[patch 11/31] Fix calculation for size of filemap_attr array in md/bitmap.

[Greg KH <gregkh@suse.de>]

[-- Attachment #1: fix-calculation-for-size-of-filemap_attr-array-in-md-bitmap.patch --]
[-- Type: text/plain, Size: 977 bytes --]

-stable review patch.  If anyone has any objections, please let us know.

------------------
From: Neil Brown <neilb@suse.de>

If 'num_pages' were ever 1 more than a multiple of 8 (32bit platforms)
for of 16 (64 bit platforms). filemap_attr would be allocated one
'unsigned long' shorter than required.  We need a round-up in there.


Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
 drivers/md/bitmap.c |    4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

--- a/drivers/md/bitmap.c
+++ b/drivers/md/bitmap.c
@@ -863,9 +863,7 @@ static int bitmap_init_from_disk(struct 
 
 	/* We need 4 bits per page, rounded up to a multiple of sizeof(unsigned long) */
 	bitmap->filemap_attr = kzalloc(
-		(((num_pages*4/8)+sizeof(unsigned long)-1)
-		 /sizeof(unsigned long))
-		*sizeof(unsigned long),
+		roundup( DIV_ROUND_UP(num_pages*4, 8), sizeof(unsigned long)),
 		GFP_KERNEL);
 	if (!bitmap->filemap_attr)
 		goto out;

--