From 57a196a58421a4b0c45949ae7309f21829aaa77f Mon Sep 17 00:00:00 2001 From: Mike Kravetz Date: Sun, 18 Sep 2022 19:13:48 -0700 Subject: hugetlb: simplify hugetlb handling in follow_page_mask During discussions of this series [1], it was suggested that hugetlb handling code in follow_page_mask could be simplified. At the beginning of follow_page_mask, there currently is a call to follow_huge_addr which 'may' handle hugetlb pages. ia64 is the only architecture which provides a follow_huge_addr routine that does not return error. Instead, at each level of the page table a check is made for a hugetlb entry. If a hugetlb entry is found, a call to a routine associated with that entry is made. Currently, there are two checks for hugetlb entries at each page table level. The first check is of the form: if (p?d_huge()) page = follow_huge_p?d(); the second check is of the form: if (is_hugepd()) page = follow_huge_pd(). We can replace these checks, as well as the special handling routines such as follow_huge_p?d() and follow_huge_pd() with a single routine to handle hugetlb vmas. A new routine hugetlb_follow_page_mask is called for hugetlb vmas at the beginning of follow_page_mask. hugetlb_follow_page_mask will use the existing routine huge_pte_offset to walk page tables looking for hugetlb entries. huge_pte_offset can be overwritten by architectures, and already handles special cases such as hugepd entries. [1] https://lore.kernel.org/linux-mm/cover.1661240170.git.baolin.wang@linux.alibaba.com/ [mike.kravetz@oracle.com: remove vma (pmd sharing) per Peter] Link: https://lkml.kernel.org/r/20221028181108.119432-1-mike.kravetz@oracle.com [mike.kravetz@oracle.com: remove left over hugetlb_vma_unlock_read()] Link: https://lkml.kernel.org/r/20221030225825.40872-1-mike.kravetz@oracle.com Link: https://lkml.kernel.org/r/20220919021348.22151-1-mike.kravetz@oracle.com Signed-off-by: Mike Kravetz Suggested-by: David Hildenbrand Reviewed-by: David Hildenbrand Reviewed-by: Baolin Wang Tested-by: Baolin Wang Cc: Aneesh Kumar K.V Cc: Christophe Leroy Cc: Michael Ellerman Cc: Muchun Song Cc: Naoya Horiguchi Signed-off-by: Andrew Morton --- arch/ia64/mm/hugetlbpage.c | 15 --------------- 1 file changed, 15 deletions(-) (limited to 'arch/ia64/mm') diff --git a/arch/ia64/mm/hugetlbpage.c b/arch/ia64/mm/hugetlbpage.c index f993cb36c062..380d2f3966c9 100644 --- a/arch/ia64/mm/hugetlbpage.c +++ b/arch/ia64/mm/hugetlbpage.c @@ -91,21 +91,6 @@ int prepare_hugepage_range(struct file *file, return 0; } -struct page *follow_huge_addr(struct mm_struct *mm, unsigned long addr, int write) -{ - struct page *page; - pte_t *ptep; - - if (REGION_NUMBER(addr) != RGN_HPAGE) - return ERR_PTR(-EINVAL); - - ptep = huge_pte_offset(mm, addr, HPAGE_SIZE); - if (!ptep || pte_none(*ptep)) - return NULL; - page = pte_page(*ptep); - page += ((addr & ~HPAGE_MASK) >> PAGE_SHIFT); - return page; -} int pmd_huge(pmd_t pmd) { return 0; -- cgit v1.2.3