mincore: pass ranges as start,end address pairs

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@cmpxchg.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 27 insertions, 30 deletions

diff --git a/mm/mincore.c b/mm/mincore.c
index a0c4c10bbab7..211604adc23c 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))
@@ -183,12 +180,12 @@ 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;
 }
 
 /*