linux-stable.git/include/linux/wait.h, branch linux-2.6.24.y

lockdep: annotate epoll

2008-02-08T19:46:25+00:00

patch 0ccf831cbee94df9c5006dd46248c0f07847dd7c in mainline.

On Sat, 2008-01-05 at 13:35 -0800, Davide Libenzi wrote:

> I remember I talked with Arjan about this time ago. Basically, since 1)
> you can drop an epoll fd inside another epoll fd 2) callback-based wakeups
> are used, you can see a wake_up() from inside another wake_up(), but they
> will never refer to the same lock instance.
> Think about:
>
> 	dfd = socket(...);
> 	efd1 = epoll_create();
> 	efd2 = epoll_create();
> 	epoll_ctl(efd1, EPOLL_CTL_ADD, dfd, ...);
> 	epoll_ctl(efd2, EPOLL_CTL_ADD, efd1, ...);
>
> When a packet arrives to the device underneath "dfd", the net code will
> issue a wake_up() on its poll wake list. Epoll (efd1) has installed a
> callback wakeup entry on that queue, and the wake_up() performed by the
> "dfd" net code will end up in ep_poll_callback(). At this point epoll
> (efd1) notices that it may have some event ready, so it needs to wake up
> the waiters on its poll wait list (efd2). So it calls ep_poll_safewake()
> that ends up in another wake_up(), after having checked about the
> recursion constraints. That are, no more than EP_MAX_POLLWAKE_NESTS, to
> avoid stack blasting. Never hit the same queue, to avoid loops like:
>
> 	epoll_ctl(efd2, EPOLL_CTL_ADD, efd1, ...);
> 	epoll_ctl(efd3, EPOLL_CTL_ADD, efd2, ...);
> 	epoll_ctl(efd4, EPOLL_CTL_ADD, efd3, ...);
> 	epoll_ctl(efd1, EPOLL_CTL_ADD, efd4, ...);
>
> The code "if (tncur->wq == wq || ..." prevents re-entering the same
> queue/lock.

Since the epoll code is very careful to not nest same instance locks
allow the recursion.

Signed-off-by: Peter Zijlstra 
Tested-by: Stefan Richter 
Acked-by: Davide Libenzi 
Signed-off-by: Andrew Morton 
Signed-off-by: Greg Kroah-Hartman

sched: clean up sleep_on() APIs

2007-07-09T16:52:01+00:00

clean up the sleep_on() APIs:

 - do not use fastcall
 - replace fragile macro magic with proper inline functions

Signed-off-by: Ingo Molnar

[PATCH] lockdep: annotate DECLARE_WAIT_QUEUE_HEAD

2006-10-30T20:08:40+00:00

kernel: INFO: trying to register non-static key.
kernel: the code is fine but needs lockdep annotation.
kernel: turning off the locking correctness validator.
kernel:  [] show_trace_log_lvl+0x58/0x16a
kernel:  [] show_trace+0xd/0x10
kernel:  [] dump_stack+0x19/0x1b
kernel:  [] __lock_acquire+0xf0/0x90d
kernel:  [] lock_acquire+0x4b/0x6b
kernel:  [] _spin_lock_irqsave+0x22/0x32
kernel:  [] prepare_to_wait+0x17/0x4b
kernel:  [] lpfc_do_work+0xdd/0xcc2 [lpfc]
kernel:  [] kthread+0xc3/0xf2
kernel:  [] kernel_thread_helper+0x5/0xb

Another case of non-static lockdep keys; duplicate the paradigm set by
DECLARE_COMPLETION_ONSTACK and introduce DECLARE_WAIT_QUEUE_HEAD_ONSTACK.

Signed-off-by: Peter Zijlstra 
Cc: Greg KH 
Cc: Markus Lidel 
Acked-by: Ingo Molnar 
Cc: Arjan van de Ven 
Cc: James Bottomley 
Cc: Marcel Holtmann 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] uninline init_waitqueue_head()

2006-07-10T20:24:25+00:00

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 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] lockdep: annotate waitqueues

2006-07-03T22:27:07+00:00

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

Signed-off-by: Ingo Molnar 
Signed-off-by: Arjan van de Ven 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] lockdep: locking init debugging improvement

2006-07-03T22:27:02+00:00

Locking init improvement:

 - introduce and use __SPIN_LOCK_UNLOCKED for array initializations,
   to pass in the name string of locks, used by debugging

Signed-off-by: Ingo Molnar 
Signed-off-by: Arjan van de Ven 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Don't include linux/config.h from anywhere else in include/

2006-04-26T11:56:16+00:00

Signed-off-by: David Woodhouse

[PATCH] fix remaining missing includes

2005-11-07T15:53:41+00:00

Fix more include file problems that surfaced since I submitted the previous
fix-missing-includes.patch.  This should now allow not to include sched.h
from module.h, which is done by a followup patch.

Signed-off-by: Tim Schmielau 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] aio: make wait_queue ->task ->private

2005-06-23T16:45:34+00:00

In the upcoming aio_down patch, it is useful to store a private data
pointer in the kiocb's wait_queue.  Since we provide our own wake up
function and do not require the task_struct pointer, it makes sense to
convert the task pointer into a generic private pointer.

Signed-off-by: Benjamin LaHaise 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] Cleanup DEFINE_WAIT

2005-05-25T00:05:20+00:00

Use LIST_HEAD_INIT rather than doing it by hand in DEFINE_WAIT.

Signed-off-by: Paolo 'Blaisorblade' Giarrusso 
Signed-off-by: Linus Torvalds