
 			return true;
 	}