swiotlb: Honour dma_alloc_coherent() alignment in swiotlb_alloc()

core-api/dma-api-howto.rst states the following properties of
dma_alloc_coherent():

  | The CPU virtual address and the DMA address are both guaranteed to
  | be aligned to the smallest PAGE_SIZE order which is greater than or
  | equal to the requested size.

However, swiotlb_alloc() passes zero for the 'alloc_align_mask'
parameter of swiotlb_find_slots() and so this property is not upheld.
Instead, allocations larger than a page are aligned to PAGE_SIZE,

Calculate the mask corresponding to the page order suitable for holding
the allocation and pass that to swiotlb_find_slots().

Fixes: e81e99bacc9f ("swiotlb: Support aligned swiotlb buffers")
Signed-off-by: Will Deacon <[email protected]>
Reviewed-by: Michael Kelley <[email protected]>
Reviewed-by: Petr Tesarik <[email protected]>
Tested-by: Nicolin Chen <[email protected]>
Tested-by: Michael Kelley <[email protected]>
Signed-off-by: Christoph Hellwig <[email protected]>

0 files changed, 0 insertions, 0 deletions