Differential D19565 Diff 55166 sys/compat/linuxkpi/common/src/linux_tasklet.c

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sys/compat/linuxkpi/common/src/linux_tasklet.c

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	#define TASKLET_ST_BUSY 1	#define TASKLET_ST_BUSY 1
	#define TASKLET_ST_EXEC 2	#define TASKLET_ST_EXEC 2
	#define TASKLET_ST_LOOP 3	#define TASKLET_ST_LOOP 3
	#define TASKLET_ST_PAUSED 4

	#define TASKLET_ST_CMPSET(ts, old, new) \	#define TASKLET_ST_CMPSET(ts, old, new) \
	atomic_cmpset_ptr((volatile uintptr_t *)&(ts)->entry.tqe_prev, old, new)	atomic_cmpset_int((volatile u_int *)&(ts)->_state, old, new)

	#define TASKLET_ST_SET(ts, new) \	#define TASKLET_ST_SET(ts, new) \
	WRITE_ONCE((volatile uintptr_t )&(ts)->entry.tqe_prev, new)	WRITE_ONCE((volatile u_int )&(ts)->_state, new)

	#define TASKLET_ST_GET(ts) \	#define TASKLET_ST_GET(ts) \
	READ_ONCE((volatile uintptr_t )&(ts)->entry.tqe_prev)	READ_ONCE((volatile u_int )&(ts)->_state)

		#define TASKLET_ST_TESTANDSET(ts, new) \
		atomic_testandset_int((volatile u_int *)&(ts)->_state, new)

	struct tasklet_worker {	struct tasklet_worker {
	struct mtx mtx;	struct mtx mtx;
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	tasklet_handler(void *arg)	tasklet_handler(void *arg)
	{	{
	struct tasklet_worker tw = (struct tasklet_worker )arg;	struct tasklet_worker tw = (struct tasklet_worker )arg;
	struct tasklet_struct *ts;	struct tasklet_struct ts, first;
		hselaskyUnsubmitted Done Inline Actions struct tasklet_struct ts; struct tasklet_struct last; hselasky: ``` struct tasklet_struct ts; struct tasklet_struct last; ```

	linux_set_current(curthread);	linux_set_current(curthread);

	TASKLET_WORKER_LOCK(tw);	TASKLET_WORKER_LOCK(tw);
		first = TAILQ_FIRST(&tw->head);
		hselaskyUnsubmitted Done Inline Actions last = TAILQ_LAST(&tw->head); hselasky: ``` last = TAILQ_LAST(&tw->head); ```
	while (1) {	while (1) {
	ts = TAILQ_FIRST(&tw->head);	ts = TAILQ_FIRST(&tw->head);
	if (ts == NULL)	if (ts == NULL)
	break;	break;
	TAILQ_REMOVE(&tw->head, ts, entry);	TAILQ_REMOVE(&tw->head, ts, entry);

