mac80211: Move mpath and mpp growth to mesh workqueue.

This prevents calling rcu_synchronize from within the tx path by moving the
table growth code to the mesh workqueue.

Move mesh_table_free and mesh_table_grow from mesh.c to mesh_pathtbl.c and
declare them static.

Also, re-enable mesh in Kconfig and update the configuration description.

Signed-off-by: Javier Cardona <javier@cozybit.com>
Tested-by: Andrey Yurovsky <andrey@cozybit.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 110 insertions, 36 deletions

diff --git a/net/mac80211/mesh_pathtbl.c b/net/mac80211/mesh_pathtbl.c
index 431865a58622..751c4d0e2b36 100644
--- a/net/mac80211/mesh_pathtbl.c
+++ b/net/mac80211/mesh_pathtbl.c
@@ -39,6 +39,69 @@ static struct mesh_table *mesh_paths;
 static struct mesh_table *mpp_paths; /* Store paths for MPP&MAP */
 
 int mesh_paths_generation;
+static void __mesh_table_free(struct mesh_table *tbl)
+{
+        kfree(tbl->hash_buckets);
+        kfree(tbl->hashwlock);
+        kfree(tbl);
+}
+
+void mesh_table_free(struct mesh_table *tbl, bool free_leafs)
+{
+        struct hlist_head *mesh_hash;
+        struct hlist_node *p, *q;
+        int i;
+
+        mesh_hash = tbl->hash_buckets;
+        for (i = 0; i <= tbl->hash_mask; i++) {
+                spin_lock(&tbl->hashwlock[i]);
+                hlist_for_each_safe(p, q, &mesh_hash[i]) {
+                        tbl->free_node(p, free_leafs);
+                        atomic_dec(&tbl->entries);
+                }
+                spin_unlock(&tbl->hashwlock[i]);
+        }
+        __mesh_table_free(tbl);
+}
+
+static struct mesh_table *mesh_table_grow(struct mesh_table *tbl)
+{
+        struct mesh_table *newtbl;
+        struct hlist_head *oldhash;
+        struct hlist_node *p, *q;
+        int i;
+
+        if (atomic_read(&tbl->entries)
+                        < tbl->mean_chain_len * (tbl->hash_mask + 1))
+                goto endgrow;
+
+        newtbl = mesh_table_alloc(tbl->size_order + 1);
+        if (!newtbl)
+                goto endgrow;
+
+        newtbl->free_node = tbl->free_node;
+        newtbl->mean_chain_len = tbl->mean_chain_len;
+        newtbl->copy_node = tbl->copy_node;
+        atomic_set(&newtbl->entries, atomic_read(&tbl->entries));
+
+        oldhash = tbl->hash_buckets;
+        for (i = 0; i <= tbl->hash_mask; i++)
+                hlist_for_each(p, &oldhash[i])
+                        if (tbl->copy_node(p, newtbl) < 0)
+                                goto errcopy;
+
+        return newtbl;
+
+errcopy:
+        for (i = 0; i <= newtbl->hash_mask; i++) {
+                hlist_for_each_safe(p, q, &newtbl->hash_buckets[i])
+                        tbl->free_node(p, 0);
+        }
+        __mesh_table_free(newtbl);
+endgrow:
+        return NULL;
+}
+
 
 /* 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
@@ -187,6 +250,8 @@ struct mesh_path *mesh_path_lookup_by_idx(int idx, struct ieee80211_sub_if_data
  */
 int mesh_path_add(u8 *dst, struct ieee80211_sub_if_data *sdata)
 {
+        struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
+        struct ieee80211_local *local = sdata->local;
         struct mesh_path *mpath, *new_mpath;
         struct mpath_node *node, *new_node;
         struct hlist_head *bucket;
@@ -195,8 +260,6 @@ int mesh_path_add(u8 *dst, struct ieee80211_sub_if_data *sdata)
         int err = 0;
         u32 hash_idx;
 
-        might_sleep();
-
         if (memcmp(dst, sdata->dev->dev_addr, ETH_ALEN) == 0)
                 /* never add ourselves as neighbours */
                 return -ENOTSUPP;
@@ -208,11 +271,11 @@ int mesh_path_add(u8 *dst, struct ieee80211_sub_if_data *sdata)
                 return -ENOSPC;
 
         err = -ENOMEM;
-        new_mpath = kzalloc(sizeof(struct mesh_path), GFP_KERNEL);
+        new_mpath = kzalloc(sizeof(struct mesh_path), GFP_ATOMIC);
         if (!new_mpath)
                 goto err_path_alloc;
 
-        new_node = kmalloc(sizeof(struct mpath_node), GFP_KERNEL);
+        new_node = kmalloc(sizeof(struct mpath_node), GFP_ATOMIC);
         if (!new_node)
                 goto err_node_alloc;
 
