Optimise ffs(x) by using fls(x & x - 1) which we optimise to use the SCAN
instruction.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>