Messages in this thread | | | Date | Sun, 4 Sep 2022 11:54:57 +0200 | From | Ingo Molnar <> | Subject | Re: [PATCH v3 5/6] sched/wait: Add wait_event_state() |
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* Peter Zijlstra <peterz@infradead.org> wrote:
> Allows waiting with a custom @state. > > Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> > --- > include/linux/wait.h | 28 ++++++++++++++++++++++++++++ > 1 file changed, 28 insertions(+) > > --- a/include/linux/wait.h > +++ b/include/linux/wait.h > @@ -931,6 +931,34 @@ extern int do_wait_intr_irq(wait_queue_h > __ret; \ > }) > > +#define __wait_event_state(wq, condition, state) \ > + ___wait_event(wq, condition, state, 0, 0, schedule()) > + > +/** > + * wait_event_state - sleep until a condition gets true > + * @wq_head: the waitqueue to wait on > + * @condition: a C expression for the event to wait for > + * @state: state to sleep in > + * > + * The process is put to sleep (@state) until the @condition evaluates to true > + * or a signal is received. The @condition is checked each time the waitqueue > + * @wq_head is woken up.
Documentation inconsistency nit: if TASK_INTERRUPTIBLE isn't in @state then we won't wake up when a signal is received. This probably got copy-pasted from a signal variant.
> + * > + * wake_up() has to be called after changing any variable that could > + * change the result of the wait condition. > + * > + * The function will return -ERESTARTSYS if it was interrupted by a > + * signal and 0 if @condition evaluated to true.
That's not unconditionally true either if !TASK_INTERRUPTIBLE.
> +#define wait_event_state(wq_head, condition, state) \ > +({ \ > + int __ret = 0; \ > + might_sleep(); \
Very small style consistency nit, the above should have a newline after local variables:
> +#define wait_event_state(wq_head, condition, state) \ > +({ \ > + int __ret = 0; \ > + \ > + might_sleep(); \
Like most (but not all ... :-/ ) of the existing primitives have.
Thanks,
Ingo
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