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| author |   Dan Williams <dan.j.williams@intel.com> | 2017-03-09 16:16:45 -0800 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@linux-foundation.org> | 2017-03-09 17:01:09 -0800 |
| commit | b2e593e271b0760ebc8999e5f9dd068ae2b9d30a (patch) | |
| tree | cafd706b335db08092cea4ed58b6510321910906 /arch/x86 | |
| parent | x86, mm: fix gup_pte_range() vs DAX mappings (diff) | |
| download | linux-dev-b2e593e271b0760ebc8999e5f9dd068ae2b9d30a.tar.xz linux-dev-b2e593e271b0760ebc8999e5f9dd068ae2b9d30a.zip | |
x86, mm: unify exit paths in gup_pte_range()
All exit paths from gup_pte_range() require pte_unmap() of the original
pte page before returning. Refactor the code to have a single exit
point to do the unmap.
This mirrors the flow of the generic gup_pte_range() in mm/gup.c.
Link: http://lkml.kernel.org/r/148804251828.36605.14910389618497006945.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/mm/gup.c | 39 |
1 files changed, 20 insertions, 19 deletions
diff --git a/arch/x86/mm/gup.c b/arch/x86/mm/gup.c index 9d32ee608807..1f3b6ef105cd 100644 --- a/arch/x86/mm/gup.c +++ b/arch/x86/mm/gup.c @@ -106,36 +106,35 @@ static noinline int gup_pte_range(pmd_t pmd, unsigned long addr, unsigned long end, int write, struct page **pages, int *nr) { struct dev_pagemap *pgmap = NULL; - int nr_start = *nr; - pte_t *ptep; + int nr_start = *nr, ret = 0; + pte_t *ptep, *ptem; - ptep = pte_offset_map(&pmd, addr); + /* + * Keep the original mapped PTE value (ptem) around since we + * might increment ptep off the end of the page when finishing + * our loop iteration. + */ + ptem = ptep = pte_offset_map(&pmd, addr); do { pte_t pte = gup_get_pte(ptep); struct page *page; /* Similar to the PMD case, NUMA hinting must take slow path */ - if (pte_protnone(pte)) { - pte_unmap(ptep); - return 0; - } + if (pte_protnone(pte)) + break; - if (!pte_allows_gup(pte_val(pte), write)) { - pte_unmap(ptep); - return 0; - } + if (!pte_allows_gup(pte_val(pte), write)) + break; if (pte_devmap(pte)) { pgmap = get_dev_pagemap(pte_pfn(pte), pgmap); if (unlikely(!pgmap)) { undo_dev_pagemap(nr, nr_start, pages); - pte_unmap(ptep); - return 0; + break; } - } else if (pte_special(pte)) { - pte_unmap(ptep); - return 0; - } + } else if (pte_special(pte)) + break; + VM_BUG_ON(!pfn_valid(pte_pfn(pte))); page = pte_page(pte); get_page(page); @@ -145,9 +144,11 @@ static noinline int gup_pte_range(pmd_t pmd, unsigned long addr, (*nr)++; } while (ptep++, addr += PAGE_SIZE, addr != end); - pte_unmap(ptep - 1); + if (addr == end) + ret = 1; + pte_unmap(ptem); - return 1; + return ret; } static inline void get_head_page_multiple(struct page *page, int nr) |