[PATCH] drivers/input: Use RCU_INIT_POINTER(x, NULL) in evdev.c

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 <redacted>
---
 drivers/input/evdev.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/input/evdev.c b/drivers/input/evdev.c
index a06e125..fffa107 100644
--- a/drivers/input/evdev.c
+++ b/drivers/input/evdev.c

@@ -291,7 +291,7 @@ static int evdev_ungrab(struct evdev *evdev, struct evdev_client *client)
 	if (grab != client)
 		return  -EINVAL;
 
-	rcu_assign_pointer(evdev->grab, NULL);
+	RCU_INIT_POINTER(evdev->grab, NULL);
 	synchronize_rcu();
 	input_release_device(&evdev->handle);
 

-- 
1.7.9.5

Hi Monam,

On Sun, Mar 23, 2014 at 11:56:17PM +0530, Monam Agarwal wrote:

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)

Logically speaking we perform assignment, not initialization there.
Since we are not in hot path I think we should leave the code as is.

Thanks.

-- 
Dmitry