Re: [PATCH] mtd: rawnand: lpc32xx_slc: fail DMA transfer on completion timeout

[Vladimir Zapolskiy]

On 6/24/26 17:41, Pengpeng Hou wrote:
> lpc32xx_xmit_dma() waits for the DMA completion callback but ignores
> wait_for_completion_timeout(). A timed out DMA transfer is therefore
> unmapped and reported as successful to the NAND read/write path.
>
> Return -ETIMEDOUT when the completion wait expires. Terminate the DMA
> channel before unmapping the scatterlist so the timed out transfer cannot
> continue to access the buffer after the error is returned.
>
> Signed-off-by: Pengpeng Hou <pengpeng@xxxxxxxxxxx>
> ---
>   drivers/mtd/nand/raw/lpc32xx_slc.c | 12 ++++++++++--
>   1 file changed, 10 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/mtd/nand/raw/lpc32xx_slc.c b/drivers/mtd/nand/raw/lpc32xx_slc.c
> index 3ca30e7dc..10c808020 100644
> --- a/drivers/mtd/nand/raw/lpc32xx_slc.c
> +++ b/drivers/mtd/nand/raw/lpc32xx_slc.c
> @@ -430,6 +430,7 @@ static int lpc32xx_xmit_dma(struct mtd_info *mtd, dma_addr_t dma,
>   	struct dma_async_tx_descriptor *desc;
>   	int flags = DMA_CTRL_ACK | DMA_PREP_INTERRUPT;
>   	int res;
> +	unsigned long time_left;
>   
>   	host->dma_slave_config.direction = dir;
>   	host->dma_slave_config.src_addr = dma;
> @@ -467,12 +468,19 @@ static int lpc32xx_xmit_dma(struct mtd_info *mtd, dma_addr_t dma,
>   	dmaengine_submit(desc);
>   	dma_async_issue_pending(host->dma_chan);
>   
> -	wait_for_completion_timeout(&host->comp, msecs_to_jiffies(1000));
> +	time_left = wait_for_completion_timeout(&host->comp,
> +						msecs_to_jiffies(1000));
> +	if (!time_left) {
> +		dmaengine_terminate_sync(host->dma_chan);
> +		res = -ETIMEDOUT;
> +	} else {
> +		res = 0;
> +	}
>   
>   	dma_unmap_sg(host->dma_chan->device->dev, &host->sgl, 1,
>   		     DMA_BIDIRECTIONAL);
>   
> -	return 0;
> +	return res;
>   out1:
>   	dma_unmap_sg(host->dma_chan->device->dev, &host->sgl, 1,
>   		     DMA_BIDIRECTIONAL);

Thank you for the change.

Reviewed-by: Vladimir Zapolskiy <vz@xxxxxxxxxx>

--
Best wishes,
Vladimir