mm: use long type for page counts in mm_populate() and get_user_pages()

Use long type for page counts in mm_populate() so as to avoid integer
overflow when running the following test code:

int main(void) {
  void *p = mmap(NULL, 0x100000000000, PROT_READ,
                 MAP_PRIVATE | MAP_ANON, -1, 0);
  printf("p: %p\n", p);
  mlockall(MCL_CURRENT);
  printf("done\n");
  return 0;
}

Signed-off-by: Michel Lespinasse <walken@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 9 insertions, 9 deletions

diff --git a/mm/memory.c b/mm/memory.c
index 7bd22a621817..bc929dbad215 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1677,15 +1677,15 @@ static inline int stack_guard_page(struct vm_area_struct *vma, unsigned long add
  * instead of __get_user_pages. __get_user_pages should be used only if
  * you need some special @gup_flags.
  */
-int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
-                     unsigned long start, int nr_pages, unsigned int gup_flags,
-                     struct page **pages, struct vm_area_struct **vmas,
-                     int *nonblocking)
+long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
+                unsigned long start, unsigned long nr_pages,
+                unsigned int gup_flags, struct page **pages,
+                struct vm_area_struct **vmas, int *nonblocking)
 {
-        int i;
+        long i;
         unsigned long vm_flags;
 
-        if (nr_pages <= 0)
+        if (!nr_pages)
                 return 0;
 
         VM_BUG_ON(!!pages != !!(gup_flags & FOLL_GET));
@@ -1981,9 +1981,9 @@ int fixup_user_fault(struct task_struct *tsk, struct mm_struct *mm,
  *
  * See also get_user_pages_fast, for performance critical applications.
  */
-int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
-                unsigned long start, int nr_pages, int write, int force,
-                struct page **pages, struct vm_area_struct **vmas)
+long get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
+                unsigned long start, unsigned long nr_pages, int write,
+                int force, struct page **pages, struct vm_area_struct **vmas)
 {
         int flags = FOLL_TOUCH;