net/ipv4/igmp.c: Replace rcu_dereference() with rcu_access_pointer()

The "rcu_dereference()" call is used directly in a condition. Since its return value is never dereferenced it is recommended to use "rcu_access_pointer()" instead of "rcu_dereference()". Therefore, this patch makes the replacement.

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

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

---
 net/ipv4/igmp.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

index 6748d42..94a96ad 100644
@@ -2537,7 +2537,7 @@ static int igmp_mc_seq_show(struct seq_file *seq, void *v)
 		querier = "NONE";
 #endif
 
-		if (rcu_dereference(state->in_dev->mc_list) == im) {
+		if (rcu_access_pointer(state->in_dev->mc_list) == im) {
 			seq_printf(seq, "%d\t%-10s: %5d %7s\n",
 				   state->dev->ifindex, state->dev->name, state->in_dev->mc_count, querier);
 		}

1.9.1

From: Andreea-Cristina Bernat <[email protected]>
Date: Sun, 17 Aug 2014 15:49:41 +0300

...

Applied.