mincore: apply page table walker on do_mincore()

This patch makes do_mincore() use walk_page_vma(), which reduces many
lines of code by using common page table walk code.

[daeseok.youn@gmail.com: remove unneeded variable 'err']
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Daeseok Youn <daeseok.youn@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 0531ea7..29bc6e4 100644 (file)
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1412,26 +1412,6 @@ int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
        return ret;
 }
 
-int mincore_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
-               unsigned long addr, unsigned long end,
-               unsigned char *vec)
-{
-       spinlock_t *ptl;
-       int ret = 0;
-
-       if (__pmd_trans_huge_lock(pmd, vma, &ptl) == 1) {
-               /*
-                * All logical pages in the range are present
-                * if backed by a huge page.
-                */
-               spin_unlock(ptl);
-               memset(vec, 1, (end - addr) >> PAGE_SHIFT);
-               ret = 1;
-       }
-
-       return ret;
-}
-
 int move_huge_pmd(struct vm_area_struct *vma, struct vm_area_struct *new_vma,
                  unsigned long old_addr,
                  unsigned long new_addr, unsigned long old_end,

diff --git a/mm/mincore.c b/mm/mincore.c
index 46527c0..be25efd 100644 (file)
--- a/mm/mincore.c
+++ b/mm/mincore.c
@@ -19,38 +19,25 @@
 #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)
+static int mincore_hugetlb(pte_t *pte, unsigned long hmask, unsigned long addr,
+                       unsigned long end, struct mm_walk *walk)
 {
 #ifdef CONFIG_HUGETLB_PAGE
-       struct hstate *h;
+       unsigned char present;
+       unsigned char *vec = walk->private;
 
-       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;
-               }
-       }
+       /*
+        * Hugepages under user process are always in RAM and never
+        * swapped out, but theoretically it needs to be checked.
+        */
+       present = pte && !huge_pte_none(huge_ptep_get(pte));
+       for (; addr != end; vec++, addr += PAGE_SIZE)
+               *vec = present;
+       walk->private = vec;
 #else
        BUG();
 #endif
+       return 0;
 }
 
 /*
@@ -94,9 +81,8 @@ static unsigned char mincore_page(struct address_space *mapping, pgoff_t pgoff)
        return present;
 }
 
-static void mincore_unmapped_range(struct vm_area_struct *vma,
-                               unsigned long addr, unsigned long end,
-                               unsigned char *vec)
+static int __mincore_unmapped_range(unsigned long addr, unsigned long end,
+                               struct vm_area_struct *vma, unsigned char *vec)
 {
        unsigned long nr = (end - addr) >> PAGE_SHIFT;
        int i;
@@ -111,23 +97,44 @@ static void mincore_unmapped_range(struct vm_area_struct *vma,
                for (i = 0; i < nr; i++)
                        vec[i] = 0;
        }
+       return nr;
+}
+
+static int mincore_unmapped_range(unsigned long addr, unsigned long end,
+                                  struct mm_walk *walk)
+{
+       walk->private += __mincore_unmapped_range(addr, end,
+                                                 walk->vma, walk->private);
+       return 0;
 }
 
-static void mincore_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
-                       unsigned long addr, unsigned long end,
-                       unsigned char *vec)
+static int mincore_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
+                       struct mm_walk *walk)
 {
-       unsigned long next;
        spinlock_t *ptl;
+       struct vm_area_struct *vma = walk->vma;
        pte_t *ptep;
+       unsigned char *vec = walk->private;
+       int nr = (end - addr) >> PAGE_SHIFT;
+
+       if (pmd_trans_huge_lock(pmd, vma, &ptl) == 1) {
+               memset(vec, 1, nr);
+               spin_unlock(ptl);
+               goto out;
+       }
+
+       if (pmd_trans_unstable(pmd)) {
+               __mincore_unmapped_range(addr, end, vma, vec);
+               goto out;
+       }
 
-       ptep = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
-       do {
+       ptep = pte_offset_map_lock(walk->mm, pmd, addr, &ptl);
+       for (; addr != end; ptep++, addr += PAGE_SIZE) {
                pte_t pte = *ptep;
 
-               next = addr + PAGE_SIZE;
                if (pte_none(pte))
-                       mincore_unmapped_range(vma, addr, next, vec);
+                       __mincore_unmapped_range(addr, addr + PAGE_SIZE,
+                                                vma, vec);
                else if (pte_present(pte))
                        *vec = 1;
                else { /* pte is a swap entry */
@@ -150,69 +157,12 @@ static void mincore_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
                        }
                }
                vec++;
-       } while (ptep++, addr = next, addr != end);
+       }
        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;
-
-       pmd = pmd_offset(pud, addr);
-       do {
-               next = pmd_addr_end(addr, end);
-               if (pmd_trans_huge(*pmd)) {
-                       if (mincore_huge_pmd(vma, pmd, addr, next, vec)) {
-                               vec += (next - addr) >> PAGE_SHIFT;
-                               continue;
-                       }
-                       /* fall through */
-               }
-               if (pmd_none_or_trans_huge_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);
-}
-
-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);
+out:
+       walk->private += nr;
+       cond_resched();
+       return 0;
 }
 
 /*
@@ -224,18 +174,22 @@ static long do_mincore(unsigned long addr, unsigned long pages, unsigned char *v
 {
        struct vm_area_struct *vma;
        unsigned long end;
+       int err;
+       struct mm_walk mincore_walk = {
+               .pmd_entry = mincore_pte_range,
+               .pte_hole = mincore_unmapped_range,
+               .hugetlb_entry = mincore_hugetlb,
+               .private = vec,
+       };
 
        vma = find_vma(current->mm, addr);
        if (!vma || addr < vma->vm_start)
                return -ENOMEM;
-
+       mincore_walk.mm = vma->vm_mm;
        end = min(vma->vm_end, addr + (pages << PAGE_SHIFT));
-
-       if (is_vm_hugetlb_page(vma))
-               mincore_hugetlb_page_range(vma, addr, end, vec);
-       else
-               mincore_page_range(vma, addr, end, vec);
-
+       err = walk_page_range(addr, end, &mincore_walk);
+       if (err < 0)
+               return err;
        return (end - addr) >> PAGE_SHIFT;
 }