[PATCH 30/47] kernel: Use RCU_INIT_POINTER(x, NULL) in events/core.c

[Monam Agarwal]

This patch replaces rcu_assign_pointer(x, NULL) with RCU_INIT_POINTER(x, NULL)

The rcu_assign_pointer() ensures that the initialization of a structure       
is carried out before storing a pointer to that structure. 
And in the case of the NULL pointer, there is no structure to initialize. 
So, rcu_assign_pointer(p, NULL) can be safely converted to RCU_INIT_POINTER(p, 
NULL)

Signed-off-by: Monam Agarwal <monamagarwal...@gmail.com>
---
 kernel/events/core.c |    8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/kernel/events/core.c b/kernel/events/core.c
index fa0b2d4..8c22758 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -3247,7 +3247,7 @@ static void free_event(struct perf_event *event)
                mutex_lock(&event->mmap_mutex);
                rb = event->rb;
                if (rb) {
-                       rcu_assign_pointer(event->rb, NULL);
+                       RCU_INIT_POINTER(event->rb, NULL);
                        ring_buffer_detach(event, rb);
                        ring_buffer_put(rb); /* could be last */
                }
@@ -3938,7 +3938,7 @@ static void perf_mmap_close(struct vm_area_struct *vma)
                return;
 
        /* Detach current event from the buffer. */
-       rcu_assign_pointer(event->rb, NULL);
+       RCU_INIT_POINTER(event->rb, NULL);
        ring_buffer_detach(event, rb);
        mutex_unlock(&event->mmap_mutex);
 
@@ -3977,7 +3977,7 @@ again:
                 * iterating the wrong list.
                 */
                if (event->rb == rb) {
-                       rcu_assign_pointer(event->rb, NULL);
+                       RCU_INIT_POINTER(event->rb, NULL);
                        ring_buffer_detach(event, rb);
                        ring_buffer_put(rb); /* can't be last, we still have 
one */
                }
@@ -5690,7 +5690,7 @@ static void swevent_hlist_release(struct swevent_htable 
*swhash)
        if (!hlist)
                return;
 
-       rcu_assign_pointer(swhash->swevent_hlist, NULL);
+       RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
        kfree_rcu(hlist, rcu_head);
 }
 
-- 
1.7.9.5

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