From: Sinan Kaya <okaya@codeaurora.org> To: dmaengine@vger.kernel.org, timur@codeaurora.org, cov@codeaurora.org Cc: linux-arm-msm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Sinan Kaya <okaya@codeaurora.org>, linux-kernel@vger.kernel.org Subject: [PATCH] dmaengine: qcom_hidma: release the descriptor before the callback Date: Wed, 13 Jul 2016 22:57:56 -0400 [thread overview] Message-ID: <1468465076-27324-1-git-send-email-okaya@codeaurora.org> (raw) 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 <okaya@codeaurora.org> --- drivers/dma/qcom/hidma.c | 26 +++++++++++++++----------- 1 file changed, 15 insertions(+), 11 deletions(-) diff --git a/drivers/dma/qcom/hidma.c b/drivers/dma/qcom/hidma.c index 41b5c6d..c41696e 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; @@ -122,28 +123,31 @@ 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) { - enum dma_status llstat; + list_for_each_entry_safe(mdesc, next, &list, node) { + dma_async_tx_callback callback; + void *param; desc = &mdesc->desc; spin_lock_irqsave(&mchan->lock, irqflags); - dma_cookie_complete(desc); + if (hidma_ll_status(mdma->lldev, mdesc->tre_ch) + == DMA_COMPLETE) + dma_cookie_complete(desc); spin_unlock_irqrestore(&mchan->lock, irqflags); - llstat = hidma_ll_status(mdma->lldev, mdesc->tre_ch); - if (desc->callback && (llstat == DMA_COMPLETE)) - desc->callback(desc->callback_param); + callback = desc->callback; + param = desc->callback_param; 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 (callback) + callback(param); + } } /* -- 1.8.2.1
WARNING: multiple messages have this Message-ID (diff)
From: okaya@codeaurora.org (Sinan Kaya) To: linux-arm-kernel@lists.infradead.org Subject: [PATCH] dmaengine: qcom_hidma: release the descriptor before the callback Date: Wed, 13 Jul 2016 22:57:56 -0400 [thread overview] Message-ID: <1468465076-27324-1-git-send-email-okaya@codeaurora.org> (raw) 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 <okaya@codeaurora.org> --- drivers/dma/qcom/hidma.c | 26 +++++++++++++++----------- 1 file changed, 15 insertions(+), 11 deletions(-) diff --git a/drivers/dma/qcom/hidma.c b/drivers/dma/qcom/hidma.c index 41b5c6d..c41696e 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; @@ -122,28 +123,31 @@ 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) { - enum dma_status llstat; + list_for_each_entry_safe(mdesc, next, &list, node) { + dma_async_tx_callback callback; + void *param; desc = &mdesc->desc; spin_lock_irqsave(&mchan->lock, irqflags); - dma_cookie_complete(desc); + if (hidma_ll_status(mdma->lldev, mdesc->tre_ch) + == DMA_COMPLETE) + dma_cookie_complete(desc); spin_unlock_irqrestore(&mchan->lock, irqflags); - llstat = hidma_ll_status(mdma->lldev, mdesc->tre_ch); - if (desc->callback && (llstat == DMA_COMPLETE)) - desc->callback(desc->callback_param); + callback = desc->callback; + param = desc->callback_param; 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 (callback) + callback(param); + } } /* -- 1.8.2.1
