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 X-Spam-Level: X-Spam-Status: No, score=-8.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E2C06C33CB2 for ; Wed, 29 Jan 2020 11:01:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B38DB2071E for ; Wed, 29 Jan 2020 11:01:28 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=nvidia.com header.i=@nvidia.com header.b="e6wu75Gh" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726116AbgA2LB2 (ORCPT ); Wed, 29 Jan 2020 06:01:28 -0500 Received: from hqnvemgate24.nvidia.com ([216.228.121.143]:5027 "EHLO hqnvemgate24.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726067AbgA2LB2 (ORCPT ); Wed, 29 Jan 2020 06:01:28 -0500 Received: from hqpgpgate101.nvidia.com (Not Verified[216.228.121.13]) by hqnvemgate24.nvidia.com (using TLS: TLSv1.2, DES-CBC3-SHA) id ; Wed, 29 Jan 2020 03:00:36 -0800 Received: from hqmail.nvidia.com ([172.20.161.6]) by hqpgpgate101.nvidia.com (PGP Universal service); Wed, 29 Jan 2020 03:01:27 -0800 X-PGP-Universal: processed; by hqpgpgate101.nvidia.com on Wed, 29 Jan 2020 03:01:27 -0800 Received: from [10.21.133.51] (172.20.13.39) by HQMAIL107.nvidia.com (172.20.187.13) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Wed, 29 Jan 2020 11:01:25 +0000 Subject: Re: [PATCH v5 05/14] dmaengine: tegra-apb: Prevent race conditions of tasklet vs free list To: Dmitry Osipenko , Laxman Dewangan , Vinod Koul , Dan Williams , Thierry Reding , =?UTF-8?B?TWljaGHFgiBNaXJvc8WCYXc=?= CC: , , References: <20200123230325.3037-1-digetx@gmail.com> <20200123230325.3037-6-digetx@gmail.com> From: Jon Hunter Message-ID: Date: Wed, 29 Jan 2020 11:01:23 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.4.1 MIME-Version: 1.0 In-Reply-To: <20200123230325.3037-6-digetx@gmail.com> X-Originating-IP: [172.20.13.39] X-ClientProxiedBy: HQMAIL107.nvidia.com (172.20.187.13) To HQMAIL107.nvidia.com (172.20.187.13) Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1580295636; bh=IfKZdGdepzhRKX00fBnJencRopRc26wyCay/acOGi4Q=; h=X-PGP-Universal:Subject:To:CC:References:From:Message-ID:Date: User-Agent:MIME-Version:In-Reply-To:X-Originating-IP: X-ClientProxiedBy:Content-Type:Content-Language: Content-Transfer-Encoding; b=e6wu75GhRTBJDe5OiSXPn3K8HO9yRcymv9AH+Q0x2tE12qNP4EEqItT13VtfkB2EC jmuULTNVE67Y+T1MtFg0IcnUNveYUmVJj3TqfNFXjzttlbg5pXS9QWAkq7/Kt8GTVZ K3VAxpxg/+4xvBx/gfNI/qDnBJFICIWuu7RAZL/DcnLhkeuTBQd2Zxtu047/ieBoVE lJs30ynrLNNj62/qvQrklbUyc0il+aRpq8aU/xjFemaVcrUohRRwmaImt64XEKS8n5 gFoUaaAtZNY5wPN26RK/s64LpHjxB4OLWwihlr6pGpvLnACDHzRX1oIfXm0Qb5zypd L4NWI+5Rmr82g== Sender: dmaengine-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: dmaengine@vger.kernel.org On 23/01/2020 23:03, Dmitry Osipenko wrote: > The interrupt handler puts a half-completed DMA descriptor on a free list > and then schedules tasklet to process bottom half of the descriptor that > executes client's callback, this creates possibility to pick up the busy > descriptor from the free list. Thus let's disallow descriptor's re-use > until it is fully processed. > > Acked-by: Jon Hunter > Signed-off-by: Dmitry Osipenko > --- > drivers/dma/tegra20-apb-dma.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c > index 1b8a11804962..aafad50d075e 100644 > --- a/drivers/dma/tegra20-apb-dma.c > +++ b/drivers/dma/tegra20-apb-dma.c > @@ -281,7 +281,7 @@ static struct tegra_dma_desc *tegra_dma_desc_get( > > /* Do not allocate if desc are waiting for ack */ > list_for_each_entry(dma_desc, &tdc->free_dma_desc, node) { > - if (async_tx_test_ack(&dma_desc->txd)) { > + if (async_tx_test_ack(&dma_desc->txd) && !dma_desc->cb_count) { > list_del(&dma_desc->node); > spin_unlock_irqrestore(&tdc->lock, flags); > dma_desc->txd.flags = 0; > I think we should mark this for stable as well. I would make this the 2nd patch in the series as it is related to #1. Jon -- nvpublic