Kernel lock order

[Zoltan Menyhart]

Is there a list describing the lock hierarchy ?
If not:
Does do_swap_page() (in mm/memory.c) release mm->page_table_lock because
one cannot hold this lock when lookup_swap_cache() ... __find_get_page()
takes pagecache_lock ? Or does it do only for shorten the locked path ?
(Can I keep mm->page_table_lock when I call __find_get_page() ?)

Thanks,

Zoltan Menyhart