[PATCH V2 08/12] badblocks: fix merge issue when new badblocks align with pre+1

[Zheng Qixing]

From: Li Nan <linan...@huawei.com>

There is a merge issue when adding badblocks as follow:
  echo 0 10 > bad_blocks
  echo 30 10 > bad_blocks
  echo 20 10 > bad_blocks
  cat bad_blocks
  0 10
  20 10    //should be merged with (30 10)
  30 10

In this case, if new badblocks does not intersect with prev, it is added
by insert_at(). If there is an intersection with prev+1, the merge will
be processed in the next re_insert loop.

However, when the end of the new badblocks is exactly equal to the offset
of prev+1, no further re_insert loop occurs, and the two badblocks are not
merge.

Fix it by inc prev, badblocks can be merged during the subsequent code.

Fixes: aa511ff8218b ("badblocks: switch to the improved badblock handling code")
Signed-off-by: Li Nan <linan...@huawei.com>
Reviewed-by: Yu Kuai <yuku...@huawei.com>
---
 block/badblocks.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/block/badblocks.c b/block/badblocks.c
index 57e9edf9b848..92bd43f7fff1 100644
--- a/block/badblocks.c
+++ b/block/badblocks.c
@@ -892,7 +892,7 @@ static int _badblocks_set(struct badblocks *bb, sector_t s, 
int sectors,
                len = insert_at(bb, 0, &bad);
                bb->count++;
                added++;
-               hint = 0;
+               hint = ++prev;
                goto update_sectors;
        }
 
@@ -947,7 +947,7 @@ static int _badblocks_set(struct badblocks *bb, sector_t s, 
int sectors,
        len = insert_at(bb, prev + 1, &bad);
        bb->count++;
        added++;
-       hint = prev + 1;
+       hint = ++prev;
 
 update_sectors:
        s += len;
-- 
2.39.2