is_sync_wait() is used to distinguish between sync and async waits.
Basically sync waits are the ones initialized with init_waitqueue_entry()
and async ones with init_waitqueue_func_entry().  The sync/async
distinction is used only in prepare_to_wait[_exclusive]() and its only
function is to skip setting the current task state if the wait is async.
This has a few problems.

* No one uses it.  None of func_entry users use prepare_to_wait()
  functions, so the code path never gets executed.

* The distinction is bogus.  Maybe back when func_entry is used only
  by aio but it's now also used by epoll and in future possibly by 9p
  and poll/select.

* Taking @state as argument and ignoring it silenly depending on how
  @wait is initialized is just a bad error-prone API.

* It prevents func_entry waits from using wait->private for no good
  reason.

This patch kills is_sync_wait() and the associated code paths from
prepare_to_wait[_exclusive]().  As there was no user of these code paths,
this patch doesn't cause any behavior difference.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Also move wake_up_locked() to be with the related functions

Signed-off-by: Matthew Wilcox <willy@linux.intel.com>

Signed-off-by: Michael Opdenacker <michael@free-electrons.com>
Signed-off-by: Adrian Bunk <bunk@stusta.de>

allyesconfig vmlinux size delta:

  text            data    bss     dec          filename
  20736884        6073834 3075176 29885894     vmlinux.before
  20721009        6073966 3075176 29870151     vmlinux.after

~18 bytes per callsite, 15K of text size (~0.1%) saved.

(as an added bonus this also removes a lockdep annotation.)

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

Create one lock class for all waitqueue locks in the kernel.  Has no effect on
non-lockdep kernels.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

Signed-off-by: Jörn Engel <joern@wohnheim.fh-wedel.de>
Signed-off-by: Adrian Bunk <bunk@stusta.de>

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!