From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755511Ab2DGTBY (ORCPT ); Sat, 7 Apr 2012 15:01:24 -0400 Received: from mail-wi0-f178.google.com ([209.85.212.178]:45361 "EHLO mail-wi0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755351Ab2DGTBU (ORCPT ); Sat, 7 Apr 2012 15:01:20 -0400 Date: Sat, 7 Apr 2012 22:01:17 +0300 From: Alexey Dobriyan To: akpm@linux-foundation.org Cc: linux-kernel@vger.kernel.org Subject: [PATCH 1/2] proc: don't do dummy rcu_read_lock/rcu_read_unlock on error path Message-ID: <20120407190117.GA5946@p183.telecom.by> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org rcu_read_lock()/rcu_read_unlock() is nop for TINY_RCU, but is not a nop for, say, PREEMPT_RCU. proc_fill_cache() is called without RCU lock, there is no need to lock/unlock on error path, simply jump out of the loop. Signed-off-by: Alexey Dobriyan --- fs/proc/base.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -1943,21 +1943,22 @@ static int proc_readfd_common(struct file * filp, void * dirent, fd++, filp->f_pos++) { char name[PROC_NUMBUF]; int len; + int rv; if (!fcheck_files(files, fd)) continue; rcu_read_unlock(); len = snprintf(name, sizeof(name), "%d", fd); - if (proc_fill_cache(filp, dirent, filldir, - name, len, instantiate, - p, &fd) < 0) { - rcu_read_lock(); - break; - } + rv = proc_fill_cache(filp, dirent, filldir, + name, len, instantiate, p, + &fd); + if (rv < 0) + goto out_fd_loop; rcu_read_lock(); } rcu_read_unlock(); +out_fd_loop: put_files_struct(files); } out: