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ALSA: timer: Replace tasklet with work

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The tasklet is an old API that should be deprecated, usually can be
converted to another decent API.  In ALSA core timer API, the
callbacks can be offlined to a tasklet when a flag is set in the timer
backend.  It can be achieved gracefully with a work queued in the
high-prio system workqueue.

This patch replaces the usage of tasklet in ALSA timer API with a
simple work.  Currently the tasklet feature is used only in the system
timer and hrtimer backends, so both are patched to use the new flag
name SNDRV_TIMER_HW_WORK, too.

Link: https://lore.kernel.org/r/20200903104131.21097-3-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Takashi Iwai 2020-09-03 12:41:22 +02:00
parent 68f86a905e
commit bf0835957f
3 changed files with 15 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
include/sound/timer.h
View File

@ -21,13 +21,13 @@
#define SNDRV_TIMER_HW_STOP 0x00000002 /* call stop before start */
#define SNDRV_TIMER_HW_SLAVE 0x00000004 /* only slave timer (variable resolution) */
#define SNDRV_TIMER_HW_FIRST 0x00000008 /* first tick can be incomplete */
#define SNDRV_TIMER_HW_TASKLET 0x00000010 /* timer is called from tasklet */
#define SNDRV_TIMER_HW_WORK 0x00000010 /* timer is called from work */
#define SNDRV_TIMER_IFLG_SLAVE 0x00000001
#define SNDRV_TIMER_IFLG_RUNNING 0x00000002
#define SNDRV_TIMER_IFLG_START 0x00000004
#define SNDRV_TIMER_IFLG_AUTO 0x00000008 /* auto restart */
#define SNDRV_TIMER_IFLG_FAST 0x00000010 /* fast callback (do not use tasklet) */
#define SNDRV_TIMER_IFLG_FAST 0x00000010 /* fast callback (do not use work) */
#define SNDRV_TIMER_IFLG_CALLBACK 0x00000020 /* timer callback is active */
#define SNDRV_TIMER_IFLG_EXCLUSIVE 0x00000040 /* exclusive owner - no more instances */
#define SNDRV_TIMER_IFLG_EARLY_EVENT 0x00000080 /* write early event to the poll queue */
@ -74,7 +74,7 @@ struct snd_timer {
struct list_head active_list_head;
struct list_head ack_list_head;
struct list_head sack_list_head; /* slow ack list head */
struct tasklet_struct task_queue;
struct work_struct task_work;
int max_instances; /* upper limit of timer instances */
int num_instances; /* current number of timer instances */
};
@ -96,7 +96,7 @@ struct snd_timer_instance {
unsigned long ticks; /* auto-load ticks when expired */
unsigned long cticks; /* current ticks */
unsigned long pticks; /* accumulated ticks for callback */
unsigned long resolution; /* current resolution for tasklet */
unsigned long resolution; /* current resolution for work */
unsigned long lost; /* lost ticks */
int slave_class;
unsigned int slave_id;

2
sound/core/hrtimer.c
View File

@ -114,7 +114,7 @@ static int snd_hrtimer_stop(struct snd_timer *t)
}
static const struct snd_timer_hardware hrtimer_hw __initconst = {
.flags = SNDRV_TIMER_HW_AUTO | SNDRV_TIMER_HW_TASKLET,
.flags = SNDRV_TIMER_HW_AUTO | SNDRV_TIMER_HW_WORK,
.open = snd_hrtimer_open,
.close = snd_hrtimer_close,
.start = snd_hrtimer_start,

20
sound/core/timer.c
View File

@ -813,12 +813,12 @@ static void snd_timer_clear_callbacks(struct snd_timer *timer,
}
/*
* timer tasklet
* timer work
*
*/
static void snd_timer_tasklet(struct tasklet_struct *t)
static void snd_timer_work(struct work_struct *work)
{
struct snd_timer *timer = from_tasklet(timer, t, task_queue);
struct snd_timer *timer = container_of(work, struct snd_timer, task_work);
unsigned long flags;
if (timer->card && timer->card->shutdown) {
@ -843,7 +843,7 @@ void snd_timer_interrupt(struct snd_timer * timer, unsigned long ticks_left)
unsigned long resolution;
struct list_head *ack_list_head;
unsigned long flags;
int use_tasklet = 0;
bool use_work = false;
if (timer == NULL)
return;
@ -884,7 +884,7 @@ void snd_timer_interrupt(struct snd_timer * timer, unsigned long ticks_left)
--timer->running;
list_del_init(&ti->active_list);
}
if ((timer->hw.flags & SNDRV_TIMER_HW_TASKLET) ||
if ((timer->hw.flags & SNDRV_TIMER_HW_WORK) ||
(ti->flags & SNDRV_TIMER_IFLG_FAST))
ack_list_head = &timer->ack_list_head;
else
@ -919,11 +919,11 @@ void snd_timer_interrupt(struct snd_timer * timer, unsigned long ticks_left)
snd_timer_process_callbacks(timer, &timer->ack_list_head);
/* do we have any slow callbacks? */
use_tasklet = !list_empty(&timer->sack_list_head);
use_work = !list_empty(&timer->sack_list_head);
spin_unlock_irqrestore(&timer->lock, flags);
if (use_tasklet)
tasklet_schedule(&timer->task_queue);
if (use_work)
queue_work(system_highpri_wq, &timer->task_work);
}
EXPORT_SYMBOL(snd_timer_interrupt);
@ -967,7 +967,7 @@ int snd_timer_new(struct snd_card *card, char *id, struct snd_timer_id *tid,
INIT_LIST_HEAD(&timer->ack_list_head);
INIT_LIST_HEAD(&timer->sack_list_head);
spin_lock_init(&timer->lock);
tasklet_setup(&timer->task_queue, snd_timer_tasklet);
INIT_WORK(&timer->task_work, snd_timer_work);
timer->max_instances = 1000; /* default limit per timer */
if (card != NULL) {
timer->module = card->module;
@ -1200,7 +1200,7 @@ static int snd_timer_s_close(struct snd_timer *timer)
static const struct snd_timer_hardware snd_timer_system =
{
.flags = SNDRV_TIMER_HW_FIRST | SNDRV_TIMER_HW_TASKLET,
.flags = SNDRV_TIMER_HW_FIRST | SNDRV_TIMER_HW_WORK,
.resolution = 1000000000L / HZ,
.ticks = 10000000L,
.close = snd_timer_s_close,