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Commit 8a31f8b5 authored by Sinan Kaya's avatar Sinan Kaya Committed by Vinod Koul
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dmaengine: qcom_hidma: release the descriptor before the callback 



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: default avatarSinan Kaya <okaya@codeaurora.org>
Signed-off-by: default avatarVinod Koul <vinod.koul@intel.com>
parent 73fc45e3

drivers/dma/qcom/hidma.c

+10 −8
Original line number Diff line number Diff line
@@ -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);

		list_move(&mdesc->node, &mchan->free);

		spin_unlock_irqrestore(&mchan->lock, irqflags);



		if (llstat == DMA_COMPLETE)

			dmaengine_desc_callback_invoke(&cb, NULL);

	}

}



/*