[S390] extend virtual timer interface by mod_virt_timer_periodic
In case mod_virt_timer is used to add a non pending timer the timer is always added as a one-shot timer. If mod_virt_timer is used for periodic timers they may therfore be degraded to one-shot timers. Add mod_virt_timer_periodic to the interface to allow safe re-programming of the interval value. Signed-off-by: Jan Glauber <jang@linux.vnet.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
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0436230148
Коммит
b6ecfa9273
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@ -41,6 +41,7 @@ extern void init_virt_timer(struct vtimer_list *timer);
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extern void add_virt_timer(void *new);
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extern void add_virt_timer_periodic(void *new);
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extern int mod_virt_timer(struct vtimer_list *timer, __u64 expires);
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extern int mod_virt_timer_periodic(struct vtimer_list *timer, __u64 expires);
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extern int del_virt_timer(struct vtimer_list *timer);
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extern void init_cpu_vtimer(void);
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@ -425,17 +425,7 @@ void add_virt_timer_periodic(void *new)
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}
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EXPORT_SYMBOL(add_virt_timer_periodic);
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/*
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* If we change a pending timer the function must be called on the CPU
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* where the timer is running on, e.g. by smp_call_function_single()
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*
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* The original mod_timer adds the timer if it is not pending. For
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* compatibility we do the same. The timer will be added on the current
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* CPU as a oneshot timer.
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*
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* returns whether it has modified a pending timer (1) or not (0)
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*/
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int mod_virt_timer(struct vtimer_list *timer, __u64 expires)
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int __mod_vtimer(struct vtimer_list *timer, __u64 expires, int periodic)
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{
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struct vtimer_queue *vq;
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unsigned long flags;
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@ -444,39 +434,35 @@ int mod_virt_timer(struct vtimer_list *timer, __u64 expires)
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BUG_ON(!timer->function);
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BUG_ON(!expires || expires > VTIMER_MAX_SLICE);
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/*
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* This is a common optimization triggered by the
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* networking code - if the timer is re-modified
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* to be the same thing then just return:
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*/
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if (timer->expires == expires && vtimer_pending(timer))
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return 1;
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cpu = get_cpu();
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vq = &per_cpu(virt_cpu_timer, cpu);
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/* check if we run on the right CPU */
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BUG_ON(timer->cpu != cpu);
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/* disable interrupts before test if timer is pending */
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spin_lock_irqsave(&vq->lock, flags);
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/* if timer isn't pending add it on the current CPU */
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if (!vtimer_pending(timer)) {
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spin_unlock_irqrestore(&vq->lock, flags);
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/* we do not activate an interval timer with mod_virt_timer */
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timer->interval = 0;
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if (periodic)
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timer->interval = expires;
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else
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timer->interval = 0;
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timer->expires = expires;
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timer->cpu = cpu;
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internal_add_vtimer(timer);
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return 0;
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}
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/* check if we run on the right CPU */
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BUG_ON(timer->cpu != cpu);
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list_del_init(&timer->entry);
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timer->expires = expires;
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/* also change the interval if we have an interval timer */
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if (timer->interval)
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if (periodic)
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timer->interval = expires;
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/* the timer can't expire anymore so we can release the lock */
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@ -484,8 +470,31 @@ int mod_virt_timer(struct vtimer_list *timer, __u64 expires)
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internal_add_vtimer(timer);
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return 1;
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}
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/*
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* If we change a pending timer the function must be called on the CPU
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* where the timer is running on.
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*
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* returns whether it has modified a pending timer (1) or not (0)
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*/
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int mod_virt_timer(struct vtimer_list *timer, __u64 expires)
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{
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return __mod_vtimer(timer, expires, 0);
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}
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EXPORT_SYMBOL(mod_virt_timer);
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/*
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* If we change a pending timer the function must be called on the CPU
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* where the timer is running on.
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*
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* returns whether it has modified a pending timer (1) or not (0)
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*/
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int mod_virt_timer_periodic(struct vtimer_list *timer, __u64 expires)
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{
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return __mod_vtimer(timer, expires, 1);
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}
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EXPORT_SYMBOL(mod_virt_timer_periodic);
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/*
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* delete a virtual timer
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*
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