[PATCH] kernel/events/core.c: Replace rcu_dereference() with rcu_access_pointer()

From: Andreea-Cristina Bernat
Date: Sun Aug 17 2014 - 08:34:45 EST


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
(...)
...+>)) {...}
)

Signed-off-by: Andreea-Cristina Bernat <bernat.ada@xxxxxxxxx>
---
kernel/events/core.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 5fa58e4..0d735be 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -980,7 +980,7 @@ retry:
* can't get swapped on us any more.
*/
raw_spin_lock_irqsave(&ctx->lock, *flags);
- if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
+ if (ctx != rcu_access_pointer(task->perf_event_ctxp[ctxn])) {
raw_spin_unlock_irqrestore(&ctx->lock, *flags);
rcu_read_unlock();
preempt_enable();
--
1.9.1

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