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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>
This commit is contained in:
Dan Williams 2017-03-09 16:16:45 -08:00 committed by Linus Torvalds
parent ef947b2529
commit b2e593e271
1 changed files with 20 additions and 19 deletions
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39
arch/x86/mm/gup.c
View File

@ -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)