1 files changed, 151 insertions, 112 deletions

diff --git a/mm/mincore.c b/mm/mincore.c
index f77433c20279..9ac42dc6d7b6 100644
--- a/mm/mincore.c
+++ b/mm/mincore.c
@@ -19,6 +19,40 @@
 #include <asm/uaccess.h>
 #include <asm/pgtable.h>
 
+static void mincore_hugetlb_page_range(struct vm_area_struct *vma,
+                                unsigned long addr, unsigned long end,
+                                unsigned char *vec)
+{
+#ifdef CONFIG_HUGETLB_PAGE
+        struct hstate *h;
+
+        h = hstate_vma(vma);
+        while (1) {
+                unsigned char present;
+                pte_t *ptep;
+                /*
+                 * Huge pages are always in RAM for now, but
+                 * theoretically it needs to be checked.
+                 */
+                ptep = huge_pte_offset(current->mm,
+                                       addr & huge_page_mask(h));
+                present = ptep && !huge_pte_none(huge_ptep_get(ptep));
+                while (1) {
+                        *vec = present;
+                        vec++;
+                        addr += PAGE_SIZE;
+                        if (addr == end)
+                                return;
+                        /* check hugepage border */
+                        if (!(addr & ~huge_page_mask(h)))
+                                break;
+                }
+        }
+#else
+        BUG();
+#endif
+}
+
 /*
  * Later we can get more picky about what "in core" means precisely.
  * For now, simply check to see if the page is in the page cache,
@@ -49,145 +83,150 @@ static unsigned char mincore_page(struct address_space *mapping, pgoff_t pgoff)
         return present;
 }
 
-/*
- * Do a chunk of "sys_mincore()". We've already checked
- * all the arguments, we hold the mmap semaphore: we should
- * just return the amount of info we're asked for.
- */
-static long do_mincore(unsigned long addr, unsigned char *vec, unsigned long pages)
+static void mincore_unmapped_range(struct vm_area_struct *vma,
+                                unsigned long addr, unsigned long end,
+                                unsigned char *vec)
 {
-        pgd_t *pgd;
-        pud_t *pud;
-        pmd_t *pmd;
-        pte_t *ptep;
-        spinlock_t *ptl;
-        unsigned long nr;
+        unsigned long nr = (end - addr) >> PAGE_SHIFT;
         int i;
-        pgoff_t pgoff;
-        struct vm_area_struct *vma = find_vma(current->mm, addr);
 
-        /*
-         * find_vma() didn't find anything above us, or we're
-         * in an unmapped hole in the address space: ENOMEM.
-         */
-        if (!vma || addr < vma->vm_start)
-                return -ENOMEM;
-
-#ifdef CONFIG_HUGETLB_PAGE
-        if (is_vm_hugetlb_page(vma)) {
-                struct hstate *h;
-                unsigned long nr_huge;
-                unsigned char present;
+        if (vma->vm_file) {
+                pgoff_t pgoff;
 
-                i = 0;
-                nr = min(pages, (vma->vm_end - addr) >> PAGE_SHIFT);
-                h = hstate_vma(vma);
-                nr_huge = ((addr + pages * PAGE_SIZE - 1) >> huge_page_shift(h))
-                          - (addr >> huge_page_shift(h)) + 1;
-                nr_huge = min(nr_huge,
-                              (vma->vm_end - addr) >> huge_page_shift(h));
-                while (1) {
-                        /* hugepage always in RAM for now,
-                         * but generally it needs to be check */
-                        ptep = huge_pte_offset(current->mm,
-                                               addr & huge_page_mask(h));
-                        present = !!(ptep &&
-                                     !huge_pte_none(huge_ptep_get(ptep)));
-                        while (1) {
-                                vec[i++] = present;
-                                addr += PAGE_SIZE;
-                                /* reach buffer limit */
-                                if (i == nr)
-                                        return nr;
-                                /* check hugepage border */
-                                if (!((addr & ~huge_page_mask(h))
-                                      >> PAGE_SHIFT))
-                                        break;
-                        }
-                }
-                return nr;
+                pgoff = linear_page_index(vma, addr);
+                for (i = 0; i < nr; i++, pgoff++)
+                        vec[i] = mincore_page(vma->vm_file->f_mapping, pgoff);
+        } else {
+                for (i = 0; i < nr; i++)
+                        vec[i] = 0;
         }
-#endif
-
-        /*
-         * Calculate how many pages there are left in the last level of the
-         * PTE array for our address.
-         */
-        nr = PTRS_PER_PTE - ((addr >> PAGE_SHIFT) & (PTRS_PER_PTE-1));
-
-        /*
-         * Don't overrun this vma
-         */
-        nr = min(nr, (vma->vm_end - addr) >> PAGE_SHIFT);
-
-        /*
-         * Don't return more than the caller asked for
-         */
-        nr = min(nr, pages);
+}
 
-        pgd = pgd_offset(vma->vm_mm, addr);
-        if (pgd_none_or_clear_bad(pgd))
-                goto none_mapped;
-        pud = pud_offset(pgd, addr);
-        if (pud_none_or_clear_bad(pud))
-                goto none_mapped;
-        pmd = pmd_offset(pud, addr);
-        if (pmd_none_or_clear_bad(pmd))
-                goto none_mapped;
+static void mincore_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
+                        unsigned long addr, unsigned long end,
+                        unsigned char *vec)
+{
+        unsigned long next;
+        spinlock_t *ptl;
+        pte_t *ptep;
 
         ptep = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
-        for (i = 0; i < nr; i++, ptep++, addr += PAGE_SIZE) {
-                unsigned char present;
+        do {
                 pte_t pte = *ptep;
+                pgoff_t pgoff;
 
