some swapfile patches

Here comes a series of 13 swap patches, mainly to mm/swapfile.c, based
on 2.6.13-rc2-mm1 but applying also to 2.6.13-rc2.  I don't think any
of them are important enough for 2.6.13, though the first half are
straightforward.  The main thrust is to scan the swap_map lockless,
to stop the infamous latency in get_swap_page.  But they keep to the
familiar swap allocation algorithm, so no change to macro-latency.

 Documentation/vm/locking |   15 -
 include/linux/swap.h     |   22 --
 kernel/power/swsusp.c    |   12 -
 mm/filemap.c             |    7 
 mm/rmap.c                |    3 
 mm/swapfile.c            |  410 +++++++++++++++++++++++++----------------------
 6 files changed, 246 insertions(+), 223 deletions(-)

Strictly, arch/m68k/atari/stram.c should also be in that list.
But CONFIG_STRAM_SWAP is under CONFIG_BROKEN, and its reference to
swap_vfsmnt implies it hasn't been built since 2.5.1.  Time again to
cajole the m68k people into removing that code - if the mtd driver
doesn't already satisfy their need in a much better way, it cannot
be far off (need? hardly, if unbuilt in 3.5 years).

Hugh