mac80211: refactor SKB queue processing a bit

This is a very long loop body, move it into its own function
instead, keeping only the kcov and free outside in the loop
body.

Link: https://lore.kernel.org/r/20210517230754.6bc6cdd68570.I28a86ebdb19601ca1965c4dc654cc49fc1064efa@changeidSigned-off-by: Johannes Berg <johannes.berg@intel.com>

net/mac80211/iface.c

@@ -1318,30 +1318,15 @@ static void ieee80211_if_setup_no_queue(struct net_device *dev)
 	dev->priv_flags |= IFF_NO_QUEUE;
 }
 
-static void ieee80211_iface_work(struct work_struct *work)
+static void ieee80211_iface_process_skb(struct ieee80211_local *local,
+					struct ieee80211_sub_if_data *sdata,
+					struct sk_buff *skb)
 {
-	struct ieee80211_sub_if_data *sdata =
-		container_of(work, struct ieee80211_sub_if_data, work);
-	struct ieee80211_local *local = sdata->local;
-	struct sk_buff *skb;
-	struct sta_info *sta;
-
-	if (!ieee80211_sdata_running(sdata))
-		return;
-
-	if (test_bit(SCAN_SW_SCANNING, &local->scanning))
-		return;
-
-	if (!ieee80211_can_run_worker(local))
-		return;
-
-	/* first process frames */
-	while ((skb = skb_dequeue(&sdata->skb_queue))) {
 	struct ieee80211_mgmt *mgmt = (void *)skb->data;
 
-		kcov_remote_start_common(skb_get_kcov_handle(skb));
 	if (ieee80211_is_action(mgmt->frame_control) &&
 	    mgmt->u.action.category == WLAN_CATEGORY_BACK) {
+		struct sta_info *sta;
 		int len = skb->len;
 
 		mutex_lock(&local->sta_mtx);
@@ -1349,8 +1334,8 @@ static void ieee80211_iface_work(struct work_struct *work)
 		if (sta) {
 			switch (mgmt->u.action.u.addba_req.action_code) {
 			case WLAN_ACTION_ADDBA_REQ:
-					ieee80211_process_addba_request(
-							local, sta, mgmt, len);
+				ieee80211_process_addba_request(local, sta,
+								mgmt, len);
 				break;
 			case WLAN_ACTION_ADDBA_RESP:
 				ieee80211_process_addba_resp(local, sta,
@@ -1372,6 +1357,7 @@ static void ieee80211_iface_work(struct work_struct *work)
 		case WLAN_VHT_ACTION_OPMODE_NOTIF: {
 			struct ieee80211_rx_status *status;
 			enum nl80211_band band;
+			struct sta_info *sta;
 			u8 opmode;
 
 			status = IEEE80211_SKB_RXCB(skb);
@@ -1382,8 +1368,7 @@ static void ieee80211_iface_work(struct work_struct *work)
 			sta = sta_info_get_bss(sdata, mgmt->sa);
 
 			if (sta)
-					ieee80211_vht_handle_opmode(sdata, sta,
-								    opmode,
+				ieee80211_vht_handle_opmode(sdata, sta, opmode,
 							    band);
 
 			mutex_unlock(&local->sta_mtx);
@@ -1403,6 +1388,8 @@ static void ieee80211_iface_work(struct work_struct *work)
 			WARN_ON(1);
 	} else if (ieee80211_is_data_qos(mgmt->frame_control)) {
 		struct ieee80211_hdr *hdr = (void *)mgmt;
+		struct sta_info *sta;
+
 		/*
 		 * So the frame isn't mgmt, but frame_control
 		 * is at the right place anyway, of course, so
@@ -1447,6 +1434,29 @@ static void ieee80211_iface_work(struct work_struct *work)
 		WARN(1, "frame for unexpected interface type");
 		break;
 	}
+}
+
+static void ieee80211_iface_work(struct work_struct *work)
+{
+	struct ieee80211_sub_if_data *sdata =
+		container_of(work, struct ieee80211_sub_if_data, work);
+	struct ieee80211_local *local = sdata->local;
+	struct sk_buff *skb;
+
+	if (!ieee80211_sdata_running(sdata))
+		return;
+
+	if (test_bit(SCAN_SW_SCANNING, &local->scanning))
+		return;
+
+	if (!ieee80211_can_run_worker(local))
+		return;
+
+	/* first process frames */
+	while ((skb = skb_dequeue(&sdata->skb_queue))) {
+		kcov_remote_start_common(skb_get_kcov_handle(skb));
+
+		ieee80211_iface_process_skb(local, sdata, skb);
 
 		kfree_skb(skb);
 		kcov_remote_stop();