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-rw-r--r--arch/x86/mm/gup.c37
1 files changed, 21 insertions, 16 deletions
diff --git a/arch/x86/mm/gup.c b/arch/x86/mm/gup.c
index 99c7805a9693..1f3b6ef105cd 100644
--- a/arch/x86/mm/gup.c
+++ b/arch/x86/mm/gup.c
@@ -106,32 +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))
+ 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_allows_gup(pte_val(pte), write) ||
- 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);
@@ -141,9 +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)