From mboxrd@z Thu Jan 1 00:00:00 1970 From: NeilBrown Subject: [PATCH 004 of 6] md: Use ffz instead of find_first_set to convert multiplier to shift. Date: Fri, 29 Sep 2006 12:53:16 +1000 Message-ID: <1060929025316.15249@suse.de> References: <20060929125047.14064.patches@notabene> Return-path: Sender: linux-raid-owner@vger.kernel.org To: Andrew Morton Cc: linux-raid@vger.kernel.org, linux-kernel@vger.kernel.org List-Id: linux-raid.ids From: Paul Clements find_first_set doesn't find the least-significant bit on bigendian machines, so it is really wrong to use it. ffs is closer, but takes an 'int' and we have a 'unsigned long'. So use ffz(~X) to convert a chunksize into a chunkshift. Signed-off-by: Neil Brown ### Diffstat output ./drivers/md/bitmap.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff .prev/drivers/md/bitmap.c ./drivers/md/bitmap.c --- .prev/drivers/md/bitmap.c 2006-09-29 11:44:38.000000000 +1000 +++ ./drivers/md/bitmap.c 2006-09-29 11:49:40.000000000 +1000 @@ -1444,8 +1444,7 @@ int bitmap_create(mddev_t *mddev) if (err) goto error; - bitmap->chunkshift = find_first_bit(&bitmap->chunksize, - sizeof(bitmap->chunksize)); + bitmap->chunkshift = ffz(~bitmap->chunksize); /* now that chunksize and chunkshift are set, we can use these macros */ chunks = (blocks + CHUNK_BLOCK_RATIO(bitmap) - 1) /