On Thu, Oct 18, 2018 at 09:18:15PM +0800, Ming Lei wrote:
> This patch converts .dma_alignment into stacked limit, so the stack
> driver may get updated with underlying dma alignment, and allocate
> IO buffer as queue DMA aligned.
>
> Cc: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
> Cc: Dave Chinner <dchinner@xxxxxxxxxx>
> Cc: Linux FS Devel <linux-fsdevel@xxxxxxxxxxxxxxx>
> Cc: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
> Cc: xfs@xxxxxxxxxxxxxxx
> Cc: Dave Chinner <dchinner@xxxxxxxxxx>
> Cc: Christoph Hellwig <hch@xxxxxx>
> Cc: Bart Van Assche <bvanassche@xxxxxxx>
> Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
> Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx>
> ---
> block/blk-settings.c | 89 +++++++++++++++++++++++++++++-----------------------
> 1 file changed, 50 insertions(+), 39 deletions(-)
>
> diff --git a/block/blk-settings.c b/block/blk-settings.c
> index cf9cd241dc16..aef4510a99b6 100644
> --- a/block/blk-settings.c
> +++ b/block/blk-settings.c
> @@ -525,6 +525,54 @@ void blk_queue_stack_limits(struct request_queue *t, struct request_queue *b)
> EXPORT_SYMBOL(blk_queue_stack_limits);
>
> /**
> + * blk_queue_dma_alignment - set dma length and memory alignment
> + * @q: the request queue for the device
> + * @mask: alignment mask
> + *
> + * description:
> + * set required memory and length alignment for direct dma transactions.
> + * this is used when building direct io requests for the queue.
> + *
> + **/
> +void blk_queue_dma_alignment(struct request_queue *q, int mask)
> +{
> + q->limits.dma_alignment = mask;
> +}
> +EXPORT_SYMBOL(blk_queue_dma_alignment);
Any good reason not to keep these functions where they were before?
> +
> +static int __blk_queue_update_dma_alignment(struct queue_limits *t, int mask)
> +{
> + BUG_ON(mask >= PAGE_SIZE);
> +
> + if (mask > t->dma_alignment)
> + return mask;
> + else
> + return t->dma_alignment;
I think this function could just be replaced with a:
max(t->dma_alignment, mask);
