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Commit 505fa2c4 authored by Neil Brown's avatar Neil Brown Committed by Linus Torvalds
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[PATCH] md: fix calculation for size of filemap_attr array in md/bitmap 



If 'num_pages' were ever 1 more than a multiple of 8 (32bit platforms)
or 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: default avatarNeil Brown <neilb@suse.de>
Cc: <stable@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent b6550777

drivers/md/bitmap.c

+1 −3
Original line number Diff line number Diff line
@@ -863,9 +863,7 @@ static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start) 


	/* 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;