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 7458BC4332F for ; Sat, 19 Nov 2022 08:56:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233536AbiKSI43 (ORCPT ); Sat, 19 Nov 2022 03:56:29 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59018 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229470AbiKSI41 (ORCPT ); Sat, 19 Nov 2022 03:56:27 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 589B199EB2; Sat, 19 Nov 2022 00:56:26 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id DBE5E6009E; Sat, 19 Nov 2022 08:56:25 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 511E8C433C1; Sat, 19 Nov 2022 08:56:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1668848185; bh=krixhKpby3khoZS5ZrXiQOYkpJ3aUIRA96zasq5os58=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Qh0iMCLdTFFK024CYjNk1NiqC9BV6bhxUiEeq4wBDrjOZWe6BN6MNT6+Vt3pKZj61 j30ndvwKFCl/vFUvOwWE0R49wkiv6bQcCUiuRqJk6Kk5w1XnAJpF9VnlXk9f1dDH/2 Cwa3p19XwhzIC4Aaod5d7CC1jzdUQH+ovYB13y1LgKFTLga0DWfdLjoHw0qEily9He kWP7izjYKaED0Zp0nODboxV6ZGlb+dysss5sU/Xo5oXZ54XhWb9EYFF2eRdq+dNbyB 8N0VRPcpPgwS80wRZtld6nlB5XwVF3oPm2iXOdkqvRgZyrGfmDkM1np4z07pzmDQ1Y lsWqaYGDise1g== Date: Sat, 19 Nov 2022 02:56:12 -0600 From: "Gustavo A. R. Silva" To: Christophe JAILLET Cc: "Martin K. Petersen" , "James E.J. Bottomley" , GR-QLogic-Storage-Upstream@marvell.com, Nilesh Javali , linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org Subject: Re: [PATCH 1/2][next] scsi: qla2xxx: Replace one-element array with DECLARE_FLEX_ARRAY() helper Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Nov 19, 2022 at 09:44:02AM +0100, Christophe JAILLET wrote: > Le 19/11/2022 à 00:47, Gustavo A. R. Silva a écrit : > > One-element arrays as fake flex arrays are deprecated and we are moving > > towards adopting C99 flexible-array members, instead. So, replace > > one-element array declaration in struct ct_sns_gpnft_rsp, which is > > ultimately being used inside a union: > > > > drivers/scsi/qla2xxx/qla_def.h: > > 3240 struct ct_sns_gpnft_pkt { > > 3241 union { > > 3242 struct ct_sns_req req; > > 3243 struct ct_sns_gpnft_rsp rsp; > > 3244 } p; > > 3245 }; > > > > Important to mention is that doing a build before/after this patch results > > in no binary differences. > > Hi, > > even with the: > > > rspsz = sizeof(struct ct_sns_gpnft_rsp) + > > - ((vha->hw->max_fibre_devices - 1) * > > + (vha->hw->max_fibre_devices * > > sizeof(struct ct_sns_gpn_ft_data)); > > change ? Yep; that change compensates for the removal of the 1 in the declaration of entries[]. The above piece of code is a common idiom to calculate the size for an allocation when a one-element array is involved. In the original code (vha->hw->max_fibre_devices - 1) compensates for the _extra_ size of one element of type struct ct_sns_gpn_ft_data in sizeof(struct ct_sns_gpnft_rsp). -- Gustavo > > CJ > > > > > This help us make progress towards globally enabling > > -fstrict-flex-arrays=3 [1]. > > > > Link: https://github.com/KSPP/linux/issues/245 > > Link: https://github.com/KSPP/linux/issues/193 > > Link: https://gcc.gnu.org/pipermail/gcc-patches/2022-October/602902.html [1] > > Signed-off-by: Gustavo A. R. Silva > > --- > > drivers/scsi/qla2xxx/qla_def.h | 4 ++-- > > drivers/scsi/qla2xxx/qla_gs.c | 2 +- > > 2 files changed, 3 insertions(+), 3 deletions(-) > > > > diff --git a/drivers/scsi/qla2xxx/qla_def.h b/drivers/scsi/qla2xxx/qla_def.h > > index a26a373be9da..1eea977ef426 100644 > > --- a/drivers/scsi/qla2xxx/qla_def.h > > +++ b/drivers/scsi/qla2xxx/qla_def.h > > @@ -3151,12 +3151,12 @@ struct ct_sns_gpnft_rsp { > > uint8_t vendor_unique; > > }; > > /* Assume the largest number of targets for the union */ > > - struct ct_sns_gpn_ft_data { > > + DECLARE_FLEX_ARRAY(struct ct_sns_gpn_ft_data { > > u8 control_byte; > > u8 port_id[3]; > > u32 reserved; > > u8 port_name[8]; > > - } entries[1]; > > + }, entries); > > }; > > /* CT command response */ > > diff --git a/drivers/scsi/qla2xxx/qla_gs.c b/drivers/scsi/qla2xxx/qla_gs.c > > index 64ab070b8716..69d3bc795f90 100644 > > --- a/drivers/scsi/qla2xxx/qla_gs.c > > +++ b/drivers/scsi/qla2xxx/qla_gs.c > > @@ -4073,7 +4073,7 @@ int qla24xx_async_gpnft(scsi_qla_host_t *vha, u8 fc4_type, srb_t *sp) > > sp->u.iocb_cmd.u.ctarg.req_size = GPN_FT_REQ_SIZE; > > rspsz = sizeof(struct ct_sns_gpnft_rsp) + > > - ((vha->hw->max_fibre_devices - 1) * > > + (vha->hw->max_fibre_devices * > > sizeof(struct ct_sns_gpn_ft_data)); > > sp->u.iocb_cmd.u.ctarg.rsp = dma_alloc_coherent(&vha->hw->pdev->dev, >