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, 8 insertions, 7 deletions

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 97da0302cf51..87b0ef253607 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1013,13 +1013,14 @@ extern int access_process_vm(struct task_struct *tsk, unsigned long addr, void *
 extern int access_remote_vm(struct mm_struct *mm, unsigned long addr,
                 void *buf, int len, int write);
 
-int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
-                     unsigned long start, int len, unsigned int foll_flags,
-                     struct page **pages, struct vm_area_struct **vmas,
-                     int *nonblocking);
-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,
+                      unsigned int foll_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,
+                    int write, int force, struct page **pages,
+                    struct vm_area_struct **vmas);
 int get_user_pages_fast(unsigned long start, int nr_pages, int write,
                         struct page **pages);
 struct kvec;