perf/callchain: Replace rcu_assign_pointer() with RCU_INIT_POINTER()
The use of "rcu_assign_pointer()" is NULLing out the pointer.
According to RCU_INIT_POINTER()'s block comment:
"1. This use of RCU_INIT_POINTER() is NULLing out the pointer"
it is better to use it instead of rcu_assign_pointer() because it has a
smaller overhead.
The following Coccinelle semantic patch was used:
@@
@@
- rcu_assign_pointer
+ RCU_INIT_POINTER
(..., NULL)
Signed-off-by: Andreea-Cristina Bernat <bernat.ada@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: paulmck@linux.vnet.ibm.com
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Link: http://lkml.kernel.org/r/20140822141536.GA32051@ada
Signed-off-by: Ingo Molnar <mingo@kernel.org>
diff --git a/kernel/events/callchain.c b/kernel/events/callchain.c
index 97b67df..f2a88de 100644
--- a/kernel/events/callchain.c
+++ b/kernel/events/callchain.c
@@ -52,7 +52,7 @@
struct callchain_cpus_entries *entries;
entries = callchain_cpus_entries;
- rcu_assign_pointer(callchain_cpus_entries, NULL);
+ RCU_INIT_POINTER(callchain_cpus_entries, NULL);
call_rcu(&entries->rcu_head, release_callchain_buffers_rcu);
}