From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753844AbaBQVgL (ORCPT ); Mon, 17 Feb 2014 16:36:11 -0500 Received: from e31.co.us.ibm.com ([32.97.110.149]:58655 "EHLO e31.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753501AbaBQVgI (ORCPT ); Mon, 17 Feb 2014 16:36:08 -0500 From: "Paul E. McKenney" To: linux-kernel@vger.kernel.org Cc: mingo@kernel.org, laijs@cn.fujitsu.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@efficios.com, josh@joshtriplett.org, niv@us.ibm.com, tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com, darren@dvhart.com, fweisbec@gmail.com, oleg@redhat.com, sbw@mit.edu, "Paul E. McKenney" , Alexander Viro , linux-fsdevel@vger.kernel.org Subject: [PATCH tip/core/rcu 09/12] fs: Substitute rcu_access_pointer() for rcu_dereference_raw() Date: Mon, 17 Feb 2014 13:35:56 -0800 Message-Id: <1392672959-6386-9-git-send-email-paulmck@linux.vnet.ibm.com> X-Mailer: git-send-email 1.8.1.5 In-Reply-To: <1392672959-6386-1-git-send-email-paulmck@linux.vnet.ibm.com> References: <20140217213533.GA5387@linux.vnet.ibm.com> <1392672959-6386-1-git-send-email-paulmck@linux.vnet.ibm.com> X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 14021721-8236-0000-0000-0000074EED31 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: "Paul E. McKenney" (Trivial patch.) If the code is looking at the RCU-protected pointer itself, but not dereferencing it, the rcu_dereference() functions can be downgraded to rcu_access_pointer(). This commit makes this downgrade in __alloc_fd(), which simply compares the RCU-protected pointer against NULL with no dereferencing. Signed-off-by: Paul E. McKenney Cc: Alexander Viro Cc: linux-fsdevel@vger.kernel.org --- fs/file.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/file.c b/fs/file.c index db25c2bdfe46..18f7d27855c4 100644 --- a/fs/file.c +++ b/fs/file.c @@ -497,7 +497,7 @@ repeat: error = fd; #if 1 /* Sanity check */ - if (rcu_dereference_raw(fdt->fd[fd]) != NULL) { + if (rcu_access_pointer(fdt->fd[fd]) != NULL) { printk(KERN_WARNING "alloc_fd: slot %d not NULL!\n", fd); rcu_assign_pointer(fdt->fd[fd], NULL); } -- 1.8.1.5