From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 51350274652 for ; Mon, 16 Jun 2025 09:53:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.176.79.56 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750067606; cv=none; b=nYz8DS9Yy2uYrv1bhvUtA3Cx6jDAn/U5ifaFl37VRFJHl5G8wvi12sCizZSRrTgIunE3bo6gbxNqM13piCDVSovBk90Lfd93Tk0f19b1SUbP4Z+4AfloDojMFIBh/ywUrLxdfjtBXbMiucVtbMAF0QOZ5ESJebFYOggm1Vix0lg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750067606; c=relaxed/simple; bh=4cv8uE6pGypsCSgH3uyNQBvUvH0nntwDkgEVp1CQBYI=; h=Date:From:To:CC:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=ZK8CArAGKWKViy5bRDgzMU8/ybwxGbH2XjdgFBL8Y00sMxq8pQcOdKGysyS5l9HXg+gt+BwsjWk9LTKDAsxcz129CrrIZ0q4hYImuDu7kUrcUxhwBgOKtF9LAxiWRgTDz7o6yM+vTKtoWVeHC3mNOWat/x2GGcRa04K9CYfkpOs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com; spf=pass smtp.mailfrom=huawei.com; arc=none smtp.client-ip=185.176.79.56 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei.com Received: from mail.maildlp.com (unknown [172.18.186.216]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4bLQHk0HX0z6L5JK; Mon, 16 Jun 2025 17:51:14 +0800 (CST) Received: from frapeml500008.china.huawei.com (unknown [7.182.85.71]) by mail.maildlp.com (Postfix) with ESMTPS id DC218140119; Mon, 16 Jun 2025 17:53:20 +0800 (CST) Received: from localhost (10.203.177.66) by frapeml500008.china.huawei.com (7.182.85.71) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.1.2507.39; Mon, 16 Jun 2025 11:53:20 +0200 Date: Mon, 16 Jun 2025 10:53:18 +0100 From: Jonathan Cameron To: Qinxin Xia CC: <21cnbao@gmail.com>, , , , , , , , , Subject: Re: [RESEND PATCH v4 1/4] dma-mapping: benchmark: Add padding to ensure uABI remained consistent Message-ID: <20250616105318.00001132@huawei.com> In-Reply-To: <20250614143454.2927363-2-xiaqinxin@huawei.com> References: <20250614143454.2927363-1-xiaqinxin@huawei.com> <20250614143454.2927363-2-xiaqinxin@huawei.com> X-Mailer: Claws Mail 4.3.0 (GTK 3.24.42; x86_64-w64-mingw32) Precedence: bulk X-Mailing-List: iommu@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-ClientProxiedBy: lhrpeml100004.china.huawei.com (7.191.162.219) To frapeml500008.china.huawei.com (7.182.85.71) On Sat, 14 Jun 2025 22:34:51 +0800 Qinxin Xia wrote: > The padding field in the structure was previously reserved to > maintain a stable interface for potential new fields, ensuring > compatibility with user-space shared data structures. > However,it was accidentally removed by tiantao in a prior commit, > which may lead to incompatibility between user space and the kernel. > > This patch reinstates the padding to restore the original structure > layout and preserve compatibility. > > Fixes: 8ddde07a3d28 ("dma-mapping: benchmark: extract a common header file for map_benchmark definition") > Cc: stable@vger.kernel.org > Acked-by: Barry Song > Signed-off-by: Qinxin Xia FWIW I checked the patch above indeed accidentally dropped the padding and the structure is copied to userspace so this fix is correct. Given it's not in a uapi header this only really affects the selftest I think this is mostly a case of there possibly being out of tree tools with a local copy of this structure definition. Reviewed-by: Jonathan Cameron