md: fix an unsigned compare to allow creation of bitmaps with v1.0 metadata

As page->index is unsigned, this all becomes an unsigned comparison,
which almost always returns an error.

Signed-off-by: Neil Brown <neilb@suse.de>
Cc: Stable <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 1 insertions, 1 deletions

diff --git a/drivers/md/bitmap.c b/drivers/md/bitmap.c
index 927cb34c4805..7c426d07a555 100644
--- a/drivers/md/bitmap.c
+++ b/drivers/md/bitmap.c
@@ -274,7 +274,7 @@ static int write_sb_page(struct bitmap *bitmap, struct page *page, int wait)
                         if (bitmap->offset < 0) {
                                 /* DATA  BITMAP METADATA  */
                                 if (bitmap->offset
-                                    + page->index * (PAGE_SIZE/512)
+                                    + (long)(page->index * (PAGE_SIZE/512))
                                     + size/512 > 0)
                                         /* bitmap runs in to metadata */
                                         return -EINVAL;