From: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx> Subject: mm: introduce page_shift() Replace PAGE_SHIFT + compound_order(page) with the new page_shift() function. Minor improvements in readability. [akpm@xxxxxxxxxxxxxxxxxxxx: fix build in tce_page_is_contained()] Link: http://lkml.kernel.org/r/201907241853.yNQTrJWd%25lkp@xxxxxxxxx Link: http://lkml.kernel.org/r/20190721104612.19120-3-willy@xxxxxxxxxxxxx Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx> Reviewed-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Reviewed-by: Ira Weiny <ira.weiny@xxxxxxxxx> Acked-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- arch/powerpc/mm/book3s64/iommu_api.c | 7 ++----- drivers/vfio/vfio_iommu_spapr_tce.c | 8 ++++---- include/linux/mm.h | 6 ++++++ 3 files changed, 12 insertions(+), 9 deletions(-) --- a/arch/powerpc/mm/book3s64/iommu_api.c~mm-introduce-page_shift +++ a/arch/powerpc/mm/book3s64/iommu_api.c @@ -129,11 +129,8 @@ static long mm_iommu_do_alloc(struct mm_ * Allow to use larger than 64k IOMMU pages. Only do that * if we are backed by hugetlb. */ - if ((mem->pageshift > PAGE_SHIFT) && PageHuge(page)) { - struct page *head = compound_head(page); - - pageshift = compound_order(head) + PAGE_SHIFT; - } + if ((mem->pageshift > PAGE_SHIFT) && PageHuge(page)) + pageshift = page_shift(compound_head(page)); mem->pageshift = min(mem->pageshift, pageshift); /* * We don't need struct page reference any more, switch --- a/drivers/vfio/vfio_iommu_spapr_tce.c~mm-introduce-page_shift +++ a/drivers/vfio/vfio_iommu_spapr_tce.c @@ -176,13 +176,13 @@ put_exit: } static bool tce_page_is_contained(struct mm_struct *mm, unsigned long hpa, - unsigned int page_shift) + unsigned int it_page_shift) { struct page *page; unsigned long size = 0; - if (mm_iommu_is_devmem(mm, hpa, page_shift, &size)) - return size == (1UL << page_shift); + if (mm_iommu_is_devmem(mm, hpa, it_page_shift, &size)) + return size == (1UL << it_page_shift); page = pfn_to_page(hpa >> PAGE_SHIFT); /* @@ -190,7 +190,7 @@ static bool tce_page_is_contained(struct * a page we just found. Otherwise the hardware can get access to * a bigger memory chunk that it should. */ - return (PAGE_SHIFT + compound_order(compound_head(page))) >= page_shift; + return page_shift(compound_head(page)) >= it_page_shift; } static inline bool tce_groups_attached(struct tce_container *container) --- a/include/linux/mm.h~mm-introduce-page_shift +++ a/include/linux/mm.h @@ -811,6 +811,12 @@ static inline unsigned long page_size(st return PAGE_SIZE << compound_order(page); } +/* Returns the number of bits needed for the number of bytes in a page */ +static inline unsigned int page_shift(struct page *page) +{ + return PAGE_SHIFT + compound_order(page); +} + void free_compound_page(struct page *page); #ifdef CONFIG_MMU _
