Re: [PATCH 2/2] mac80211: mesh: convert path table to rhashtable

[Johannes Berg]

On Wed, 2016-03-02 at 14:43 -0500, David Miller wrote:
> From: Bob Copeland 
> Date: Wed,  2 Mar 2016 10:09:20 -0500
> 
> > In the time since the mesh path table was implemented as an
> > RCU-traversable, dynamically growing hash table, a generic RCU
> > hashtable implementation was added to the kernel.
> > 
> > Switch the mesh path table over to rhashtable to remove some code
> > and also gain some features like automatic shrinking.
> > 
> > Cc: Thomas Graf 
> > Cc: netdev@vger.kernel.org
> > Signed-off-by: Bob Copeland 
> 
> Johannes, feel free to take both patches via your tree, thanks.

Will do, thanks.

johannes

Re: [PATCH 2/2] mac80211: mesh: convert path table to rhashtable

[David Miller]

From: Bob Copeland 
Date: Wed,  2 Mar 2016 10:09:20 -0500

> In the time since the mesh path table was implemented as an
> RCU-traversable, dynamically growing hash table, a generic RCU
> hashtable implementation was added to the kernel.
> 
> Switch the mesh path table over to rhashtable to remove some code
> and also gain some features like automatic shrinking.
> 
> Cc: Thomas Graf 
> Cc: netdev@vger.kernel.org
> Signed-off-by: Bob Copeland 

Johannes, feel free to take both patches via your tree, thanks.

[PATCH 2/2] mac80211: mesh: convert path table to rhashtable

[Bob Copeland]

In the time since the mesh path table was implemented as an
RCU-traversable, dynamically growing hash table, a generic RCU
hashtable implementation was added to the kernel.

Switch the mesh path table over to rhashtable to remove some code
and also gain some features like automatic shrinking.

Cc: Thomas Graf 
Cc: netdev@vger.kernel.org
Signed-off-by: Bob Copeland 
---
 net/mac80211/ieee80211_i.h  |  11 +-
 net/mac80211/mesh.c |   6 -
 net/mac80211/mesh.h |  31 +-
 net/mac80211/mesh_pathtbl.c | 786 ++--
 4 files changed, 259 insertions(+), 575 deletions(-)

diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index db7f0dbebc4b..c8945e2d8a86 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -697,17 +697,10 @@ 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 */
+   struct mesh_table *mesh_paths;
+   struct mesh_table *mpp_paths; /* Store paths for MPP */
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
diff --git a/net/mac80211/mesh.c b/net/mac80211/mesh.c
index c92af2a7714d..a216c439b6f2 100644
--- a/net/mac80211/mesh.c
+++ b/net/mac80211/mesh.c
@@ -1347,12 +1347,6 @@ void ieee80211_mesh_work(struct ieee80211_sub_if_data 
*sdata)
   ifmsh->last_preq + 
msecs_to_jiffies(ifmsh->mshcfg.dot11MeshHWMPpreqMinInterval)))
mesh_path_start_discovery(sdata);
 
-   if (test_and_clear_bit(MESH_WORK_GROW_MPATH_TABLE, >wrkq_flags))
-   mesh_mpath_table_grow(sdata);
-
-   if (test_and_clear_bit(MESH_WORK_GROW_MPP_TABLE, >wrkq_flags))
-   mesh_mpp_table_grow(sdata);
-
if (test_and_clear_bit(MESH_WORK_HOUSEKEEPING, >wrkq_flags))
ieee80211_mesh_housekeeping(sdata);
 
diff --git a/net/mac80211/mesh.h b/net/mac80211/mesh.h
index f3cc3917e048..cc6854db156e 100644
--- a/net/mac80211/mesh.h
+++ b/net/mac80211/mesh.h
@@ -51,10 +51,6 @@ enum mesh_path_flags {
  *
  *
  * @MESH_WORK_HOUSEKEEPING: run the periodic mesh housekeeping tasks
- * @MESH_WORK_GROW_MPATH_TABLE: the mesh path table is full and needs
- * to grow.
- * @MESH_WORK_GROW_MPP_TABLE: the mesh portals table is full and needs to
- * grow
  * @MESH_WORK_ROOT: the mesh root station needs to send a frame
  * @MESH_WORK_DRIFT_ADJUST: time to compensate for clock drift relative to 
other
  * mesh nodes
@@ -62,8 +58,6 @@ enum mesh_path_flags {
  */
 enum mesh_deferred_task_flags {
MESH_WORK_HOUSEKEEPING,
-   MESH_WORK_GROW_MPATH_TABLE,
-   MESH_WORK_GROW_MPP_TABLE,
MESH_WORK_ROOT,
MESH_WORK_DRIFT_ADJUST,
MESH_WORK_MBSS_CHANGED,
@@ -105,6 +99,7 @@ enum mesh_deferred_task_flags {
 struct mesh_path {
u8 dst[ETH_ALEN];
u8 mpp[ETH_ALEN];   /* used for MPP or MAP */
+   struct rhash_head rhash;
struct hlist_node gate_list;
struct ieee80211_sub_if_data *sdata;
struct sta_info __rcu *next_hop;
@@ -129,34 +124,17 @@ struct mesh_path {
 /**
  * struct mesh_table
  *
- * @hash_buckets: array of hash buckets of the table
- * @hashwlock: array of locks to protect write operations, one per bucket
- * @hash_mask: 2^size_order - 1, used to compute hash idx
- * @hash_rnd: random value used for hash computations
  * @entries: number of entries in the table
- * @free_node: function to free nodes of the table
- * @copy_node: function to copy nodes of the table
- * @size_order: determines size of the table, there will be 2^size_order hash
- * buckets
  * @known_gates: list of known mesh gates and their mpaths by the station. The
  * gate's mpath may or may not be resolved and active.
- *
- * rcu_head: RCU head to free the table
+ * @rhash: the rhashtable containing struct mesh_paths, keyed by dest addr
  */
 struct mesh_table {
-   /* Number of buckets will be 2^N */
-   struct hlist_head *hash_buckets;
-   spinlock_t *hashwlock;  /* One per bucket, for add/del */
-   unsigned int hash_mask; /* (2^size_order) - 1 */
-   __u32 hash_rnd; /* Used for hash generation */
atomic_t entries;   /* Up to MAX_MESH_NEIGHBOURS */
-   void (*free_node) (struct hlist_node *p, bool free_leafs);
-   int (*copy_node) (struct hlist_node *p, struct mesh_table *newtbl);
-   int size_order;
struct hlist_head *known_gates;
spinlock_t gates_lock;
 
-   struct rcu_head rcu_head;
+   struct rhashtable rhead;