From patchwork Mon Dec 8 11:28:20 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: addy ke X-Patchwork-Id: 5455541 Return-Path: X-Original-To: patchwork-dmaengine@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 4CF5ABEEA8 for ; Mon, 8 Dec 2014 11:28:58 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 6837520166 for ; Mon, 8 Dec 2014 11:28:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6B219200FE for ; Mon, 8 Dec 2014 11:28:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755288AbaLHL2t (ORCPT ); Mon, 8 Dec 2014 06:28:49 -0500 Received: from regular2.263xmail.com ([211.157.152.3]:55752 "EHLO regular2.263xmail.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755287AbaLHL2r (ORCPT ); Mon, 8 Dec 2014 06:28:47 -0500 Received: from regular1.263xmail.com (unknown [192.168.165.230]) by regular2.263xmail.com (Postfix) with ESMTP id 90EAA1D8B6 for ; Mon, 8 Dec 2014 19:28:41 +0800 (CST) Received: from addy.ke?rock-chips.com (unknown [192.168.167.225]) by regular1.263xmail.com (Postfix) with SMTP id DC2545A87; Mon, 8 Dec 2014 19:28:34 +0800 (CST) X-263anti-spam: KSV:0; X-MAIL-GRAY: 0 X-MAIL-DELIVERY: 1 X-KSVirus-check: 0 X-ABS-CHECKED: 4 Received: from addy-vm.localdomain (localhost.localdomain [127.0.0.1]) by smtp.263.net (Postfix) with ESMTP id A846F464; Mon, 8 Dec 2014 19:28:33 +0800 (CST) X-RL-SENDER: addy.ke@rock-chips.com X-FST-TO: vinod.koul@intel.com X-SENDER-IP: 127.0.0.1 X-LOGIN-NAME: addy.ke@rock-chips.com X-UNIQUE-TAG: <8a962861e66e4d200ce9846694dca542> X-ATTACHMENT-NUM: 0 X-SENDER: kfx@rock-chips.com X-DNS-TYPE: 0 Received: from addy-vm.localdomain (unknown [127.0.0.1]) by smtp.263.net (Postfix) whith ESMTP id 8494UZJ8DT; Mon, 08 Dec 2014 19:28:36 +0800 (CST) From: Addy Ke To: vinod.koul@intel.com, dan.j.williams@intel.com, heiko@sntech.de, olof@lixom.net, dianders@chromium.org, amstan@chromium.org, sonnyrao@chromium.org Cc: dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-rockchip@lists.infradead.org, cf@rock-chips.com, xjq@rock-chips.com, huangtao@rock-chips.com, zyw@rock-chips.com, yzq@rock-chips.com, hj@rock-chips.com, kever.yang@rock-chips.com, hl@rock-chips.com, caesar.wang@rock-chips.com, zhengsq@rock-chips.com, jason.song@rock-chips.com, hhb@rock-chips.com, Addy Ke Subject: [PATCH] dmaengine: pl330: fix bug that cause start the same descs in cyclic Date: Mon, 8 Dec 2014 19:28:20 +0800 Message-Id: <1418038100-4316-1-git-send-email-addy.ke@rock-chips.com> X-Mailer: git-send-email 1.8.3.2 Sender: dmaengine-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: dmaengine@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP This bug will cause NULL pointer after commit dfac17, and cause wrong package in I2S DMA transfer before commit dfac17. Tested on RK3288-pinky2 board. Detail: I2S DMA transfer(sound/core/pcm_dmaengine.c): dmaengine_pcm_prepare_and_submit --> dmaengine_prep_dma_cyclic --> pl330_prep_dma_cyclic --> the case: 1. pl330_submit_req(desc0): thrd->req[0].desc = desc0, thrd->lstenq = 0 2. pl330_submit_req(desc1): thrd->req[1].desc = desc1, thrd->lstenq = 1 3. _start(desc0) by submit_req: thrd->req_running = 0 because: idx = 1 - thrd->lstenq = 0 4. pl330_update(desc0 OK): thrd->req[0].desc = NULL, desc0 to req_done list because: idx = active = thrd->req_running = 0 5. _start(desc1) by pl330_update: thrd->req_running = 1 because: idx = 1 - thrd->lstenq = 0, but thrd->req[0].desc == NULL, so: idx = thrd->lstenq = 1 6. pl330_submit_req(desc2): thrd->req[0].desc = desc2, thrd->lstenq = 0 7. _start(desc1) by submit_req: thrd->req_running = 1 because: idx = 1 - thrd->lstenq = 1 Note: _start started the same descs _start should start desc2 here, NOT desc1 8. pl330_update(desc1 OK): thrd->req[1].desc = NULL, desc1 to req_done list because: idx = active = thrd->req_running = 1 9. _start(desc2) by pl330_update : thrd->req_running = 0 because: idx = 1 - thrd->lstenq = 0 10.pl330_update(desc1 OK, NOT desc2): thrd->req[0].desc = NULL, desc2 to req_done list because: idx = active = thrd->req_running = 0 11.pl330_submit_req(desc3): thrd->req[0].desc = desc3, thrd->lstenq = 0 12.pl330_submit_req(desc4): thrd->req[1].desc = desc4, thrd->lstenq = 1 13._start(desc3) by submit_req: thrd->req_running = 0 because: idx = 1 - thrd->lstenq = 0 14.pl330_update(desc2 OK NOT desc3): thrd->req[0].desc = NULL desc3 to req_done list because: idx = active = thrd->req_running = 0 15._start(desc4) by pl330_update: thrd->req_running = 1 because: idx = 1 - thrd->lstenq = 0, but thrd->req[0].desc == NULL, so: idx = thrd->lstenq = 1 16.pl330_submit_req(desc5): thrd->req[0].desc = desc5, thrd->lstenq = 0 17._start(desc4) by submit_req: thrd->req_running = 1 because: idx = 1 - thrd->lstenq = 1 18.pl330_update(desc3 OK NOT desc4): thrd->req[1].desc = NULL desc4 to req_done list because: idx = active = thrd->req_running = 1 19._start(desc4) by pl330_update: thrd->req_running = 0 because: idx = 1 - thrd->lstenq = 1, but thrd->req[1].desc == NULL, so: idx = thrd->lstenq = 0 20.pl330_update(desc4 OK): thrd->req[0].desc = NULL, desc5 to req_done list because: idx = active = thrd->req_running = 0 21.pl330_update(desc4 OK): 1) before commit dfac17(set req_running -1 in pl330_update/mark_free()): because: active = -1, abort result: desc0-desc5's callback are all called, but step 10 and step 18 go wrong. 2) before commit dfac17: idx = active = thrd->req_runnig = 0 --> descdone = thrd->req[0] = NULL --> list_add_tail(&descdone->rqd, &pl330->req_done); --> got NULL pointer!!! Signed-off-by: Addy Ke --- drivers/dma/pl330.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/dma/pl330.c b/drivers/dma/pl330.c index 025b905..0773832 100644 --- a/drivers/dma/pl330.c +++ b/drivers/dma/pl330.c @@ -1044,6 +1044,10 @@ static bool _trigger(struct pl330_thread *thrd) if (!req) return true; + /* Return if req is running */ + if (idx == thrd->req_running) + return true; + desc = req->desc; ns = desc->rqcfg.nonsecure ? 1 : 0; @@ -1583,6 +1587,8 @@ static int pl330_update(struct pl330_dmac *pl330) descdone = thrd->req[active].desc; thrd->req[active].desc = NULL; + thrd->req_running = -1; + /* Get going again ASAP */ _start(thrd);