Re: [PATCH] mmc: core: Only set maximum DMA segment size if DMA is supported

[Ulf Hansson]

On Tue, 24 Sept 2024 at 23:01, Guenter Roeck <linux@xxxxxxxxxxxx> wrote:
>
> Since upstream commit 334304ac2bac ("dma-mapping: don't return errors
> from dma_set_max_seg_size") calling dma_set_max_seg_size() on a device
> not supporting DMA results in a warning traceback. This is seen when
> booting the sifive_u machine from SD. The underlying SPI controller
> (sifive,spi0 compatible) explicitly sets dma_mask to NULL.
>
> Avoid the backtrace by only calling dma_set_max_seg_size() if DMA is
> supported.
>
> Cc: Christoph Hellwig <hch@xxxxxx>
> Cc: Robin Murphy <robin.murphy@xxxxxxx>
> Cc: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
> Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>

Applied for fixes, thanks!

Kind regards
Uffe


> ---
>  drivers/mmc/core/queue.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mmc/core/queue.c b/drivers/mmc/core/queue.c
> index d0b3ca8a11f0..4d6844261912 100644
> --- a/drivers/mmc/core/queue.c
> +++ b/drivers/mmc/core/queue.c
> @@ -388,7 +388,8 @@ static struct gendisk *mmc_alloc_disk(struct mmc_queue *mq,
>
>         blk_queue_rq_timeout(mq->queue, 60 * HZ);
>
> -       dma_set_max_seg_size(mmc_dev(host), queue_max_segment_size(mq->queue));
> +       if (mmc_dev(host)->dma_parms)
> +               dma_set_max_seg_size(mmc_dev(host), queue_max_segment_size(mq->queue));
>
>         INIT_WORK(&mq->recovery_work, mmc_mq_recovery_handler);
>         INIT_WORK(&mq->complete_work, mmc_blk_mq_complete_work);
> --
> 2.45.2
>