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Commit e52b1db3 authored by Tejun Heo's avatar Tejun Heo Committed by Thomas Gleixner
Browse files

timer: Generalize timer->base flags handling 



To prepare for addition of another flag, generalize timer->base flags
handling.

* Rename from TBASE_*_FLAG to TIMER_* and make them LU constants.

* Define and use TIMER_FLAG_MASK for flags masking so that multiple
  flags can be handled correctly.

* Don't dereference timer->base directly even if
  !tbase_get_deferrable().  All two such places are already passed in
  @base, so use it instead.

* Make sure tvec_base's alignment is large enough for timer->base
  flags using BUILD_BUG_ON().

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Cc: torvalds@linux-foundation.org
Cc: peterz@infradead.org
Link: http://lkml.kernel.org/r/1344449428-24962-2-git-send-email-tj@kernel.org


Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent eec19d1a

include/linux/timer.h

+4 −2
Original line number Diff line number Diff line
@@ -58,7 +58,9 @@ extern struct tvec_base boot_tvec_bases; 
 * the timer will be serviced when the CPU eventually wakes up with a

 * subsequent non-deferrable timer.

 */

#define TBASE_DEFERRABLE_FLAG		(0x1)

#define TIMER_DEFERRABLE		0x1LU



#define TIMER_FLAG_MASK			0x1LU



#define TIMER_INITIALIZER(_function, _expires, _data) {		\

		.entry = { .prev = TIMER_ENTRY_STATIC },	\
@@ -72,7 +74,7 @@ extern struct tvec_base boot_tvec_bases; 
	}



#define TBASE_MAKE_DEFERRED(ptr) ((struct tvec_base *)		\

		  ((unsigned char *)(ptr) + TBASE_DEFERRABLE_FLAG))

		  ((unsigned char *)(ptr) + TIMER_DEFERRABLE))



#define TIMER_DEFERRED_INITIALIZER(_function, _expires, _data) {\

		.entry = { .prev = TIMER_ENTRY_STATIC },	\

kernel/timer.c

+13 −8
Original line number Diff line number Diff line
@@ -92,12 +92,12 @@ static DEFINE_PER_CPU(struct tvec_base *, tvec_bases) = &boot_tvec_bases; 
/* Functions below help us manage 'deferrable' flag */

static inline unsigned int tbase_get_deferrable(struct tvec_base *base)

{

	return ((unsigned int)(unsigned long)base & TBASE_DEFERRABLE_FLAG);

	return ((unsigned int)(unsigned long)base & TIMER_DEFERRABLE);

}



static inline struct tvec_base *tbase_get_base(struct tvec_base *base)

{

	return ((struct tvec_base *)((unsigned long)base & ~TBASE_DEFERRABLE_FLAG));

	return ((struct tvec_base *)((unsigned long)base & ~TIMER_FLAG_MASK));

}



static inline void timer_set_deferrable(struct timer_list *timer)
@@ -108,8 +108,9 @@ static inline void timer_set_deferrable(struct timer_list *timer) 
static inline void

timer_set_base(struct timer_list *timer, struct tvec_base *new_base)

{

	timer->base = (struct tvec_base *)((unsigned long)(new_base) |

				      tbase_get_deferrable(timer->base));

	unsigned long flags = (unsigned long)timer->base & TIMER_FLAG_MASK;



	timer->base = (struct tvec_base *)((unsigned long)(new_base) | flags);

}



static unsigned long round_jiffies_common(unsigned long j, int cpu,
@@ -686,7 +687,7 @@ detach_expired_timer(struct timer_list *timer, struct tvec_base *base) 
{

	detach_timer(timer, true);

	if (!tbase_get_deferrable(timer->base))

		timer->base->active_timers--;

		base->active_timers--;

}



static int detach_if_pending(struct timer_list *timer, struct tvec_base *base,
@@ -697,7 +698,7 @@ static int detach_if_pending(struct timer_list *timer, struct tvec_base *base, 


	detach_timer(timer, clear_pending);

	if (!tbase_get_deferrable(timer->base)) {

		timer->base->active_timers--;

		base->active_timers--;

		if (timer->expires == base->next_timer)

			base->next_timer = base->timer_jiffies;

	}
@@ -1800,9 +1801,13 @@ static struct notifier_block __cpuinitdata timers_nb = { 


void __init init_timers(void)

{

	int err = timer_cpu_notify(&timers_nb, (unsigned long)CPU_UP_PREPARE,

				(void *)(long)smp_processor_id());

	int err;



	/* ensure there are enough low bits for flags in timer->base pointer */

	BUILD_BUG_ON(__alignof__(struct tvec_base) & TIMER_FLAG_MASK);



	err = timer_cpu_notify(&timers_nb, (unsigned long)CPU_UP_PREPARE,

			       (void *)(long)smp_processor_id());

	init_timer_stats();



	BUG_ON(err != NOTIFY_OK);