Re: [PATCH] swiotlb: Fix type of max_slot

[Konrad Rzeszutek Wilk]

On 3/2/21 12:21 PM, Kunihiko Hayashi wrote:
> After the refactoring phase, the type of max_slot has changed from unsigned
> long to unsigned int. The return type of the function get_max_slots() and
> the 4th argument type of iommu_is_span_boundary() are different from the
> type of max_slot. Finally, asserts BUG_ON in iommu_is_span_boundary().
>
> Cc: Christoph Hellwig <hch@xxxxxx>
> Fixes: 567d877f9a7d ("swiotlb: refactor swiotlb_tbl_map_single")
> Signed-off-by: Kunihiko Hayashi <hayashi.kunihiko@xxxxxxxxxxxxx>

I think this is all good. Looking at Linus's master I see:


537         unsigned long max_slots = get_max_slots(boundary_mask);

?

> ---
>   kernel/dma/swiotlb.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
> index 369e4c3..c10e855 100644
> --- a/kernel/dma/swiotlb.c
> +++ b/kernel/dma/swiotlb.c
> @@ -534,7 +534,7 @@ static int find_slots(struct device *dev, phys_addr_t orig_addr,
>   	unsigned long boundary_mask = dma_get_seg_boundary(dev);
>   	dma_addr_t tbl_dma_addr =
>   		phys_to_dma_unencrypted(dev, io_tlb_start) & boundary_mask;
> -	unsigned int max_slots = get_max_slots(boundary_mask);
> +	unsigned long max_slots = get_max_slots(boundary_mask);
>   	unsigned int iotlb_align_mask =
>   		dma_get_min_align_mask(dev) & ~(IO_TLB_SIZE - 1);
>   	unsigned int nslots = nr_slots(alloc_size), stride;