mm: mincore: use PAGE_SIZE instead of PAGE_CACHE_SIZE

This is a RFC patch, because current PAGE_SIZE is equal to PAGE_CACHE_SIZE, there isn't any difference and issue when running.

However, the current code mixes these two aligned_size inconsistently, and if they are not equal in future mincore_unmapped_range() would check more file pages than wanted.

According to man-page, mincore uses PAGE_SIZE as its size unit, so this patch uses PAGE_SIZE instead of PAGE_CACHE_SIZE.

Signed-off-by Weijie Yang <[email protected]>

---
 mm/mincore.c |   19 +++++++++++++------
 1 files changed, 13 insertions(+), 6 deletions(-)

mm/mincore.c +13 -7

index 725c809..8c19bce 100644
@@ -102,11 +102,18 @@ static void mincore_unmapped_range(struct vm_area_struct *vma,
        int i;
 
        if (vma->vm_file) {
-               pgoff_t pgoff;
+               pgoff_t pgoff, pgoff_end;
+               int j, count;
+               unsigned char res;
 
+               count = 1 << (PAGE_CACHE_SHIFT - PAGE_SHIFT);
                pgoff = linear_page_index(vma, addr);
-               for (i = 0; i < nr; i++, pgoff++)
-                       vec[i] = mincore_page(vma->vm_file->f_mapping, pgoff);
+               pgoff_end = linear_page_index(vma, end);
+               for (i = 0; pgoff < pgoff_end; pgoff++) {
+                       res = mincore_page(vma->vm_file->f_mapping, pgoff);
+                       for (j = 0; j < count; j++)
+                               vec[i++] = res;
+               }
        } else {
                for (i = 0; i < nr; i++)
                        vec[i] = 0;

@@ -258,7 +265,7 @@ static long do_mincore(unsigned long addr, unsigned long pages, unsigned char *v
  * return values:
  *  zero    - success
  *  -EFAULT - vec points to an illegal address
- *  -EINVAL - addr is not a multiple of PAGE_CACHE_SIZE
+ *  -EINVAL - addr is not a multiple of PAGE_SIZE
  *  -ENOMEM - Addresses in the range [addr, addr + len] are
  *             invalid for the address space of this process, or
  *             specify one or more pages which are not currently

@@ -273,14 +280,14 @@ SYSCALL_DEFINE3(mincore, unsigned long, start, size_t, len,
        unsigned char *tmp;
 
        /* Check the start address: needs to be page-aligned.. */
-       if (start & ~PAGE_CACHE_MASK)
+       if (start & ~PAGE_MASK)
                return -EINVAL;
 
        /* ..and we need to be passed a valid user-space range */
        if (!access_ok(VERIFY_READ, (void __user *) start, len))
                return -ENOMEM;
 
-       /* This also avoids any overflows on PAGE_CACHE_ALIGN */
+       /* This also avoids any overflows on PAGE_ALIGN */
        pages = len >> PAGE_SHIFT;
        pages += (len & ~PAGE_MASK) != 0;
 
--

1.7.0.4