From patchwork Tue Aug 23 04:48:09 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sinan Kaya X-Patchwork-Id: 9294911 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 1CF1160757 for ; Tue, 23 Aug 2016 04:49:16 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 0F45B28BA2 for ; Tue, 23 Aug 2016 04:49:16 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 004D928BA8; Tue, 23 Aug 2016 04:49:15 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 7A4F028BA2 for ; Tue, 23 Aug 2016 04:49:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932687AbcHWEsc (ORCPT ); Tue, 23 Aug 2016 00:48:32 -0400 Received: from smtp.codeaurora.org ([198.145.29.96]:50115 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932638AbcHWEsb (ORCPT ); Tue, 23 Aug 2016 00:48:31 -0400 Received: by smtp.codeaurora.org (Postfix, from userid 1000) id 5FAB861CD0; Tue, 23 Aug 2016 04:48:30 +0000 (UTC) Received: from drakthul.qualcomm.com (global_nat1_iad_fw.qualcomm.com [129.46.232.65]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) (Authenticated sender: okaya@smtp.codeaurora.org) by smtp.codeaurora.org (Postfix) with ESMTPSA id D4A6161789; Tue, 23 Aug 2016 04:48:27 +0000 (UTC) From: Sinan Kaya To: dmaengine@vger.kernel.org, timur@codeaurora.org, cov@codeaurora.org, vinod.koul@intel.com, jcm@redhat.com Cc: agross@codeaurora.org, linux-arm-msm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Sinan Kaya , Dan Williams , Lars-Peter Clausen , Andy Shevchenko , Dave Jiang , linux-kernel@vger.kernel.org Subject: [PATCH V3 1/3] dmaengine: qcom_hidma: release the descriptor before the callback Date: Tue, 23 Aug 2016 00:48:09 -0400 Message-Id: <1471927691-28827-2-git-send-email-okaya@codeaurora.org> X-Mailer: git-send-email 1.8.2.1 In-Reply-To: <1471927691-28827-1-git-send-email-okaya@codeaurora.org> References: <1471927691-28827-1-git-send-email-okaya@codeaurora.org> Sender: dmaengine-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: dmaengine@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP There is a race condition between data transfer callback and descriptor free code. The callback routine may decide to clear the resources even though the descriptor has not yet been freed. Instead of calling the callback first and then releasing the memory, this code is changing the order to return the descriptor back to the free pool and then call the user provided callback. Signed-off-by: Sinan Kaya --- drivers/dma/qcom/hidma.c | 18 ++++++++++-------- 1 file changed, 10 insertions(+), 8 deletions(-) diff --git a/drivers/dma/qcom/hidma.c b/drivers/dma/qcom/hidma.c index 1197fbf..b8493ba 100644 --- a/drivers/dma/qcom/hidma.c +++ b/drivers/dma/qcom/hidma.c @@ -111,6 +111,7 @@ static void hidma_process_completed(struct hidma_chan *mchan) struct dma_async_tx_descriptor *desc; dma_cookie_t last_cookie; struct hidma_desc *mdesc; + struct hidma_desc *next; unsigned long irqflags; struct list_head list; @@ -122,8 +123,9 @@ static void hidma_process_completed(struct hidma_chan *mchan) spin_unlock_irqrestore(&mchan->lock, irqflags); /* Execute callbacks and run dependencies */ - list_for_each_entry(mdesc, &list, node) { + list_for_each_entry_safe(mdesc, next, &list, node) { enum dma_status llstat; + struct dmaengine_desc_callback cb; desc = &mdesc->desc; @@ -132,18 +134,18 @@ static void hidma_process_completed(struct hidma_chan *mchan) spin_unlock_irqrestore(&mchan->lock, irqflags); llstat = hidma_ll_status(mdma->lldev, mdesc->tre_ch); - if (llstat == DMA_COMPLETE) - dmaengine_desc_get_callback_invoke(desc, NULL); + dmaengine_desc_get_callback(desc, &cb); last_cookie = desc->cookie; dma_run_dependencies(desc); - } - /* Free descriptors */ - spin_lock_irqsave(&mchan->lock, irqflags); - list_splice_tail_init(&list, &mchan->free); - spin_unlock_irqrestore(&mchan->lock, irqflags); + spin_lock_irqsave(&mchan->lock, irqflags); + list_move(&mdesc->node, &mchan->free); + spin_unlock_irqrestore(&mchan->lock, irqflags); + if (llstat == DMA_COMPLETE) + dmaengine_desc_callback_invoke(&cb, NULL); + } } /*