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From: Johannes Weiner on 23 Mar 2010 10:40
Instead of passing a start address and a number of pages into the
helper functions, convert them to use a start and an end address.

Signed-off-by: Johannes Weiner <hannes(a)cmpxchg.org>
---
mm/mincore.c | 57 +++++++++++++++++++++++++++------------------------------
1 files changed, 27 insertions(+), 30 deletions(-)

diff --git a/mm/mincore.c b/mm/mincore.c
index ba80bb8..eb50daa 100644
--- a/mm/mincore.c
+++ b/mm/mincore.c
@@ -20,14 +20,12 @@
#include <asm/pgtable.h>

static void mincore_hugetlb_page_range(struct vm_area_struct *vma,
- unsigned long addr, unsigned long nr,
+ unsigned long addr, unsigned long end,
unsigned char *vec)
{
#ifdef CONFIG_HUGETLB_PAGE
struct hstate *h;
- int i;

- i = 0;
h = hstate_vma(vma);
while (1) {
unsigned char present;
@@ -40,10 +38,10 @@ static void mincore_hugetlb_page_range(struct vm_area_struct *vma,
addr & huge_page_mask(h));
present = ptep && !huge_pte_none(huge_ptep_get(ptep));
while (1) {
- vec[i++] = present;
+ *vec = present;
+ vec++;
addr += PAGE_SIZE;
- /* reach buffer limit */
- if (i == nr)
+ if (addr == end)
return;
/* check hugepage border */
if (!(addr & ~huge_page_mask(h)))
@@ -86,9 +84,10 @@ static unsigned char mincore_page(struct address_space *mapping, pgoff_t pgoff)
}

static void mincore_unmapped_range(struct vm_area_struct *vma,
- unsigned long addr, unsigned long nr,
+ unsigned long addr, unsigned long end,
unsigned char *vec)
{
+ unsigned long nr = (end - addr) >> PAGE_SHIFT;
int i;

if (vma->vm_file) {
@@ -104,42 +103,44 @@ static void mincore_unmapped_range(struct vm_area_struct *vma,
}

static void mincore_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
- unsigned long addr, unsigned long nr,
+ unsigned long addr, unsigned long end,
unsigned char *vec)
{
+ unsigned long next;
spinlock_t *ptl;
pte_t *ptep;
- int i;

ptep = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
- for (i = 0; i < nr; i++, ptep++, addr += PAGE_SIZE) {
+ do {
pte_t pte = *ptep;
pgoff_t pgoff;

+ next = addr + PAGE_SIZE;
if (pte_none(pte))
- mincore_unmapped_range(vma, addr, 1, vec);
+ mincore_unmapped_range(vma, addr, next, vec);
else if (pte_present(pte))
- vec[i] = 1;
+ *vec = 1;
else if (pte_file(pte)) {
pgoff = pte_to_pgoff(pte);
- vec[i] = mincore_page(vma->vm_file->f_mapping, pgoff);
+ *vec = mincore_page(vma->vm_file->f_mapping, pgoff);
} else { /* pte is a swap entry */
swp_entry_t entry = pte_to_swp_entry(pte);

if (is_migration_entry(entry)) {
/* migration entries are always uptodate */
- vec[i] = 1;
+ *vec = 1;
} else {
#ifdef CONFIG_SWAP
pgoff = entry.val;
- vec[i] = mincore_page(&swapper_space, pgoff);
+ *vec = mincore_page(&swapper_space, pgoff);
#else
WARN_ON(1);
- vec[i] = 1;
+ *vec = 1;
#endif
}
}
- }
+ vec++;
+ } while (ptep++, addr = next, addr != end);
pte_unmap_unlock(ptep - 1, ptl);
}

@@ -153,25 +154,21 @@ static long do_mincore(unsigned long addr, unsigned long pages, unsigned char *v
pgd_t *pgd;
pud_t *pud;
pmd_t *pmd;
- unsigned long nr;
struct vm_area_struct *vma;
+ unsigned long end;

vma = find_vma(current->mm, addr);
if (!vma || addr < vma->vm_start)
return -ENOMEM;

- nr = min(pages, (vma->vm_end - addr) >> PAGE_SHIFT);
+ end = min(vma->vm_end, addr + (pages << PAGE_SHIFT));

if (is_vm_hugetlb_page(vma)) {
- mincore_hugetlb_page_range(vma, addr, nr, vec);
- return nr;
+ mincore_hugetlb_page_range(vma, addr, end, vec);
+ return (end - addr) >> PAGE_SHIFT;
}

- /*
- * Calculate how many pages there are left in the last level of the
- * PTE array for our address.
- */
- nr = min(nr, PTRS_PER_PTE - ((addr >> PAGE_SHIFT) & (PTRS_PER_PTE-1)));
+ end = pmd_addr_end(addr, end);

pgd = pgd_offset(vma->vm_mm, addr);
if (pgd_none_or_clear_bad(pgd))
@@ -184,12 +181,12 @@ static long do_mincore(unsigned long addr, unsigned long pages, unsigned char *v
if (pmd_none_or_clear_bad(pmd))
goto none_mapped;

- mincore_pte_range(vma, pmd, addr, nr, vec);
- return nr;
+ mincore_pte_range(vma, pmd, addr, end, vec);
+ return (end - addr) >> PAGE_SHIFT;

none_mapped:
- mincore_unmapped_range(vma, addr, nr, vec);
- return nr;
+ mincore_unmapped_range(vma, addr, end, vec);
+ return (end - addr) >> PAGE_SHIFT;
}

/*
--
1.7.0.2

--
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Prev: hwmon: f71882fg: properly acquire I/O regions while probing
Next: [PATCH] ksz884x: fix return value of netdev_set_eeprom