-                if (pte_present(pte)) {
-                        present = 1;
-
-                } else if (pte_none(pte)) {
-                        if (vma->vm_file) {
-                                pgoff = linear_page_index(vma, addr);
-                                present = mincore_page(vma->vm_file->f_mapping,
-                                                        pgoff);
-                        } else
-                                present = 0;
-
-                } else if (pte_file(pte)) {
+                next = addr + PAGE_SIZE;
+                if (pte_none(pte))
+                        mincore_unmapped_range(vma, addr, next, vec);
+                else if (pte_present(pte))
+                        *vec = 1;
+                else if (pte_file(pte)) {
                         pgoff = pte_to_pgoff(pte);
-                        present = 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 */
-                                present = 1;
+                                *vec = 1;
                         } else {
 #ifdef CONFIG_SWAP
                                 pgoff = entry.val;
-                                present = mincore_page(&swapper_space, pgoff);
+                                *vec = mincore_page(&swapper_space, pgoff);
 #else
                                 WARN_ON(1);
-                                present = 1;
+                                *vec = 1;
 #endif
                         }
                 }
+                vec++;
+        } while (ptep++, addr = next, addr != end);
+        pte_unmap_unlock(ptep - 1, ptl);
+}
 
-                vec[i] = present;
-        }
-        pte_unmap_unlock(ptep-1, ptl);
+static void mincore_pmd_range(struct vm_area_struct *vma, pud_t *pud,
+                        unsigned long addr, unsigned long end,
+                        unsigned char *vec)
+{
+        unsigned long next;
+        pmd_t *pmd;
 
-        return nr;
+        pmd = pmd_offset(pud, addr);
+        do {
+                next = pmd_addr_end(addr, end);
+                if (pmd_none_or_clear_bad(pmd))
+                        mincore_unmapped_range(vma, addr, next, vec);
+                else
+                        mincore_pte_range(vma, pmd, addr, next, vec);
+                vec += (next - addr) >> PAGE_SHIFT;
+        } while (pmd++, addr = next, addr != end);
+}
 
-none_mapped:
-        if (vma->vm_file) {
-                pgoff = linear_page_index(vma, addr);
-                for (i = 0; i < nr; i++, pgoff++)
-                        vec[i] = mincore_page(vma->vm_file->f_mapping, pgoff);
-        } else {
-                for (i = 0; i < nr; i++)
-                        vec[i] = 0;
+static void mincore_pud_range(struct vm_area_struct *vma, pgd_t *pgd,
+                        unsigned long addr, unsigned long end,
+                        unsigned char *vec)
+{
+        unsigned long next;
+        pud_t *pud;
+
+        pud = pud_offset(pgd, addr);
+        do {
+                next = pud_addr_end(addr, end);
+                if (pud_none_or_clear_bad(pud))
+                        mincore_unmapped_range(vma, addr, next, vec);
+                else
+                        mincore_pmd_range(vma, pud, addr, next, vec);
+                vec += (next - addr) >> PAGE_SHIFT;
+        } while (pud++, addr = next, addr != end);
+}
+
+static void mincore_page_range(struct vm_area_struct *vma,
+                        unsigned long addr, unsigned long end,
+                        unsigned char *vec)
+{
+        unsigned long next;
+        pgd_t *pgd;
+
+        pgd = pgd_offset(vma->vm_mm, addr);
+        do {
+                next = pgd_addr_end(addr, end);
+                if (pgd_none_or_clear_bad(pgd))
+                        mincore_unmapped_range(vma, addr, next, vec);
+                else
+                        mincore_pud_range(vma, pgd, addr, next, vec);
+                vec += (next - addr) >> PAGE_SHIFT;
+        } while (pgd++, addr = next, addr != end);
+}
+
+/*
+ * Do a chunk of "sys_mincore()". We've already checked
+ * all the arguments, we hold the mmap semaphore: we should
+ * just return the amount of info we're asked for.
+ */
+static long do_mincore(unsigned long addr, unsigned long pages, unsigned char *vec)
+{
+        struct vm_area_struct *vma;
+        unsigned long end;
+
+        vma = find_vma(current->mm, addr);
+        if (!vma || addr < vma->vm_start)
+                return -ENOMEM;
+
+        end = min(vma->vm_end, addr + (pages << PAGE_SHIFT));
+
+        if (is_vm_hugetlb_page(vma)) {
+                mincore_hugetlb_page_range(vma, addr, end, vec);
+                return (end - addr) >> PAGE_SHIFT;
         }
 
-        return nr;
+        end = pmd_addr_end(addr, end);
+
+        if (is_vm_hugetlb_page(vma))
+                mincore_hugetlb_page_range(vma, addr, end, vec);
+        else
+                mincore_page_range(vma, addr, end, vec);
+
+        return (end - addr) >> PAGE_SHIFT;
 }
 
 /*
@@ -247,7 +286,7 @@ SYSCALL_DEFINE3(mincore, unsigned long, start, size_t, len,
                  * the temporary buffer size.
                  */
                 down_read(&current->mm->mmap_sem);
-                retval = do_mincore(start, tmp, min(pages, PAGE_SIZE));
+                retval = do_mincore(start, min(pages, PAGE_SIZE), tmp);
                 up_read(&current->mm->mmap_sem);
 
                 if (retval <= 0)