From 0cd22afdcea21fa16bb5b0d3e0508ca42072d0bd Mon Sep 17 00:00:00 2001 From: John Hubbard Date: Fri, 18 Oct 2019 20:19:53 -0700 Subject: [PATCH] mm/gup: fix a misnamed "write" argument, and a related bug In several routines, the "flags" argument is incorrectly named "write". Change it to "flags". Also, in one place, the misnaming led to an actual bug: "flags & FOLL_WRITE" is required, rather than just "flags". (That problem was flagged by krobot, in v1 of this patch.) Also, change the flags argument from int, to unsigned int. You can see that this was a simple oversight, because the calling code passes "flags" to the fifth argument: gup_pgd_range(): ... if (!gup_huge_pd(__hugepd(pgd_val(pgd)), addr, PGDIR_SHIFT, next, flags, pages, nr)) ...which, until this patch, the callees referred to as "write". Also, change two lines to avoid checkpatch line length complaints, and another line to fix another oversight that checkpatch called out: missing "int" on pdshift. Link: http://lkml.kernel.org/r/20191014184639.1512873-3-jhubbard@nvidia.com Fixes: b798bec4741b ("mm/gup: change write parameter to flags in fast walk") Signed-off-by: John Hubbard Reported-by: kbuild test robot Suggested-by: Kirill A. Shutemov Suggested-by: Ira Weiny Acked-by: Kirill A. Shutemov Reviewed-by: Ira Weiny Cc: Christoph Hellwig Cc: Aneesh Kumar K.V Cc: Keith Busch Cc: Shuah Khan Cc: Christoph Hellwig Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/gup.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/mm/gup.c b/mm/gup.c index 23a9f9c9d377..8f236a335ae9 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -1973,7 +1973,8 @@ static unsigned long hugepte_addr_end(unsigned long addr, unsigned long end, } static int gup_hugepte(pte_t *ptep, unsigned long sz, unsigned long addr, - unsigned long end, int write, struct page **pages, int *nr) + unsigned long end, unsigned int flags, + struct page **pages, int *nr) { unsigned long pte_end; struct page *head, *page; @@ -1986,7 +1987,7 @@ static int gup_hugepte(pte_t *ptep, unsigned long sz, unsigned long addr, pte = READ_ONCE(*ptep); - if (!pte_access_permitted(pte, write)) + if (!pte_access_permitted(pte, flags & FOLL_WRITE)) return 0; /* hugepages are never "special" */ @@ -2023,7 +2024,7 @@ static int gup_hugepte(pte_t *ptep, unsigned long sz, unsigned long addr, } static int gup_huge_pd(hugepd_t hugepd, unsigned long addr, - unsigned int pdshift, unsigned long end, int write, + unsigned int pdshift, unsigned long end, unsigned int flags, struct page **pages, int *nr) { pte_t *ptep; @@ -2033,7 +2034,7 @@ static int gup_huge_pd(hugepd_t hugepd, unsigned long addr, ptep = hugepte_offset(hugepd, addr, pdshift); do { next = hugepte_addr_end(addr, end, sz); - if (!gup_hugepte(ptep, sz, addr, end, write, pages, nr)) + if (!gup_hugepte(ptep, sz, addr, end, flags, pages, nr)) return 0; } while (ptep++, addr = next, addr != end); @@ -2041,7 +2042,7 @@ static int gup_huge_pd(hugepd_t hugepd, unsigned long addr, } #else static inline int gup_huge_pd(hugepd_t hugepd, unsigned long addr, - unsigned pdshift, unsigned long end, int write, + unsigned int pdshift, unsigned long end, unsigned int flags, struct page **pages, int *nr) { return 0; @@ -2049,7 +2050,8 @@ static inline int gup_huge_pd(hugepd_t hugepd, unsigned long addr, #endif /* CONFIG_ARCH_HAS_HUGEPD */ static int gup_huge_pmd(pmd_t orig, pmd_t *pmdp, unsigned long addr, - unsigned long end, unsigned int flags, struct page **pages, int *nr) + unsigned long end, unsigned int flags, + struct page **pages, int *nr) { struct page *head, *page; int refs; -- GitLab