2014-08-17 13:18:10

by Andreea Bernat

Subject: [PATCH] mac80211: Replace rcu_dereference() with rcu_access_pointer()

The "rcu_dereference()" calls are used directly in conditions.
Since their return values are never dereferenced it is recommended to
use "rcu_access_pointer()" instead of "rcu_dereference()".
Therefore, this patch makes the replacements.

The following Coccinelle semantic patch was used:
@@
@@

(
if(
(<+...
- rcu_dereference
+ rcu_access_pointer
(...)
...+>)) {...}
|
while(
(<+...
- rcu_dereference
+ rcu_access_pointer
(...)
...+>)) {...}
)

Signed-off-by: Andreea-Cristina Bernat <[email protected]>
---
net/mac80211/mesh_pathtbl.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/mac80211/mesh_pathtbl.c b/net/mac80211/mesh_pathtbl.c
index cf032a8..a6699dc 100644
--- a/net/mac80211/mesh_pathtbl.c
+++ b/net/mac80211/mesh_pathtbl.c
@@ -729,7 +729,7 @@ void mesh_plink_broken(struct sta_info *sta)
tbl = rcu_dereference(mesh_paths);
for_each_mesh_entry(tbl, node, i) {
mpath = node->mpath;
- if (rcu_dereference(mpath->next_hop) == sta &&
+ if (rcu_access_pointer(mpath->next_hop) == sta &&
mpath->flags & MESH_PATH_ACTIVE &&
!(mpath->flags & MESH_PATH_FIXED)) {
spin_lock_bh(&mpath->state_lock);
@@ -794,7 +794,7 @@ void mesh_path_flush_by_nexthop(struct sta_info *sta)
tbl = resize_dereference_mesh_paths();
for_each_mesh_entry(tbl, node, i) {
mpath = node->mpath;
- if (rcu_dereference(mpath->next_hop) == sta) {
+ if (rcu_access_pointer(mpath->next_hop) == sta) {
spin_lock(&tbl->hashwlock[i]);
__mesh_path_del(tbl, node);
spin_unlock(&tbl->hashwlock[i]);
--
1.9.1

2014-08-27 10:14:35

by Johannes Berg

Subject: Re: [PATCH] mac80211: Replace rcu_dereference() with rcu_access_pointer()

On Sun, 2014-08-17 at 16:18 +0300, Andreea-Cristina Bernat wrote:
> The "rcu_dereference()" calls are used directly in conditions.
> Since their return values are never dereferenced it is recommended to
> use "rcu_access_pointer()" instead of "rcu_dereference()".
> Therefore, this patch makes the replacements.

Applied, thanks.

johannes