Is there a primitive to atomically release a spinlock and go to sleep?

Is there a primitive to atomically release a spinlock and go to sleep?

[David Nicol]

I'm trying to do something involving multiple kthreads in an ioctl
handler, and I want to avoid the
race condition between the third and fourth steps of

    acquire mutex
    add &self to a list of threads which will get awakened by
something else that is also aware of this list
    release mutex
    go to sleep

Is there a standard atomic go-to-sleep function that takes as a
parameter a pointer to  spinlock to release after its state is set to
TASK_INTERRUPTIBLE?

Re: Is there a primitive to atomically release a spinlock and go to sleep?

[Andy Lutomirski]

David Nicol wrote:
> I'm trying to do something involving multiple kthreads in an ioctl
> handler, and I want to avoid the
> race condition between the third and fourth steps of
> 
>     acquire mutex
>     add &self to a list of threads which will get awakened by
> something else that is also aware of this list
>     release mutex
>     go to sleep
> 
> Is there a standard atomic go-to-sleep function that takes as a
> parameter a pointer to  spinlock to release after its state is set to
> TASK_INTERRUPTIBLE?

That wouldn't be enough -- the other thread could try to wake you up before you're even in the list of threads.

Look at wait_event_*() or read this:

http://book.chinaunix.net/special/ebook/PrenticeHall/PrenticeHallPTRTheLinuxKernelPrimer/0131181637/ch03lev1sec7.html

--Andy