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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id B3949C54EAA for ; Mon, 30 Jan 2023 12:44:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:Message-ID:In-Reply-To: Date:References:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=xW6GhLRrt2a/zNk5eFPSImZ/8J2rTiNw6eJHbgAMh/k=; b=wD23gK7vgGUKqD 6IVEO1r3LOlpykLmlSmujjVe8MsEtYUe4AvvilK6IjM/t+Nu5yNVTnlRkiq2ytOh5E+tJFuAdSpTL zO+EZ1xGflzqW6MOU++5ESh1bVz2h17j9gifwutirK3G+MwWJnGAsXxd+w4GsXgbZ3sujphvgpEDU nVAXkckXEDoHrtxQRhkLyozjH8aWWC5/k8ZVlg5jt2GYs1vKMpGEANVlaFuXjIvtHSNA/iUBGZgeS 5gGLF70K01YRXQlUzoKA8sy0PGzFewB5oArSCrmmMc3s/RaAyKKXuFqgxBtMnXu0AdU+i2al0PQ7m ij+PWBkXOgYL3zK7k8yg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1pMTTj-003XGR-LS; Mon, 30 Jan 2023 12:41:43 +0000 Received: from www530.your-server.de ([188.40.30.78]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1pMTTC-003XFO-H7 for linux-arm-kernel@lists.infradead.org; Mon, 30 Jan 2023 12:41:13 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=geanix.com; s=default2211; h=Content-Type:MIME-Version:Message-ID:In-Reply-To:Date: References:Subject:Cc:To:From:Sender:Reply-To:Content-Transfer-Encoding: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID; bh=WMviF2Uftt9vbt5ykM/ipziMlufm0Sdyvjcbso1WflM=; b=TnxdE7pk8vryZC8boR4sFxjH3H tdcW4rybn5CWu+T6PVRXRDtpl6Gc/pkqDRvpLmk/ambaDi2B5b64B1mtw7H3dkOPYttSMFxdSav1p kBhA85o7PHkZLj+GmSfn00oKS618xKH/RfYm7qlzlX3L3Mz6Rr7kZrSX/iZNT3NG+PcVK50SVh1sE ekjR0BHilHPBjS7TfKp8p7maTj08wik9nWxa8eXv2m2Ji4mlzMCoHn9dBq3GF9PCaLEkMKOVY+E+C i0LznAFveeE3kiAdUmlD5W+pErR8h/InInMEOXf/fm7mr5CmQzfkjc0F4H5wpDeo+gffjabcNiIbr juV/4tNg==; Received: from sslproxy01.your-server.de ([78.46.139.224]) by www530.your-server.de with esmtpsa (TLS1.3) tls TLS_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1pMTTA-00099K-7L; Mon, 30 Jan 2023 13:41:08 +0100 Received: from [80.62.117.235] (helo=localhost) by sslproxy01.your-server.de with esmtpsa (TLSv1.3:TLS_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1pMTTA-000Crk-8t; Mon, 30 Jan 2023 13:41:08 +0100 From: esben@geanix.com To: Jakub Kicinski Cc: Jonas Suhr Christensen , netdev@vger.kernel.org, davem@davemloft.net, edumazet@google.com, pabeni@redhat.com, michal.simek@xilinx.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/2] net: ll_temac: improve reset of buffer on dma mapping References: <20230126101607.88407-1-jsc@umbraculum.org> <20230126101607.88407-2-jsc@umbraculum.org> <20230127231322.08b75b36@kernel.org> Date: Mon, 30 Jan 2023 13:40:56 +0100 In-Reply-To: <20230127231322.08b75b36@kernel.org> (Jakub Kicinski's message of "Fri, 27 Jan 2023 23:13:22 -0800") Message-ID: <87edrc8aav.fsf@geanix.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.2 (gnu/linux) MIME-Version: 1.0 X-Authenticated-Sender: esben@geanix.com X-Virus-Scanned: Clear (ClamAV 0.103.7/26797/Mon Jan 30 09:24:58 2023) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230130_044110_593275_A72A042A X-CRM114-Status: GOOD ( 10.47 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Jakub Kicinski writes: > On Thu, 26 Jan 2023 11:16:07 +0100 Jonas Suhr Christensen wrote: >> Free buffer and set pointer to null on dma mapping error. > > Why? I don't see a leak. You should provide motivation in the commit > message. I don't think there is a leak. But if one of the dma_map_single() calls in temac_dma_bd_init() fails, the error handling calls into temac_dma_bd_release(), which