From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dmitry Torokhov Subject: Re: [PATCH] drivers/input: Use RCU_INIT_POINTER(x, NULL) in evdev.c Date: Wed, 26 Mar 2014 13:30:05 -0700 Message-ID: <20140326203005.GC11013@core.coreip.homeip.net> References: <1395599177-6776-1-git-send-email-monamagarwal123@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mail-pb0-f53.google.com ([209.85.160.53]:42829 "EHLO mail-pb0-f53.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755989AbaCZUaI (ORCPT ); Wed, 26 Mar 2014 16:30:08 -0400 Content-Disposition: inline In-Reply-To: <1395599177-6776-1-git-send-email-monamagarwal123@gmail.com> Sender: linux-input-owner@vger.kernel.org List-Id: linux-input@vger.kernel.org To: Monam Agarwal Cc: linux-input@vger.kernel.org, linux-kernel@vger.kernel.org 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. > > Signed-off-by: Monam Agarwal > --- > 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 > -- Dmitry