From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751344AbcFAXnZ (ORCPT ); Wed, 1 Jun 2016 19:43:25 -0400 Received: from lists.s-osg.org ([54.187.51.154]:35802 "EHLO lists.s-osg.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750824AbcFAXnZ (ORCPT ); Wed, 1 Jun 2016 19:43:25 -0400 Message-ID: <574F7317.3030802@osg.samsung.com> Date: Thu, 02 Jun 2016 00:43:19 +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: Andrew Morton CC: linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk, fabf@skynet.be Subject: Re: [PATCH] befs/btree: remove unneeded initializations References: <1464568799-12631-1-git-send-email-luisbg@osg.samsung.com> <20160601154240.3bb9760d518af5bc95548016@linux-foundation.org> In-Reply-To: <20160601154240.3bb9760d518af5bc95548016@linux-foundation.org> 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 01/06/16 23:42, Andrew Morton wrote: > On Mon, 30 May 2016 01:39:59 +0100 Luis de Bethencourt wrote: > >> off in befs_bt_read_node() will be written by befs_read_datastream(), with >> the value that node->od_node needs. >> >> node_off in befs_btree_read() isn't read before set to root_node_ptr. >> >> Removing these two unneeded initializations. >> >> ... >> >> --- a/fs/befs/btree.c >> +++ b/fs/befs/btree.c >> @@ -196,7 +196,7 @@ static int >> befs_bt_read_node(struct super_block *sb, const befs_data_stream *ds, >> struct befs_btree_node *node, befs_off_t node_off) >> { >> - uint off = 0; >> + uint off; >> >> befs_debug(sb, "---> %s", __func__); >> > > With this code: > > int foo; > > bar(&foo); > > whatever = foo; > > some versions of gcc will warn that foo might be used uninitialized. > Other versions of gcc don't do this. That's why the seemingly-unneeded > initializations are there. > > Neither of the versions of gcc which I tested with actually do warn, > but I'm inclined to leave things as-is: some people will get warnings > and that's probably worse than a couple of bytes bloat in befs. > > It shouldn't cause any bloat, really. We have the "uninitialized_var" > macro which avoids any bloat and is self-documenting. And the nice > thing about self-documenting code is that it prevents Andrew from > having to explain strange code to Luis ;) But unintialized_var in > unpopular for reasons which I personally find unpersuasive, given > the advantages... > I understand. Let's keep the code as it is. Not worth adding uninitialized_var() for that declaration. Even though they are self-documenting indeed. Is this also the case with the node_off declaration? Before being passed by reference to befs_btree_seekleaf() the initial value is overwritten with node_off = bt_super.root_node_ptr; Thanks for reviewing this, Luis