From: David Woodhouse Date: Thu, 2 Jul 2009 10:21:16 +0000 (+0100) Subject: intel-iommu: Introduce first_pte_in_page() to simplify PTE-setting loops X-Git-Tag: Ubuntu-5.2.0-15.16~28768^2~1 X-Git-Url: https://git.proxmox.com/?a=commitdiff_plain;h=75e6bf9638992dfc0fec9c3ca10444c8e0d6a638;p=mirror_ubuntu-eoan-kernel.git 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: David Woodhouse --- diff --git a/drivers/pci/intel-iommu.c b/drivers/pci/intel-iommu.c index 2c1b2babfdc5..dcf0295a9b60 100644 --- a/drivers/pci/intel-iommu.c +++ b/drivers/pci/intel-iommu.c @@ -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;