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 gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (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 E68E2C433EF for ; Thu, 25 Nov 2021 14:08:09 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id D682D6E0CA; Thu, 25 Nov 2021 14:08:08 +0000 (UTC) Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by gabe.freedesktop.org (Postfix) with ESMTP id A1BBC6E0CA for ; Thu, 25 Nov 2021 14:08:07 +0000 (UTC) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 26E6A1FB; Thu, 25 Nov 2021 06:08:07 -0800 (PST) Received: from [10.57.56.56] (unknown [10.57.56.56]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 777393F66F; Thu, 25 Nov 2021 06:08:04 -0800 (PST) Message-ID: Date: Thu, 25 Nov 2021 14:08:00 +0000 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; rv:91.0) Gecko/20100101 Thunderbird/91.3.2 Subject: Re: [PATCH v2] dma_heap: use for_each_sgtable_sg in sg_table release flow Content-Language: en-GB To: guangming.cao@mediatek.com References: <85eb9053-0ce4-2514-06dc-58b8910dc5f7@arm.com> <20211125134951.62002-1-guangming.cao@mediatek.com> From: Robin Murphy In-Reply-To: <20211125134951.62002-1-guangming.cao@mediatek.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: wsd_upstream@mediatek.com, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, christian.koenig@amd.com, linaro-mm-sig@lists.linaro.org, lmark@codeaurora.org, benjamin.gaignard@linaro.org, matthias.bgg@gmail.com, linux-mediatek@lists.infradead.org, labbott@redhat.com, linux-arm-kernel@lists.infradead.org, linux-media@vger.kernel.org Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On 2021-11-25 13:49, guangming.cao@mediatek.com wrote: > From: Guangming > > Use (for_each_sgtable_sg) rather than (for_each_sg) to traverse > sg_table to free sg_table. > Use (for_each_sg) maybe will casuse some pages can't be freed > when send wrong nents number. It's still worth spelling out that this is fixing a bug where the current code should have been using table->orig_nents - it's just that switching to the sgtable helper is the best way to make the fix, since it almost entirely removes the possibility of making that (previously rather common) mistake. If it helps, for the change itself: Reviewed-by: Robin Murphy Thanks, Robin. > Signed-off-by: Guangming > --- > drivers/dma-buf/heaps/system_heap.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/dma-buf/heaps/system_heap.c b/drivers/dma-buf/heaps/system_heap.c > index 23a7e74ef966..8660508f3684 100644 > --- a/drivers/dma-buf/heaps/system_heap.c > +++ b/drivers/dma-buf/heaps/system_heap.c > @@ -289,7 +289,7 @@ static void system_heap_dma_buf_release(struct dma_buf *dmabuf) > int i; > > table = &buffer->sg_table; > - for_each_sg(table->sgl, sg, table->nents, i) { > + for_each_sgtable_sg(table, sg, i) { > struct page *page = sg_page(sg); > > __free_pages(page, compound_order(page)); >