From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752767AbaJFVh6 (ORCPT ); Mon, 6 Oct 2014 17:37:58 -0400 Received: from cdptpa-outbound-snat.email.rr.com ([107.14.166.227]:58304 "EHLO cdptpa-oedge-vip.email.rr.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751809AbaJFVge (ORCPT ); Mon, 6 Oct 2014 17:36:34 -0400 Message-Id: <20141006213631.498529423@goodmis.org> User-Agent: quilt/0.61-1 Date: Mon, 06 Oct 2014 17:35:53 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Linus Torvalds , Ingo Molnar , Andrew Morton , Andreea-Cristina Bernat Subject: [PATCH 09/11] kernel: trace_syscalls: Replace rcu_assign_pointer() with RCU_INIT_POINTER() References: <20141006213544.344821619@goodmis.org> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Content-Disposition: inline; filename=0009-kernel-trace_syscalls-Replace-rcu_assign_pointer-wit.patch X-RR-Connecting-IP: 107.14.168.142:25 X-Cloudmark-Score: 0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Andreea-Cristina Bernat The uses of "rcu_assign_pointer()" are NULLing out the pointers. 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) Link: http://lkml.kernel.org/p/20140822142822.GA32391@ada Signed-off-by: Andreea-Cristina Bernat Signed-off-by: Steven Rostedt --- kernel/trace/trace_syscalls.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c index 759d5e004517..4dc8b79c5f75 100644 --- a/kernel/trace/trace_syscalls.c +++ b/kernel/trace/trace_syscalls.c @@ -425,7 +425,7 @@ static void unreg_event_syscall_enter(struct ftrace_event_file *file, return; mutex_lock(&syscall_trace_lock); tr->sys_refcount_enter--; - rcu_assign_pointer(tr->enter_syscall_files[num], NULL); + RCU_INIT_POINTER(tr->enter_syscall_files[num], NULL); if (!tr->sys_refcount_enter) unregister_trace_sys_enter(ftrace_syscall_enter, tr); mutex_unlock(&syscall_trace_lock); @@ -463,7 +463,7 @@ static void unreg_event_syscall_exit(struct ftrace_event_file *file, return; mutex_lock(&syscall_trace_lock); tr->sys_refcount_exit--; - rcu_assign_pointer(tr->exit_syscall_files[num], NULL); + RCU_INIT_POINTER(tr->exit_syscall_files[num], NULL); if (!tr->sys_refcount_exit) unregister_trace_sys_exit(ftrace_syscall_exit, tr); mutex_unlock(&syscall_trace_lock); -- 2.0.1