[PATCH] net: core: neighbour: Replace rcu_assign_pointer() with RCU_INIT_POINTER()

From: Andreea-Cristina Bernat
Date: Tue Aug 26 2014 - 10:27:19 EST


According to RCU_INIT_POINTER()'s block comment 3.a, it can be used if
"3. The referenced data structure has already been exposed to readers either
at compile time or via rcu_assign_pointer() -and-
a. You have not made -any- reader-visible changes to this structure since
then".

These cases fulfill the conditions above because between the
rcu_dereference_protected() calls and the rcu_assign_pointer() calls there is
no update of those values.
Therefore, this patch makes the replacements.

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

- rcu_assign_pointer
+ RCU_INIT_POINTER
(...,
(
rtnl_dereference(...)
|
rcu_dereference_protected(...)
) )

Signed-off-by: Andreea-Cristina Bernat <bernat.ada@xxxxxxxxx>
---
net/core/neighbour.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/net/core/neighbour.c b/net/core/neighbour.c
index 32d872e..a193932 100644
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -147,7 +147,7 @@ static int neigh_forced_gc(struct neigh_table *tbl)
write_lock(&n->lock);
if (atomic_read(&n->refcnt) == 1 &&
!(n->nud_state & NUD_PERMANENT)) {
- rcu_assign_pointer(*np,
+ RCU_INIT_POINTER(*np,
rcu_dereference_protected(n->next,
lockdep_is_held(&tbl->lock)));
n->dead = 1;
@@ -216,7 +216,7 @@ static void neigh_flush_dev(struct neigh_table *tbl, struct net_device *dev)
np = &n->next;
continue;
}
- rcu_assign_pointer(*np,
+ RCU_INIT_POINTER(*np,
rcu_dereference_protected(n->next,
lockdep_is_held(&tbl->lock)));
write_lock(&n->lock);
@@ -386,7 +386,7 @@ static struct neigh_hash_table *neigh_hash_grow(struct neigh_table *tbl,
next = rcu_dereference_protected(n->next,
lockdep_is_held(&tbl->lock));

- rcu_assign_pointer(n->next,
+ RCU_INIT_POINTER(n->next,
rcu_dereference_protected(
new_nht->hash_buckets[hash],
lockdep_is_held(&tbl->lock)));
@@ -531,7 +531,7 @@ struct neighbour *__neigh_create(struct neigh_table *tbl, const void *pkey,
n->dead = 0;
if (want_ref)
neigh_hold(n);
- rcu_assign_pointer(n->next,
+ RCU_INIT_POINTER(n->next,
rcu_dereference_protected(nht->hash_buckets[hash_val],
lockdep_is_held(&tbl->lock)));
rcu_assign_pointer(nht->hash_buckets[hash_val], n);
@@ -2432,7 +2432,7 @@ void __neigh_for_each_release(struct neigh_table *tbl,
write_lock(&n->lock);
release = cb(n);
if (release) {
- rcu_assign_pointer(*np,
+ RCU_INIT_POINTER(*np,
rcu_dereference_protected(n->next,
lockdep_is_held(&tbl->lock)));
n->dead = 1;
--
1.9.1

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