Commit 177360e0 authored by Tomasz Moń's avatar Tomasz Moń Committed by Vinod Koul
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dmaengine: imx-sdma: fix cyclic buffer race condition 



Assign buffer ownership to SDMA after invoking descriptor callback to
make sure that SDMA does not write to the buffer before it is read by
the CPU.

Signed-off-by: default avatarTomasz Moń <tomasz.mon@camlingroup.com>
Link: https://lore.kernel.org/r/20220117091955.1038937-2-tomasz.mon@camlingroup.com


Signed-off-by: default avatarVinod Koul <vkoul@kernel.org>
parent 5b215c28

drivers/dma/imx-sdma.c

+3 −1
Original line number Diff line number Diff line
@@ -847,7 +847,6 @@ static void sdma_update_channel_loop(struct sdma_channel *sdmac) 
		*/



		desc->chn_real_count = bd->mode.count;

		bd->mode.status |= BD_DONE;

		bd->mode.count = desc->period_len;

		desc->buf_ptail = desc->buf_tail;

		desc->buf_tail = (desc->buf_tail + 1) % desc->num_bd;
@@ -862,6 +861,9 @@ static void sdma_update_channel_loop(struct sdma_channel *sdmac) 
		dmaengine_desc_get_callback_invoke(&desc->vd.tx, NULL);

		spin_lock(&sdmac->vc.lock);



		/* Assign buffer ownership to SDMA */

		bd->mode.status |= BD_DONE;



		if (error)

			sdmac->status = old_status;

	}