From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756327AbaJWQaZ (ORCPT ); Thu, 23 Oct 2014 12:30:25 -0400 Received: from mail-pa0-f49.google.com ([209.85.220.49]:60091 "EHLO mail-pa0-f49.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751614AbaJWQaX (ORCPT ); Thu, 23 Oct 2014 12:30:23 -0400 Message-ID: <54492D1F.3080005@kernel.dk> Date: Thu, 23 Oct 2014 10:30:23 -0600 From: Jens Axboe User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.2.0 MIME-Version: 1.0 To: Sudip Mukherjee CC: linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] block: wrong return value References: <1414080271-6551-1-git-send-email-sudipm.mukherjee@gmail.com> <54492840.9050704@kernel.dk> <20141023162859.GB6590@sudip-PC> In-Reply-To: <20141023162859.GB6590@sudip-PC> 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 10/23/2014 10:28 AM, Sudip Mukherjee wrote: > On Thu, Oct 23, 2014 at 10:09:36AM -0600, Jens Axboe wrote: >> On 10/23/2014 10:04 AM, Sudip Mukherjee wrote: >>> while compiling integer err was showing as a set but unused variable. >>> elevator_init_fn can be either cfq_init_queue or deadline_init_queue >>> or noop_init_queue. >>> all three of these functions are returning -ENOMEM if they fail to >>> allocate the queue. >>> so we should actually be returning the error code rather than >>> returning 0 always. >>> >>> Signed-off-by: Sudip Mukherjee >>> --- >>> >>> change in v2: added elevator_put >>> >>> block/elevator.c | 6 ++++-- >>> 1 file changed, 4 insertions(+), 2 deletions(-) >>> >>> diff --git a/block/elevator.c b/block/elevator.c >>> index 24c28b6..1267c2b 100644 >>> --- a/block/elevator.c >>> +++ b/block/elevator.c >>> @@ -184,7 +184,7 @@ static void elevator_release(struct kobject *kobj) >>> int elevator_init(struct request_queue *q, char *name) >>> { >>> struct elevator_type *e = NULL; >>> - int err; >>> + int err = 0; >> >> Why init it to 0? > not required actually. my initial thinking was that we are returning 0 on success or else the error code. so gave it a default value of 0. > but elevator_init_fn is returning 0 on success , so we will get 0 even if we do not initialize it. > should i resend after modifying it? Yes resend it please, the assignment is meaningless as it is overwritten later before being used. -- Jens Axboe