will then call dma_unmap_single() on the address that failed to be mapped. Can we be sure that doing so is always safe? If not, this change ensures that we only unmap buffers that were succesfully mapped. /Esben _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel 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 4348AC54EED for ; Mon, 30 Jan 2023 12:41:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229769AbjA3MlS (ORCPT ); Mon, 30 Jan 2023 07:41:18 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39776 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235959AbjA3MlO (ORCPT ); Mon, 30 Jan 2023 07:41:14 -0500 X-Greylist: delayed 601 seconds by postgrey-1.37 at lindbergh.monkeyblade.net; Mon, 30 Jan 2023 04:41:10 PST Received: from www530.your-server.de (www530.your-server.de [188.40.30.78]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8DA9F1DB93; Mon, 30 Jan 2023 04:41:10 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=geanix.com; s=default2211; h=Content-Type:MIME-Version:Message-ID:In-Reply-To:Date: References:Subject:Cc:To:From:Sender:Reply-To:Content-Transfer-Encoding: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID; bh=WMviF2Uftt9vbt5ykM/ipziMlufm0Sdyvjcbso1WflM=; b=TnxdE7pk8vryZC8boR4sFxjH3H tdcW4rybn5CWu+T6PVRXRDtpl6Gc/pkqDRvpLmk/ambaDi2B5b64B1mtw7H3dkOPYttSMFxdSav1p kBhA85o7PHkZLj+GmSfn00oKS618xKH/RfYm7qlzlX3L3Mz6Rr7kZrSX/iZNT3NG+PcVK50SVh1sE ekjR0BHilHPBjS7TfKp8p7maTj08wik9nWxa8eXv2m2Ji4mlzMCoHn9dBq3GF9PCaLEkMKOVY+E+C i0LznAFveeE3kiAdUmlD5W+pErR8h/InInMEOXf/fm7mr5CmQzfkjc0F4H5wpDeo+gffjabcNiIbr juV/4tNg==; Received: from sslproxy01.your-server.de ([78.46.139.224]) by www530.your-server.de with esmtpsa (TLS1.3) tls TLS_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1pMTTA-00099K-7L; Mon, 30 Jan 2023 13:41:08 +0100 Received: from [80.62.117.235] (helo=localhost) by sslproxy01.your-server.de with esmtpsa (TLSv1.3:TLS_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1pMTTA-000Crk-8t; Mon, 30 Jan 2023 13:41:08 +0100 From: esben@geanix.com To: Jakub Kicinski Cc: Jonas Suhr Christensen , netdev@vger.kernel.org, davem@davemloft.net, edumazet@google.com, pabeni@redhat.com, michal.simek@xilinx.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/2] net: ll_temac: improve reset of buffer on dma mapping References: <20230126101607.88407-1-jsc@umbraculum.org> <20230126101607.88407-2-jsc@umbraculum.org> <20230127231322.08b75b36@kernel.org> Date: Mon, 30 Jan 2023 13:40:56 +0100 In-Reply-To: <20230127231322.08b75b36@kernel.org> (Jakub Kicinski's message of "Fri, 27 Jan 2023 23:13:22 -0800") Message-ID: <87edrc8aav.fsf@geanix.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Authenticated-Sender: esben@geanix.com X-Virus-Scanned: Clear (ClamAV 0.103.7/26797/Mon Jan 30 09:24:58 2023) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Jakub Kicinski writes: > On Thu, 26 Jan 2023 11:16:07 +0100 Jonas Suhr Christensen wrote: >> Free buffer and set pointer to null on dma mapping error. > > Why? I don't see a leak. You should provide motivation in the commit > message. I don't think there is a leak. But if one of the dma_map_single() calls in temac_dma_bd_init() fails, the error handling calls into temac_dma_bd_release(), which will then call dma_unmap_single() on the address that failed to be mapped. Can we be sure that doing so is always safe? If not, this change ensures that we only unmap buffers that were succesfully mapped. /Esben