[PATCH] evdev: Replace rcu_assign_pointer() with RCU_INIT_POINTER()

Subsystems: input (keyboard, mouse, joystick, touchscreen) drivers, the rest

STALE4376d

2 messages, 2 authors, 2014-08-18 · open the first message on its own page

[PATCH] evdev: Replace rcu_assign_pointer() with RCU_INIT_POINTER()

From: Andreea-Cristina Bernat <hidden>
Date: 2014-08-18 14:44:59

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 <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 fd325ec..33e53a7 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);
 
-- 
1.9.1

Re: [PATCH] evdev: Replace rcu_assign_pointer() with RCU_INIT_POINTER()

From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Date: 2014-08-18 18:41:37

Hi Andreea,

On Mon, Aug 18, 2014 at 05:44:45PM +0300, Andreea-Cristina Bernat wrote:
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)
The same objection as here: https://lkml.org/lkml/2014/3/23/96

Thanks.

-- 
Dmitry
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