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Commit 75e6bf96 authored by David Woodhouse's avatar David Woodhouse
Browse files

intel-iommu: Introduce first_pte_in_page() to simplify PTE-setting loops 



On Wed, 2009-07-01 at 16:59 -0700, Linus Torvalds wrote:
> I also _really_ hate how you do
>
>         (unsigned long)pte >> VTD_PAGE_SHIFT ==
>         (unsigned long)first_pte >> VTD_PAGE_SHIFT

Kill this, in favour of just looking to see if the incremented pte
pointer has 'wrapped' onto the next page. Which means we have to check
it _after_ incrementing it, not before.

Signed-off-by: default avatarDavid Woodhouse <David.Woodhouse@intel.com>
parent 7766a3fb

drivers/pci/intel-iommu.c

+13 −11
Original line number Diff line number Diff line
@@ -240,6 +240,11 @@ static inline bool dma_pte_present(struct dma_pte *pte) 
	return (pte->val & 3) != 0;

}



static inline int first_pte_in_page(struct dma_pte *pte)

{

	return !((unsigned long)pte & ~VTD_PAGE_MASK);

}



/*

 * This domain is a statically identity mapping domain.

 *	1. This domain creats a static 1:1 mapping to all usable memory.
@@ -780,13 +785,12 @@ static void dma_pte_clear_range(struct dmar_domain *domain, 
			start_pfn = align_to_level(start_pfn + 1, 2);

			continue;

		}

		while (start_pfn <= last_pfn &&

		       (unsigned long)pte >> VTD_PAGE_SHIFT ==

		       (unsigned long)first_pte >> VTD_PAGE_SHIFT) {

		do { 

			dma_clear_pte(pte);

			start_pfn++;

			pte++;

		}

		} while (start_pfn <= last_pfn && !first_pte_in_page(pte));



		domain_flush_cache(domain, first_pte,

				   (void *)pte - (void *)first_pte);

	}
@@ -821,14 +825,14 @@ static void dma_pte_free_pagetable(struct dmar_domain *domain, 
				tmp = align_to_level(tmp + 1, level + 1);

				continue;

			}

			while (tmp + level_size(level) - 1 <= last_pfn &&

			       (unsigned long)pte >> VTD_PAGE_SHIFT ==

			       (unsigned long)first_pte >> VTD_PAGE_SHIFT) {

			do {

				free_pgtable_page(phys_to_virt(dma_pte_addr(pte)));

				dma_clear_pte(pte);

				pte++;

				tmp += level_size(level);

			}

			} while (!first_pte_in_page(pte) &&

				 tmp + level_size(level) - 1 <= last_pfn);



			domain_flush_cache(domain, first_pte,

					   (void *)pte - (void *)first_pte);
@@ -1694,9 +1698,7 @@ static int __domain_mapping(struct dmar_domain *domain, unsigned long iov_pfn, 
			WARN_ON(1);

		}

		pte++;

		if (!nr_pages ||

		    (unsigned long)pte >> VTD_PAGE_SHIFT !=

		    (unsigned long)first_pte >> VTD_PAGE_SHIFT) {

		if (!nr_pages || first_pte_in_page(pte)) {

			domain_flush_cache(domain, first_pte,

					   (void *)pte - (void *)first_pte);

			pte = NULL;