Re: [PATCH 1/5] SCHED: add some "wait..on_bit...timeout()" interfaces.

Ingo Molnar
2014-09-24T07:04:29Z

* NeilBrown <neilb@suse.de> wrote:

> @@ -859,6 +860,8 @@ int wake_bit_function(wait_queue_t *wait, unsigned mode, int sync, void *key);
>
> extern int bit_wait(struct wait_bit_key *);
> extern int bit_wait_io(struct wait_bit_key *);
> +extern int bit_wait_timeout(struct wait_bit_key *);
> +extern int bit_wait_io_timeout(struct wait_bit_key *);
>
> /**
> * wait_on_bit - wait for a bit to be cleared
> diff --git a/kernel/sched/wait.c b/kernel/sched/wait.c
> index 15cab1a4f84e..380678b3cba4 100644
> --- a/kernel/sched/wait.c
> +++ b/kernel/sched/wait.c
> @@ -343,6 +343,18 @@ int __sched out_of_line_wait_on_bit(void *word, int bit,
> }
> EXPORT_SYMBOL(out_of_line_wait_on_bit);
>
> +int __sched out_of_line_wait_on_bit_timeout(
> + void *word, int bit, wait_bit_action_f *action,
> + unsigned mode, unsigned long timeout)
> +{
> + wait_queue_head_t *wq = bit_waitqueue(word, bit);
> + DEFINE_WAIT_BIT(wait, word, bit);
> +
> + wait.key.timeout = jiffies + timeout;
> + return __wait_on_bit(wq, &wait, action, mode);
> +}
> +EXPORT_SYMBOL(out_of_line_wait_on_bit_timeout);
> +
> int __sched
> __wait_on_bit_lock(wait_queue_head_t *wq, struct wait_bit_queue *q,
> wait_bit_action_f *action, unsigned mode)
> @@ -520,3 +532,27 @@ __sched int bit_wait_io(struct wait_bit_key *word)
> return 0;
> }
> EXPORT_SYMBOL(bit_wait_io);
> +
> +__sched int bit_wait_timeout(struct wait_bit_key *word)
> +{
> + unsigned long now = ACCESS_ONCE(jiffies);
> + if (signal_pending_state(current->state, current))
> + return 1;
> + if (time_after_eq(now, word->timeout))
> + return -EAGAIN;
> + schedule_timeout(word->timeout - now);
> + return 0;
> +}
> +EXPORT_SYMBOL(bit_wait_timeout);
> +
> +__sched int bit_wait_io_timeout(struct wait_bit_key *word)
> +{
> + unsigned long now = ACCESS_ONCE(jiffies);
> + if (signal_pending_state(current->state, current))
> + return 1;
> + if (time_after_eq(now, word->timeout))
> + return -EAGAIN;
> + io_schedule_timeout(word->timeout - now);
> + return 0;
> +}
> +EXPORT_SYMBOL(bit_wait_io_timeout);

New scheduler APIs should be exported via EXPORT_SYMBOL_GPL().

Thanks,

Ingo