next reply other threads:[~2016-07-14 2:58 UTC|newest] Thread overview: 80+ messages / expand[flat|nested] mbox.gz Atom feed top 2016-07-14 2:57 Sinan Kaya [this message] 2016-07-14 2:57 ` [PATCH] dmaengine: qcom_hidma: release the descriptor before the callback Sinan Kaya 2016-07-16 1:00 ` Sinan Kaya 2016-07-16 1:00 ` Sinan Kaya 2016-07-24 6:24 ` Vinod Koul 2016-07-24 6:24 ` Vinod Koul 2016-07-25 14:19 ` Sinan Kaya 2016-07-25 14:19 ` Sinan Kaya 2016-08-04 12:55 ` Vinod Koul 2016-08-04 12:55 ` Vinod Koul 2016-08-04 12:55 ` Vinod Koul 2016-08-04 14:17 ` Sinan Kaya 2016-08-04 14:17 ` Sinan Kaya 2016-08-04 14:40 ` Russell King - ARM Linux 2016-08-04 14:40 ` Russell King - ARM Linux 2016-08-04 15:27 ` Sinan Kaya 2016-08-04 15:27 ` Sinan Kaya 2016-08-04 15:38 ` Russell King - ARM Linux 2016-08-04 15:38 ` Russell King - ARM Linux 2016-08-04 15:59 ` Lars-Peter Clausen 2016-08-04 15:59 ` Lars-Peter Clausen 2016-08-08 9:08 ` Vinod Koul 2016-08-08 9:08 ` Vinod Koul 2016-08-08 12:25 ` Lars-Peter Clausen 2016-08-08 12:25 ` Lars-Peter Clausen 2016-08-10 17:23 ` Vinod Koul 2016-08-10 17:23 ` Vinod Koul 2016-08-10 17:23 ` Vinod Koul 2016-08-04 16:08 ` Sinan Kaya 2016-08-04 16:08 ` Sinan Kaya 2016-08-04 16:15 ` Lars-Peter Clausen 2016-08-04 16:15 ` Lars-Peter Clausen 2016-08-05 6:32 ` Robert Jarzmik 2016-08-05 6:32 ` Robert Jarzmik 2016-08-05 8:34 ` Lars-Peter Clausen 2016-08-05 8:34 ` Lars-Peter Clausen 2016-08-05 8:34 ` Lars-Peter Clausen 2016-08-05 15:17 ` Sinan Kaya 2016-08-05 15:17 ` Sinan Kaya 2016-08-08 9:02 ` Vinod Koul 2016-08-08 9:02 ` Vinod Koul 2016-08-08 14:45 ` Sinan Kaya 2016-08-08 14:45 ` Sinan Kaya 2016-08-10 17:28 ` Vinod Koul 2016-08-10 17:28 ` Vinod Koul 2016-08-10 17:28 ` Vinod Koul 2016-08-10 17:31 ` Sinan Kaya 2016-08-10 17:31 ` Sinan Kaya 2016-08-10 17:31 ` Sinan Kaya 2016-08-19 2:48 ` Vinod Koul 2016-08-19 2:48 ` Vinod Koul 2016-08-19 3:26 ` Sinan Kaya 2016-08-19 3:26 ` Sinan Kaya 2016-08-19 3:26 ` Sinan Kaya 2016-08-19 3:42 ` Vinod Koul 2016-08-19 3:42 ` Vinod Koul 2016-08-19 3:48 ` Sinan Kaya 2016-08-19 3:48 ` Sinan Kaya 2016-08-19 5:52 ` Vinod Koul 2016-08-19 5:52 ` Vinod Koul 2016-08-19 11:13 ` okaya 2016-08-19 11:13 ` okaya at codeaurora.org 2016-08-19 11:13 ` okaya 2016-08-19 17:02 ` Vinod Koul 2016-08-19 17:02 ` Vinod Koul 2016-08-19 17:02 ` Vinod Koul 2016-08-19 17:21 ` Sinan Kaya 2016-08-19 17:21 ` Sinan Kaya 2016-08-19 17:21 ` Sinan Kaya 2016-08-22 6:08 ` Vinod Koul 2016-08-22 6:08 ` Vinod Koul 2016-08-22 6:08 ` Vinod Koul 2016-08-22 13:27 ` Sinan Kaya 2016-08-22 13:27 ` Sinan Kaya 2016-08-22 17:00 ` Vinod Koul 2016-08-22 17:00 ` Vinod Koul 2016-08-08 8:51 ` Vinod Koul 2016-08-08 8:51 ` Vinod Koul 2016-08-08 12:10 ` okaya 2016-08-08 12:10 ` okaya at codeaurora.org
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