	TASKLET_WORKER_UNLOCK(tw);	if (!atomic_read(&ts->count)) {
	do {	TASKLET_WORKER_UNLOCK(tw);
	/* reset executing state */	do {
	TASKLET_ST_SET(ts, TASKLET_ST_EXEC);	/* reset executing state */
		TASKLET_ST_SET(ts, TASKLET_ST_EXEC);
	ts->func(ts->data);
		ts->func(ts->data);
	} while (TASKLET_ST_CMPSET(ts, TASKLET_ST_EXEC, TASKLET_ST_IDLE) == 0);
	TASKLET_WORKER_LOCK(tw);	} while (TASKLET_ST_CMPSET(ts, TASKLET_ST_EXEC,
		TASKLET_ST_IDLE) == 0);
		TASKLET_WORKER_LOCK(tw);
		} else {
		TAILQ_INSERT_TAIL(&tw->head, ts, entry);
		}
		if (TAILQ_FIRST(&tw->head) == first)
		hselaskyUnsubmitted Done Inline Actions if (ts == last) break; hselasky: ``` if (ts == last) break; ```
		hselaskyUnsubmitted Done Inline Actions Your assumption that TAILQ_FIRST() will always go into the TAILQ_INSERT_TAIL() case does not hold. Please update the code like suggested. hselasky: Your assumption that TAILQ_FIRST() will always go into the TAILQ_INSERT_TAIL() case does not…
		johalunAuthorUnsubmitted Done Inline Actions Oh yes, I see now what you mean. johalun: Oh yes, I see now what you mean.
		break;
	}	}
	TASKLET_WORKER_UNLOCK(tw);	TASKLET_WORKER_UNLOCK(tw);
	}	}
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	ts->entry.tqe_next = NULL;	ts->entry.tqe_next = NULL;
	ts->func = func;	ts->func = func;
	ts->data = data;	ts->data = data;
		ts->_state = TASKLET_ST_IDLE;
		hselaskyUnsubmitted Done Inline Actions atomic_set(&ts->_state, TASKLET_ST_IDLE); hselasky: atomic_set(&ts->_state, TASKLET_ST_IDLE);
		atomic_set(&ts->count, 0);
	}	}

	void	void
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	tasklet_schedule(struct tasklet_struct *ts)	tasklet_schedule(struct tasklet_struct *ts)
	{	{

		/* tasklet is paused */
		if (atomic_read(&ts->count))
		return;

	if (TASKLET_ST_CMPSET(ts, TASKLET_ST_EXEC, TASKLET_ST_LOOP)) {	if (TASKLET_ST_CMPSET(ts, TASKLET_ST_EXEC, TASKLET_ST_LOOP)) {
	/* tasklet_handler() will loop */	/* tasklet_handler() will loop */
	} else if (TASKLET_ST_CMPSET(ts, TASKLET_ST_IDLE, TASKLET_ST_BUSY)) {	} else if (TASKLET_ST_CMPSET(ts, TASKLET_ST_IDLE, TASKLET_ST_BUSY)) {
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	void	void
	tasklet_enable(struct tasklet_struct *ts)	tasklet_enable(struct tasklet_struct *ts)
	{	{
	(void) TASKLET_ST_CMPSET(ts, TASKLET_ST_PAUSED, TASKLET_ST_IDLE);
		barrier();
		hselaskyUnsubmitted Done Inline Actions atomic already has a barrier. I think this one can be removed. hselasky: atomic already has a barrier. I think this one can be removed.
		atomic_dec(&ts->count);
		}

		bool
		tasklet_is_enabled(struct tasklet_struct *ts)
		{

		return !atomic_read(&ts->count);
	}	}

	void	void
	tasklet_disable(struct tasklet_struct *ts)	tasklet_disable(struct tasklet_struct *ts)
	{	{
	while (1) {
	if (TASKLET_ST_GET(ts) == TASKLET_ST_PAUSED)	atomic_inc(&ts->count);
	break;	barrier();
		hselaskyUnsubmitted Done Inline Actions Ditto. hselasky: Ditto.
	if (TASKLET_ST_CMPSET(ts, TASKLET_ST_IDLE, TASKLET_ST_PAUSED))	tasklet_unlock_wait(ts);
	break;	mb();
		}

		int
		tasklet_trylock(struct tasklet_struct *ts)
		{

		return (!TASKLET_ST_TESTANDSET(ts, TASKLET_ST_BUSY));
		}

		void
		tasklet_unlock(struct tasklet_struct *ts)
		{

		TASKLET_ST_SET(ts, TASKLET_ST_IDLE);
		}

		void
		tasklet_unlock_wait(struct tasklet_struct *ts)
		{

		WITNESS_WARN(WARN_GIANTOK \| WARN_SLEEPOK, NULL, "tasklet_kill() can sleep");

		/* wait until tasklet is no longer busy */
		while (TASKLET_ST_GET(ts) != TASKLET_ST_IDLE)
	pause("W", 1);	pause("W", 1);
	}
	}	}
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