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 431865a..751c4d0 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;