releases/4.19.51/mm-cma_debug.c-fix-the-break-condition-in-cma_maxchu.patch

   1 From 6f8b1f3fc9c7097cf634336450e91f1a21a5444c Mon Sep 17 00:00:00 2001
   2 From: Yue Hu <huyue2@yulong.com>
   3 Date: Mon, 13 May 2019 17:16:37 -0700
   4 Subject: mm/cma_debug.c: fix the break condition in cma_maxchunk_get()
   5
   6 [ Upstream commit f0fd50504a54f5548eb666dc16ddf8394e44e4b7 ]
   7
   8 If not find zero bit in find_next_zero_bit(), it will return the size
   9 parameter passed in, so the start bit should be compared with bitmap_maxno
  10 rather than cma->count.  Although getting maxchunk is working fine due to
  11 zero value of order_per_bit currently, the operation will be stuck if
  12 order_per_bit is set as non-zero.
  13
  14 Link: http://lkml.kernel.org/r/20190319092734.276-1-zbestahu@gmail.com
  15 Signed-off-by: Yue Hu <huyue2@yulong.com>
  16 Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
  17 Cc: Michal Hocko <mhocko@suse.com>
  18 Cc: Joe Perches <joe@perches.com>
  19 Cc: David Rientjes <rientjes@google.com>
  20 Cc: Dmitry Safonov <d.safonov@partner.samsung.com>
  21 Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
  22 Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
  23 Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
  24 Signed-off-by: Sasha Levin <sashal@kernel.org>
  25 ---
  26  mm/cma_debug.c | 2 +-
  27  1 file changed, 1 insertion(+), 1 deletion(-)
  28
  29 diff --git a/mm/cma_debug.c b/mm/cma_debug.c
  30 index ad6723e9d110..3e0415076cc9 100644
  31 --- a/mm/cma_debug.c
  32 +++ b/mm/cma_debug.c
  33 @@ -58,7 +58,7 @@ static int cma_maxchunk_get(void *data, u64 *val)
  34         mutex_lock(&cma->lock);
  35         for (;;) {
  36                 start = find_next_zero_bit(cma->bitmap, bitmap_maxno, end);
  37 -               if (start >= cma->count)
  38 +               if (start >= bitmap_maxno)
  39                         break;
  40                 end = find_next_bit(cma->bitmap, bitmap_maxno, start);
  41                 maxchunk = max(end - start, maxchunk);
  42 --
  43 2.20.1
  44