cfg80211: simplify mesh BSS comparison

Instead of first checking if a BSS is an MBSS
and then doing the comparisons, inline it all
into the BSS comparison function. This avoids
doing the IE searches twice and is also a lot
less code.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/wireless/scan.c

@@ -288,26 +288,6 @@ const u8 *cfg80211_find_vendor_ie(unsigned int oui, u8 oui_type,
 }
 EXPORT_SYMBOL(cfg80211_find_vendor_ie);
 
-static int cmp_ies(u8 num, const u8 *ies1, int len1, const u8 *ies2, int len2)
-{
-	const u8 *ie1 = cfg80211_find_ie(num, ies1, len1);
-	const u8 *ie2 = cfg80211_find_ie(num, ies2, len2);
-
-	/* equal if both missing */
-	if (!ie1 && !ie2)
-		return 0;
-	/* sort missing IE before (left of) present IE */
-	if (!ie1)
-		return -1;
-	if (!ie2)
-		return 1;
-
-	/* sort by length first, then by contents */
-	if (ie1[1] != ie2[1])
-		return ie2[1] - ie1[1];
-	return memcmp(ie1 + 2, ie2 + 2, ie1[1]);
-}
-
 static bool is_bss(struct cfg80211_bss *a, const u8 *bssid,
 		   const u8 *ssid, size_t ssid_len)
 {
@@ -331,29 +311,6 @@ static bool is_bss(struct cfg80211_bss *a, const u8 *bssid,
 	return memcmp(ssidie + 2, ssid, ssid_len) == 0;
 }
 
-static bool is_mesh_bss(struct cfg80211_bss *a)
-{
-	const struct cfg80211_bss_ies *ies;
-	const u8 *ie;
-
-	if (!WLAN_CAPABILITY_IS_STA_BSS(a->capability))
-		return false;
-
-	ies = rcu_access_pointer(a->ies);
-	if (!ies)
-		return false;
-
-	ie = cfg80211_find_ie(WLAN_EID_MESH_ID, ies->data, ies->len);
-	if (!ie)
-		return false;
-
-	ie = cfg80211_find_ie(WLAN_EID_MESH_CONFIG, ies->data, ies->len);
-	if (!ie)
-		return false;
-
-	return true;
-}
-
 static bool is_mesh(struct cfg80211_bss *a,
 		    const u8 *meshid, size_t meshidlen,
 		    const u8 *meshcfg)
@@ -391,39 +348,6 @@ static bool is_mesh(struct cfg80211_bss *a,
 		      sizeof(struct ieee80211_meshconf_ie) - 2) == 0;
 }
 
-static int cmp_bss_core(struct cfg80211_bss *a, struct cfg80211_bss *b)
-{
-	const struct cfg80211_bss_ies *a_ies, *b_ies;
-	int r;
-
-	if (a->channel != b->channel)
-		return b->channel->center_freq - a->channel->center_freq;
-
-	if (is_mesh_bss(a) && is_mesh_bss(b)) {
-		a_ies = rcu_access_pointer(a->ies);
-		if (!a_ies)
-			return -1;
-		b_ies = rcu_access_pointer(b->ies);
-		if (!b_ies)
-			return 1;
-
-		r = cmp_ies(WLAN_EID_MESH_ID,
-			    a_ies->data, a_ies->len,
-			    b_ies->data, b_ies->len);
-		if (r)
-			return r;
-		return cmp_ies(WLAN_EID_MESH_CONFIG,
-			       a_ies->data, a_ies->len,
-			       b_ies->data, b_ies->len);
-	}
-
-	/*
-	 * we can't use compare_ether_addr here since we need a < > operator.
-	 * The binary return value of compare_ether_addr isn't enough
-	 */
-	return memcmp(a->bssid, b->bssid, sizeof(a->bssid));
-}
-
 /**
  * enum bss_compare_mode - BSS compare mode
  * @BSS_CMP_REGULAR: regular compare mode (for insertion and normal find)
@@ -441,13 +365,12 @@ static int cmp_bss(struct cfg80211_bss *a,
 		   enum bss_compare_mode mode)
 {
 	const struct cfg80211_bss_ies *a_ies, *b_ies;
-	const u8 *ie1;
-	const u8 *ie2;
+	const u8 *ie1 = NULL;
+	const u8 *ie2 = NULL;
 	int i, r;
 
-	r = cmp_bss_core(a, b);
-	if (r)
-		return r;
+	if (a->channel != b->channel)
+		return b->channel->center_freq - a->channel->center_freq;
 
 	a_ies = rcu_access_pointer(a->ies);
 	if (!a_ies)
@@ -456,6 +379,41 @@ static int cmp_bss(struct cfg80211_bss *a,
 	if (!b_ies)
 		return 1;
 
+	if (WLAN_CAPABILITY_IS_STA_BSS(a->capability))
+		ie1 = cfg80211_find_ie(WLAN_EID_MESH_ID,
+				       a_ies->data, a_ies->len);
+	if (WLAN_CAPABILITY_IS_STA_BSS(b->capability))
+		ie2 = cfg80211_find_ie(WLAN_EID_MESH_ID,
+				       b_ies->data, b_ies->len);
+	if (ie1 && ie2) {
+		int mesh_id_cmp;
+
+		if (ie1[1] == ie2[1])
+			mesh_id_cmp = memcmp(ie1 + 2, ie2 + 2, ie1[1]);
+		else
+			mesh_id_cmp = ie2[1] - ie1[1];
+
+		ie1 = cfg80211_find_ie(WLAN_EID_MESH_CONFIG,
+				       a_ies->data, a_ies->len);
+		ie2 = cfg80211_find_ie(WLAN_EID_MESH_CONFIG,
+				       b_ies->data, b_ies->len);
+		if (ie1 && ie2) {
+			if (mesh_id_cmp)
+				return mesh_id_cmp;
+			if (ie1[1] != ie2[1])
+				return ie2[1] - ie1[1];
+			return memcmp(ie1 + 2, ie2 + 2, ie1[1]);
+		}
+	}
+
+	/*
+	 * we can't use compare_ether_addr here since we need a < > operator.
+	 * The binary return value of compare_ether_addr isn't enough
+	 */
+	r = memcmp(a->bssid, b->bssid, sizeof(a->bssid));
+	if (r)
+		return r;
+
 	ie1 = cfg80211_find_ie(WLAN_EID_SSID, a_ies->data, a_ies->len);
 	ie2 = cfg80211_find_ie(WLAN_EID_SSID, b_ies->data, b_ies->len);