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authorDan Williams <dan.j.williams@intel.com>2017-03-10 03:16:45 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2017-03-10 04:01:09 +0300
commitb2e593e271b0760ebc8999e5f9dd068ae2b9d30a (patch)
treecafd706b335db08092cea4ed58b6510321910906 /arch
parentef947b2529f918d9606533eb9c32b187ed6a5ede (diff)
downloadlinux-b2e593e271b0760ebc8999e5f9dd068ae2b9d30a.tar.xz
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')
-rw-r--r--arch/x86/mm/gup.c39
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)