@@ -250,20 +313,8 @@ int mesh_path_add(u8 *dst, struct ieee80211_sub_if_data *sdata)
         spin_unlock(&mesh_paths->hashwlock[hash_idx]);
         read_unlock(&pathtbl_resize_lock);
         if (grow) {
-                struct mesh_table *oldtbl, *newtbl;
-
-                write_lock(&pathtbl_resize_lock);
-                oldtbl = mesh_paths;
-                newtbl = mesh_table_grow(mesh_paths);
-                if (!newtbl) {
-                        write_unlock(&pathtbl_resize_lock);
-                        return 0;
-                }
-                rcu_assign_pointer(mesh_paths, newtbl);
-                write_unlock(&pathtbl_resize_lock);
-
-                synchronize_rcu();
-                mesh_table_free(oldtbl, false);
+                set_bit(MESH_WORK_GROW_MPATH_TABLE,  &ifmsh->wrkq_flags);
+                ieee80211_queue_work(&local->hw, &ifmsh->work);
         }
         return 0;
 
@@ -278,9 +329,46 @@ err_path_alloc:
         return err;
 }
 
+void mesh_mpath_table_grow(void)
+{
+        struct mesh_table *oldtbl, *newtbl;
+
+        write_lock(&pathtbl_resize_lock);
+        oldtbl = mesh_paths;
+        newtbl = mesh_table_grow(mesh_paths);
+        if (!newtbl) {
+                write_unlock(&pathtbl_resize_lock);
+                return;
+        }
+        rcu_assign_pointer(mesh_paths, newtbl);
+        write_unlock(&pathtbl_resize_lock);
+
+        synchronize_rcu();
+        mesh_table_free(oldtbl, false);
+}
+
+void mesh_mpp_table_grow(void)
+{
+        struct mesh_table *oldtbl, *newtbl;
+
+        write_lock(&pathtbl_resize_lock);
+        oldtbl = mpp_paths;
+        newtbl = mesh_table_grow(mpp_paths);
+        if (!newtbl) {
+                write_unlock(&pathtbl_resize_lock);
+                return;
+        }
+        rcu_assign_pointer(mpp_paths, newtbl);
+        write_unlock(&pathtbl_resize_lock);
+
+        synchronize_rcu();
+        mesh_table_free(oldtbl, false);
+}
 
 int mpp_path_add(u8 *dst, u8 *mpp, struct ieee80211_sub_if_data *sdata)
 {
+        struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
+        struct ieee80211_local *local = sdata->local;
         struct mesh_path *mpath, *new_mpath;
         struct mpath_node *node, *new_node;
         struct hlist_head *bucket;
@@ -289,8 +377,6 @@ int mpp_path_add(u8 *dst, u8 *mpp, struct ieee80211_sub_if_data *sdata)
         int err = 0;
         u32 hash_idx;
 
-        might_sleep();
-
         if (memcmp(dst, sdata->dev->dev_addr, ETH_ALEN) == 0)
                 /* never add ourselves as neighbours */
                 return -ENOTSUPP;
@@ -299,11 +385,11 @@ int mpp_path_add(u8 *dst, u8 *mpp, struct ieee80211_sub_if_data *sdata)
                 return -ENOTSUPP;
 
         err = -ENOMEM;
-        new_mpath = kzalloc(sizeof(struct mesh_path), GFP_KERNEL);
+        new_mpath = kzalloc(sizeof(struct mesh_path), GFP_ATOMIC);
         if (!new_mpath)
                 goto err_path_alloc;
 
-        new_node = kmalloc(sizeof(struct mpath_node), GFP_KERNEL);
+        new_node = kmalloc(sizeof(struct mpath_node), GFP_ATOMIC);
         if (!new_node)
                 goto err_node_alloc;
 
@@ -337,20 +423,8 @@ int mpp_path_add(u8 *dst, u8 *mpp, struct ieee80211_sub_if_data *sdata)
         spin_unlock(&mpp_paths->hashwlock[hash_idx]);
         read_unlock(&pathtbl_resize_lock);
         if (grow) {
-                struct mesh_table *oldtbl, *newtbl;
-
-                write_lock(&pathtbl_resize_lock);
-                oldtbl = mpp_paths;
-                newtbl = mesh_table_grow(mpp_paths);
-                if (!newtbl) {
-                        write_unlock(&pathtbl_resize_lock);
-                        return 0;
-                }
-                rcu_assign_pointer(mpp_paths, newtbl);
-                write_unlock(&pathtbl_resize_lock);
-
-                synchronize_rcu();
-                mesh_table_free(oldtbl, false);
+                set_bit(MESH_WORK_GROW_MPP_TABLE,  &ifmsh->wrkq_flags);
+                ieee80211_queue_work(&local->hw, &ifmsh->work);
         }
         return 0;