Commit 06988949 authored by Tudor Ambarus's avatar Tudor Ambarus Committed by Vinod Koul
Browse files

dmaengine: at_hdmac: Fix concurrency over descriptor 



The descriptor was added to the free_list before calling the callback,
which could result in reissuing of the same descriptor and calling of a
single callback for both. Move the decriptor to the free list after the
callback is invoked.

Fixes: dc78baa2 ("dmaengine: at_hdmac: new driver for the Atmel AHB DMA Controller")
Reported-by: default avatarPeter Rosin <peda@axentia.se>
Signed-off-by: default avatarTudor Ambarus <tudor.ambarus@microchip.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/lkml/13c6c9a2-6db5-c3bf-349b-4c127ad3496a@axentia.se/


Acked-by: default avatarNicolas Ferre <nicolas.ferre@microchip.com>
Link: https://lore.kernel.org/r/20221025090306.297886-1-tudor.ambarus@microchip.com
Link: https://lore.kernel.org/r/20221025090306.297886-9-tudor.ambarus@microchip.com


Signed-off-by: default avatarVinod Koul <vkoul@kernel.org>
parent c6babed8

drivers/dma/at_hdmac.c

+9 −5
Original line number Diff line number Diff line
@@ -469,11 +469,8 @@ atc_chain_complete(struct at_dma_chan *atchan, struct at_desc *desc) 
		desc->memset_buffer = false;

	}



	/* move children to free_list */

	list_splice_init(&desc->tx_list, &atchan->free_list);

	/* move myself to free_list */

	list_move(&desc->desc_node, &atchan->free_list);



	/* Remove transfer node from the active list. */

	list_del_init(&desc->desc_node);

	spin_unlock_irqrestore(&atchan->lock, flags);



	dma_descriptor_unmap(txd);
@@ -483,6 +480,13 @@ atc_chain_complete(struct at_dma_chan *atchan, struct at_desc *desc) 
		dmaengine_desc_get_callback_invoke(txd, NULL);



	dma_run_dependencies(txd);



	spin_lock_irqsave(&atchan->lock, flags);

	/* move children to free_list */

	list_splice_init(&desc->tx_list, &atchan->free_list);

	/* add myself to free_list */

	list_add(&desc->desc_node, &atchan->free_list);

	spin_unlock_irqrestore(&atchan->lock, flags);

}



/**