mac80211: mesh: move path tables into if_mesh

The mesh path and mesh gate hashtables are global, containing
all of the mpaths for every mesh interface, but the paths are
all tied logically to a single interface.  The common case is
just a single mesh interface, so optimize for that by moving
the global hashtable into the per-interface struct.

Doing so allows us to drop sdata pointer comparisons inside
the lookups and also saves a few bytes of BSS and data.

Signed-off-by: Bob Copeland <me@bobcopeland.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/mac80211/cfg.c

@@ -1499,7 +1499,7 @@ static void mpath_set_pinfo(struct mesh_path *mpath, u8 *next_hop,
 
 	memset(pinfo, 0, sizeof(*pinfo));
 
-	pinfo->generation = mesh_paths_generation;
+	pinfo->generation = mpath->sdata->u.mesh.mesh_paths_generation;
 
 	pinfo->filled = MPATH_INFO_FRAME_QLEN |
 			MPATH_INFO_SN |
@@ -1577,7 +1577,7 @@ static void mpp_set_pinfo(struct mesh_path *mpath, u8 *mpp,
 	memset(pinfo, 0, sizeof(*pinfo));
 	memcpy(mpp, mpath->mpp, ETH_ALEN);
 
-	pinfo->generation = mpp_paths_generation;
+	pinfo->generation = mpath->sdata->u.mesh.mpp_paths_generation;
 }
 
 static int ieee80211_get_mpp(struct wiphy *wiphy, struct net_device *dev,

net/mac80211/ieee80211_i.h

@@ -696,6 +696,18 @@ struct ieee80211_if_mesh {
 
 	/* offset from skb->data while building IE */
 	int meshconf_offset;
+
+	struct mesh_table __rcu *mesh_paths;
+	struct mesh_table __rcu *mpp_paths; /* Store paths for MPP&MAP */
+	int mesh_paths_generation;
+	int mpp_paths_generation;
+
+	/* Protects assignment of the mesh_paths/mpp_paths table
+	 * pointer for resize against reading it for add/delete
+	 * of individual paths.  Pure readers (lookups) just use
+	 * RCU.
+	 */
+	rwlock_t pathtbl_resize_lock;
 };
 
 #ifdef CONFIG_MAC80211_MESH

net/mac80211/mesh.c

@@ -25,7 +25,6 @@ bool mesh_action_is_path_sel(struct ieee80211_mgmt *mgmt)
 
 void ieee80211s_init(void)
 {
-	mesh_pathtbl_init();
 	mesh_allocated = 1;
 	rm_cache = kmem_cache_create("mesh_rmc", sizeof(struct rmc_entry),
 				     0, 0, NULL);
@@ -35,7 +34,6 @@ void ieee80211s_stop(void)
 {
 	if (!mesh_allocated)
 		return;
-	mesh_pathtbl_unregister();
 	kmem_cache_destroy(rm_cache);
 }
 
@@ -902,6 +900,7 @@ void ieee80211_stop_mesh(struct ieee80211_sub_if_data *sdata)
 	/* flush STAs and mpaths on this iface */
 	sta_info_flush(sdata);
 	mesh_path_flush_by_iface(sdata);
+	mesh_pathtbl_unregister(sdata);
 
 	/* free all potentially still buffered group-addressed frames */
 	local->total_ps_buffered -= skb_queue_len(&ifmsh->ps.bc_buf);
@@ -1349,10 +1348,10 @@ void ieee80211_mesh_work(struct ieee80211_sub_if_data *sdata)
 		mesh_path_start_discovery(sdata);
 
 	if (test_and_clear_bit(MESH_WORK_GROW_MPATH_TABLE, &ifmsh->wrkq_flags))
-		mesh_mpath_table_grow();
+		mesh_mpath_table_grow(sdata);
 
 	if (test_and_clear_bit(MESH_WORK_GROW_MPP_TABLE, &ifmsh->wrkq_flags))
-		mesh_mpp_table_grow();
+		mesh_mpp_table_grow(sdata);
 
 	if (test_and_clear_bit(MESH_WORK_HOUSEKEEPING, &ifmsh->wrkq_flags))
 		ieee80211_mesh_housekeeping(sdata);
@@ -1388,6 +1387,9 @@ void ieee80211_mesh_init_sdata(struct ieee80211_sub_if_data *sdata)
 	/* Allocate all mesh structures when creating the first mesh interface. */
 	if (!mesh_allocated)
 		ieee80211s_init();
+
+	mesh_pathtbl_init(sdata);
+
 	setup_timer(&ifmsh->mesh_path_timer,
 		    ieee80211_mesh_path_timer,
 		    (unsigned long) sdata);

net/mac80211/mesh.h

@@ -300,17 +300,17 @@ void mesh_sta_cleanup(struct sta_info *sta);
 
 /* Private interfaces */
 /* Mesh tables */
-void mesh_mpath_table_grow(void);
-void mesh_mpp_table_grow(void);
+void mesh_mpath_table_grow(struct ieee80211_sub_if_data *sdata);
+void mesh_mpp_table_grow(struct ieee80211_sub_if_data *sdata);
 /* Mesh paths */
 int mesh_path_error_tx(struct ieee80211_sub_if_data *sdata,
 		       u8 ttl, const u8 *target, u32 target_sn,
 		       u16 target_rcode, const u8 *ra);
 void mesh_path_assign_nexthop(struct mesh_path *mpath, struct sta_info *sta);
 void mesh_path_flush_pending(struct mesh_path *mpath);
 void mesh_path_tx_pending(struct mesh_path *mpath);
-int mesh_pathtbl_init(void);
-void mesh_pathtbl_unregister(void);
+int mesh_pathtbl_init(struct ieee80211_sub_if_data *sdata);
+void mesh_pathtbl_unregister(struct ieee80211_sub_if_data *sdata);
 int mesh_path_del(struct ieee80211_sub_if_data *sdata, const u8 *addr);
 void mesh_path_timer(unsigned long data);
 void mesh_path_flush_by_nexthop(struct sta_info *sta);
@@ -319,8 +319,6 @@ void mesh_path_discard_frame(struct ieee80211_sub_if_data *sdata,
 void mesh_path_tx_root_frame(struct ieee80211_sub_if_data *sdata);
 
 bool mesh_action_is_path_sel(struct ieee80211_mgmt *mgmt);
-extern int mesh_paths_generation;
-extern int mpp_paths_generation;
 
 #ifdef CONFIG_MAC80211_MESH
 static inline