From: swkhack <swkhack@gmail.com>
Date: Thu, 13 Jun 2019 15:56:08 -0700
Subject: mm/mlock.c: change count_mm_mlocked_page_nr return type
Git-commit: 0874bb49bb21bf24deda853e8bf61b8325e24bcb
Patch-mainline: v5.2-rc5
References: bsc#1148527, VM Functionality

On a 64-bit machine the value of "vma->vm_end - vma->vm_start" may be
negative when using 32 bit ints and the "count >> PAGE_SHIFT"'s result
will be wrong.  So change the local variable and return value to
unsigned long to fix the problem.

Link: http://lkml.kernel.org/r/20190513023701.83056-1-swkhack@gmail.com
Fixes: 0cf2f6f6dc60 ("mm: mlock: check against vma for actual mlock() size")
Signed-off-by: swkhack <swkhack@gmail.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
---
 mm/mlock.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/mm/mlock.c
+++ b/mm/mlock.c
@@ -631,11 +631,11 @@ static int apply_vma_lock_flags(unsigned
  * is also counted.
  * Return value: previously mlocked page counts
  */
-static int count_mm_mlocked_page_nr(struct mm_struct *mm,
+static unsigned long count_mm_mlocked_page_nr(struct mm_struct *mm,
 		unsigned long start, size_t len)
 {
 	struct vm_area_struct *vma;
-	int count = 0;
+	unsigned long count = 0;
 
 	if (mm == NULL)
 		mm = current->mm;