From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752393AbcGBLiZ (ORCPT ); Sat, 2 Jul 2016 07:38:25 -0400 Received: from ec2-52-27-115-49.us-west-2.compute.amazonaws.com ([52.27.115.49]:45433 "EHLO s-opensource.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752330AbcGBLiY (ORCPT ); Sat, 2 Jul 2016 07:38:24 -0400 Message-ID: <5777A7AA.4020500@osg.samsung.com> Date: Sat, 02 Jul 2016 12:38:18 +0100 From: Luis de Bethencourt User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Icedove/31.8.0 MIME-Version: 1.0 To: Salah Triki , akpm@linux-foundation.org, viro@zeniv.linux.org.uk CC: mhocko@suse.com, vdavydov@virtuozzo.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/4] fs: befs: Remove redundant validation from befs_find_brun_direct References: <9859a616787673d2f36ce21d4aa0220637c55001.1467446561.git.salah.triki@gmail.com> In-Reply-To: <9859a616787673d2f36ce21d4aa0220637c55001.1467446561.git.salah.triki@gmail.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 02/07/16 09:05, Salah Triki wrote: > The only caller of befs_find_brun_direct is befs_fblock2brun, which > already validates that the block is within the range of direct blocks. > So remove the duplicate validation. > > Signed-off-by: Salah Triki > --- > fs/befs/datastream.c | 8 -------- > 1 file changed, 8 deletions(-) > > diff --git a/fs/befs/datastream.c b/fs/befs/datastream.c > index 26cc417..e224b9a 100644 > --- a/fs/befs/datastream.c > +++ b/fs/befs/datastream.c > @@ -249,17 +249,9 @@ befs_find_brun_direct(struct super_block *sb, const befs_data_stream *data, > int i; > const befs_block_run *array = data->direct; > befs_blocknr_t sum; > - befs_blocknr_t max_block = > - data->max_direct_range >> BEFS_SB(sb)->block_shift; > > befs_debug(sb, "---> %s, find %lu", __func__, (unsigned long)blockno); > > - if (blockno > max_block) { > - befs_error(sb, "%s passed block outside of direct region", > - __func__); > - return BEFS_ERR; > - } > - > for (i = 0, sum = 0; i < BEFS_NUM_DIRECT_BLOCKS; > sum += array[i].len, i++) { > if (blockno >= sum && blockno < sum + (array[i].len)) { > Hi Salah, These aren't the same check though. If we ignore the BEFS_SB(sb)->block_shift just to comparing them, we can consider the checks to be the following. In befs_fblock2brun(): if (fblock < data->max_direct_range) In befs_find_brun_direct(): if (fblock > data->max_direct_range) Notice how one checks if the block is past the range, and the other checks if it isn't before it. They also looked similar to me the first time I saw them and I had to double-check :) Thanks, Luis