Move the slow paths of wait_on_bit() and wait_on_bit_lock() out of line.
Also uninline wake_up_bit() to reduce the number of callsites generated,
and adjust loop startup in __wait_on_bit_lock() to properly reflect its
usage in the contention case.

Incremental atop the fastcall and wait_on_bit_lock()/test_and_set_bit()
fixes.  Successfully tested on x86-64.

Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>