From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0F20BC433F5 for ; Thu, 31 Mar 2022 10:49:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234733AbiCaKvW convert rfc822-to-8bit (ORCPT ); Thu, 31 Mar 2022 06:51:22 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51198 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232246AbiCaKvR (ORCPT ); Thu, 31 Mar 2022 06:51:17 -0400 Received: from eu-smtp-delivery-151.mimecast.com (eu-smtp-delivery-151.mimecast.com [185.58.86.151]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 919DD1BA69A for ; Thu, 31 Mar 2022 03:49:29 -0700 (PDT) Received: from AcuMS.aculab.com (156.67.243.121 [156.67.243.121]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384) id uk-mta-63-N2DKP2DGM8SWAiwiGxM7Pg-1; Thu, 31 Mar 2022 11:49:25 +0100 X-MC-Unique: N2DKP2DGM8SWAiwiGxM7Pg-1 Received: from AcuMS.Aculab.com (fd9f:af1c:a25b:0:994c:f5c2:35d6:9b65) by AcuMS.aculab.com (fd9f:af1c:a25b:0:994c:f5c2:35d6:9b65) with Microsoft SMTP Server (TLS) id 15.0.1497.32; Thu, 31 Mar 2022 11:49:24 +0100 Received: from AcuMS.Aculab.com ([fe80::994c:f5c2:35d6:9b65]) by AcuMS.aculab.com ([fe80::994c:f5c2:35d6:9b65%12]) with mapi id 15.00.1497.033; Thu, 31 Mar 2022 11:49:24 +0100 From: David Laight To: 'Dan Carpenter' CC: 'Alaa Mohamed' , "outreachy@lists.linux.dev" , "gregkh@linuxfoundation.org" , "linux-staging@lists.linux.dev" , "linux-kernel@vger.kernel.org" Subject: RE: [PATCH] staging: gdm724x: Fix Duplication of Side Effects Thread-Topic: [PATCH] staging: gdm724x: Fix Duplication of Side Effects Thread-Index: AQHYROi924sZ22xfrE+zbiso9jQv5KzZSk9w///yggCAABHMsA== Date: Thu, 31 Mar 2022 10:49:24 +0000 Message-ID: References: <20220331101849.71046-1-eng.alaamohamedsoliman.am@gmail.com> <20220331104012.GM3293@kadam> In-Reply-To: <20220331104012.GM3293@kadam> Accept-Language: en-GB, en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.202.205.107] MIME-Version: 1.0 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=C51A453 smtp.mailfrom=david.laight@aculab.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: aculab.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Dan Carpenter > Sent: 31 March 2022 11:40 > > On Thu, Mar 31, 2022 at 10:29:04AM +0000, David Laight wrote: > > From: Alaa Mohamed > > > Sent: 31 March 2022 11:19 > > > > > > Fix Duplication of Side Effects for GDM_TTY_READY(gdm) macro > > > reported by checkpatch > > > "CHECK: Macro argument reuse 'gdm' - possible side-effects?" > > > > > > Signed-off-by: Alaa Mohamed > > > --- > > > drivers/staging/gdm724x/gdm_tty.c | 4 +++- > > > 1 file changed, 3 insertions(+), 1 deletion(-) > > > > > > diff --git a/drivers/staging/gdm724x/gdm_tty.c b/drivers/staging/gdm724x/gdm_tty.c > > > index 04df6f9f5403..6f0274470e69 100644 > > > --- a/drivers/staging/gdm724x/gdm_tty.c > > > +++ b/drivers/staging/gdm724x/gdm_tty.c > > > @@ -27,7 +27,9 @@ > > > > > > #define MUX_TX_MAX_SIZE 2048 > > > > > > -#define GDM_TTY_READY(gdm) (gdm && gdm->tty_dev && gdm->port.count) > > > +#define GDM_TTY_READY(_gdm) \ > > > + ({ typeof(_gdm) (gdm) = (_gdm); \ > > > + (gdm && gdm->tty_dev && gdm->port.count); }) > > > > Did you test this? > > > > see https://godbolt.org/z/cazPrrzPv > > > > I don't understand the link. The patch should work as far as I can see. If you call GDM_TTY_READY(gdm) the first line ends up as: struct xxx *gdm = gdm; which shadows the parameter. There's probably a warning about an uninitialised variable as well. The 'gdm' and '_gdm' would need swapping over. But, as you said, just: #define GDM_TTY_READY(gdm) ((gdm) && (gdm)->tty_dev && (gdm)->port.count) is fine - I'd add the () but not worry about multiple evaluation. David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)