[PATCH] iommu/amd: Pass gfp flags to iommu_map_page() in amd_iommu_map()
Robin Murphy
robin.murphy at arm.com
Fri Oct 18 09:50:34 UTC 2019
On 2019-10-18 10:27 am, Dan Carpenter wrote:
> Did you get a chance to look at iommu_dma_alloc_remap() as well?
>
> drivers/iommu/dma-iommu.c
> 584 static void *iommu_dma_alloc_remap(struct device *dev, size_t size,
> 585 dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs)
> ^^^^^^^^^
> 586 {
> 587 struct iommu_domain *domain = iommu_get_dma_domain(dev);
> 588 struct iommu_dma_cookie *cookie = domain->iova_cookie;
> 589 struct iova_domain *iovad = &cookie->iovad;
> 590 bool coherent = dev_is_dma_coherent(dev);
> 591 int ioprot = dma_info_to_prot(DMA_BIDIRECTIONAL, coherent, attrs);
> 592 pgprot_t prot = dma_pgprot(dev, PAGE_KERNEL, attrs);
> 593 unsigned int count, min_size, alloc_sizes = domain->pgsize_bitmap;
> 594 struct page **pages;
> 595 struct sg_table sgt;
> 596 dma_addr_t iova;
> 597 void *vaddr;
> 598
> 599 *dma_handle = DMA_MAPPING_ERROR;
> 600
> 601 if (unlikely(iommu_dma_deferred_attach(dev, domain)))
> 602 return NULL;
> 603
> 604 min_size = alloc_sizes & -alloc_sizes;
> 605 if (min_size < PAGE_SIZE) {
> 606 min_size = PAGE_SIZE;
> 607 alloc_sizes |= PAGE_SIZE;
> 608 } else {
> 609 size = ALIGN(size, min_size);
> 610 }
> 611 if (attrs & DMA_ATTR_ALLOC_SINGLE_PAGES)
> 612 alloc_sizes = min_size;
> 613
> 614 count = PAGE_ALIGN(size) >> PAGE_SHIFT;
> 615 pages = __iommu_dma_alloc_pages(dev, count, alloc_sizes >> PAGE_SHIFT,
> 616 gfp);
> 617 if (!pages)
> 618 return NULL;
> 619
> 620 size = iova_align(iovad, size);
> 621 iova = iommu_dma_alloc_iova(domain, size, dev->coherent_dma_mask, dev);
> 622 if (!iova)
> 623 goto out_free_pages;
> 624
> 625 if (sg_alloc_table_from_pages(&sgt, pages, count, 0, size, GFP_KERNEL))
> ^^^^^^^^^^
> gfp here instead of GFP_KERNEL?
This is, from what I remember, intentional - it's a temporary allocation
which doesn't need to have the same restrictions as the actual buffer
being allocated (e.g. GFP_DMA32 etc.). We don't need to worry about
GFP_ATOMIC since the whole thing is only ever called in sleeping contexts.
Robin.
>
> 626 goto out_free_iova;
> 627
> 628 if (!(ioprot & IOMMU_CACHE)) {
>
> regards,
> dan carpenter
>
> _______________________________________________
> iommu mailing list
> iommu at lists.linux-foundation.org
> https://lists.linuxfoundation.org/mailman/listinfo/iommu
>
More information about the iommu
mailing list