On Tue, Jul 04, 2017 at 10:55:56PM +0900, Tomasz Figa wrote:
> diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
> index bf23989b5158..6ed8c8f941d8 100644
> --- a/drivers/iommu/dma-iommu.c
> +++ b/drivers/iommu/dma-iommu.c
> @@ -433,6 +433,7 @@ static struct page **__iommu_dma_alloc_pages(unsigned int
> count,
> {
> struct page **pages;
> unsigned int i = 0, array_size = count * sizeof(*pages);
> + const gfp_t high_order_gfp = __GFP_NOWARN | __GFP_NORETRY;
>
> order_mask &= (2U << MAX_ORDER) - 1;
> if (!order_mask)
> @@ -452,8 +453,6 @@ static struct page **__iommu_dma_alloc_pages(unsigned int
> count,
> if (!(gfp & (__GFP_DMA | __GFP_DMA32)))
> gfp |= __GFP_HIGHMEM;
>
> - gfp |= __GFP_NOWARN;
> -
Okay, so a warning should be there if allocation fails, independent of
what the allocation order is. So either this function prints a message
in case of allocation failure or we remove __GFP_NOWARN for all
allocation attempts.
Adding __GFP_NOWARN only makes sense when there is another fall-back in
case allocation fails anyway, which is not the case here.
> while (count) {
> struct page *page = NULL;
> unsigned int order_size;
> @@ -469,7 +468,7 @@ static struct page **__iommu_dma_alloc_pages(unsigned int
> count,
>
> order_size = 1U << order;
> page = alloc_pages((order_mask - order_size) ?
> - gfp | __GFP_NORETRY : gfp, order);
> + gfp | high_order_gfp : gfp, order);
Why does it specify __GFP_NORETRY at all? The alloc-routines in the
DMA-API don't need to be atomic.
Joerg
