mac80211: Consolidate mesh path duplicated functions

Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 28 insertions, 42 deletions

diff --git a/net/mac80211/mesh_pathtbl.c b/net/mac80211/mesh_pathtbl.c
index 7797f55eec46..a66a2cab8d34 100644
--- a/net/mac80211/mesh_pathtbl.c
+++ b/net/mac80211/mesh_pathtbl.c
@@ -48,10 +48,10 @@ static struct mesh_table __rcu *mpp_paths; /* Store paths for MPP&MAP */
 int mesh_paths_generation;
 
 /* This lock will have the grow table function as writer and add / delete nodes
- * as readers. When reading the table (i.e. doing lookups) we are well protected
- * by RCU.  We need to take this lock when modying the number of buckets
- * on one of the path tables but we don't need to if adding or removing mpaths
- * from hash buckets.
+ * as readers. RCU provides sufficient protection only when reading the table
+ * (i.e. doing lookups).  Adding or adding or removing nodes requires we take
+ * the read lock or we risk operating on an old table.  The write lock is only
+ * needed when modifying the number of buckets a table.
  */
 static DEFINE_RWLOCK(pathtbl_resize_lock);
 
@@ -335,25 +335,14 @@ static void mesh_path_move_to_queue(struct mesh_path *gate_mpath,
 }
 
 
-/**
- * mesh_path_lookup - look up a path in the mesh path table
- * @dst: hardware address (ETH_ALEN length) of destination
- * @sdata: local subif
- *
- * Returns: pointer to the mesh path structure, or NULL if not found
- *
- * Locking: must be called within a read rcu section.
- */
-struct mesh_path *mesh_path_lookup(u8 *dst, struct ieee80211_sub_if_data *sdata)
+static struct mesh_path *path_lookup(struct mesh_table *tbl, u8 *dst,
+                                          struct ieee80211_sub_if_data *sdata)
 {
         struct mesh_path *mpath;
         struct hlist_node *n;
         struct hlist_head *bucket;
-        struct mesh_table *tbl;
         struct mpath_node *node;
 
-        tbl = rcu_dereference(mesh_paths);
-
         bucket = &tbl->hash_buckets[mesh_table_hash(dst, sdata, tbl)];
         hlist_for_each_entry_rcu(node, n, bucket, list) {
                 mpath = node->mpath;
@@ -370,30 +359,23 @@ struct mesh_path *mesh_path_lookup(u8 *dst, struct ieee80211_sub_if_data *sdata)
         return NULL;
 }
 
-struct mesh_path *mpp_path_lookup(u8 *dst, struct ieee80211_sub_if_data *sdata)
+/**
+ * mesh_path_lookup - look up a path in the mesh path table
+ * @dst: hardware address (ETH_ALEN length) of destination
+ * @sdata: local subif
+ *
+ * Returns: pointer to the mesh path structure, or NULL if not found
+ *
+ * Locking: must be called within a read rcu section.
+ */
+struct mesh_path *mesh_path_lookup(u8 *dst, struct ieee80211_sub_if_data *sdata)
 {
-        struct mesh_path *mpath;
-        struct hlist_node *n;
-        struct hlist_head *bucket;
-        struct mesh_table *tbl;
-        struct mpath_node *node;
-
-        tbl = rcu_dereference(mpp_paths);
+        return path_lookup(rcu_dereference(mesh_paths), dst, sdata);
+}
 
-        bucket = &tbl->hash_buckets[mesh_table_hash(dst, sdata, tbl)];
-        hlist_for_each_entry_rcu(node, n, bucket, list) {
-                mpath = node->mpath;
-                if (mpath->sdata == sdata &&
-                    memcmp(dst, mpath->dst, ETH_ALEN) == 0) {
-                        if (MPATH_EXPIRED(mpath)) {
-                                spin_lock_bh(&mpath->state_lock);
-                                mpath->flags &= ~MESH_PATH_ACTIVE;
-                                spin_unlock_bh(&mpath->state_lock);
-                        }
-                        return mpath;
-                }
-        }
-        return NULL;
+struct mesh_path *mpp_path_lookup(u8 *dst, struct ieee80211_sub_if_data *sdata)
+{
+        return path_lookup(rcu_dereference(mpp_paths), dst, sdata);
 }
 
 
@@ -836,7 +818,8 @@ void mesh_path_flush_by_nexthop(struct sta_info *sta)
         int i;
 
         rcu_read_lock();
-        tbl = rcu_dereference(mesh_paths);
+        read_lock_bh(&pathtbl_resize_lock);
+        tbl = resize_dereference_mesh_paths();
         for_each_mesh_entry(tbl, p, node, i) {
                 mpath = node->mpath;
                 if (rcu_dereference(mpath->next_hop) == sta) {
@@ -845,6 +828,7 @@ void mesh_path_flush_by_nexthop(struct sta_info *sta)
                         spin_unlock_bh(&tbl->hashwlock[i]);
                 }
         }
+        read_unlock_bh(&pathtbl_resize_lock);
         rcu_read_unlock();
 }
 
@@ -880,10 +864,12 @@ void mesh_path_flush_by_iface(struct ieee80211_sub_if_data *sdata)
         struct mesh_table *tbl;
 
         rcu_read_lock();
-        tbl = rcu_dereference(mesh_paths);
+        read_lock_bh(&pathtbl_resize_lock);
+        tbl = resize_dereference_mesh_paths();
         table_flush_by_iface(tbl, sdata);
-        tbl = rcu_dereference(mpp_paths);
+        tbl = resize_dereference_mpp_paths();
         table_flush_by_iface(tbl, sdata);
+        read_unlock_bh(&pathtbl_resize_lock);
         rcu_read_unlock();
 }