Differential D19565 Diff 57425 sys/compat/linuxkpi/common/src/linux_tasklet.c

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

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#include <linux/compiler.h>		#include <linux/compiler.h>
#include <linux/interrupt.h>		#include <linux/interrupt.h>
#include <linux/compat.h>		#include <linux/compat.h>

#define TASKLET_ST_IDLE 0		#define TASKLET_ST_IDLE 0
#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;
TAILQ_HEAD(, tasklet_struct) head;		TAILQ_HEAD(tasklet_list, tasklet_struct) head;
struct grouptask gtask;		struct grouptask gtask;
} __aligned(CACHE_LINE_SIZE);		} __aligned(CACHE_LINE_SIZE);

#define TASKLET_WORKER_LOCK(tw) mtx_lock(&(tw)->mtx)		#define TASKLET_WORKER_LOCK(tw) mtx_lock(&(tw)->mtx)
#define TASKLET_WORKER_UNLOCK(tw) mtx_unlock(&(tw)->mtx)		#define TASKLET_WORKER_UNLOCK(tw) mtx_unlock(&(tw)->mtx)

DPCPU_DEFINE_STATIC(struct tasklet_worker, tasklet_worker);		DPCPU_DEFINE_STATIC(struct tasklet_worker, tasklet_worker);

static void		static void
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;
		hselaskyUnsubmitted Done Inline Actions struct tasklet_struct ts; struct tasklet_struct last; hselasky: ``` struct tasklet_struct ts; struct tasklet_struct last; ```
		struct tasklet_struct *last;

linux_set_current(curthread);		linux_set_current(curthread);

TASKLET_WORKER_LOCK(tw);		TASKLET_WORKER_LOCK(tw);
		hselaskyUnsubmitted Done Inline Actions last = TAILQ_LAST(&tw->head); hselasky: ``` last = TAILQ_LAST(&tw->head); ```
		last = TAILQ_LAST(&tw->head, tasklet_list);
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);

		if (!atomic_read(&ts->count)) {
TASKLET_WORKER_UNLOCK(tw);		TASKLET_WORKER_UNLOCK(tw);
do {		do {
/* reset executing state */		/* reset executing state */
TASKLET_ST_SET(ts, TASKLET_ST_EXEC);		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);		} while (TASKLET_ST_CMPSET(ts, TASKLET_ST_EXEC,
		TASKLET_ST_IDLE) == 0);
TASKLET_WORKER_LOCK(tw);		TASKLET_WORKER_LOCK(tw);
		} else {
		TAILQ_INSERT_TAIL(&tw->head, ts, entry);
}		}
		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.
		if (ts == last)
		break;
		}
TASKLET_WORKER_UNLOCK(tw);		TASKLET_WORKER_UNLOCK(tw);
}		}

static void		static void
tasklet_subsystem_init(void *arg __unused)		tasklet_subsystem_init(void *arg __unused)
{		{
struct tasklet_worker *tw;		struct tasklet_worker *tw;
char buf[32];		char buf[32];
Show All 35 Lines

void		void
tasklet_init(struct tasklet_struct *ts,		tasklet_init(struct tasklet_struct *ts,
tasklet_func_t *func, unsigned long data)		tasklet_func_t *func, unsigned long data)
{		{
ts->entry.tqe_prev = NULL;		ts->entry.tqe_prev = NULL;
ts->entry.tqe_next = NULL;		ts->entry.tqe_next = NULL;
ts->func = func;		ts->func = func;
ts->data = data;		ts->data = data;
		hselaskyUnsubmitted Done Inline Actions atomic_set(&ts->_state, TASKLET_ST_IDLE); hselasky: atomic_set(&ts->_state, TASKLET_ST_IDLE);
		atomic_set_int(&(ts)->_state, TASKLET_ST_IDLE);
		atomic_set(&ts->count, 0);
}		}

void		void
local_bh_enable(void)		local_bh_enable(void)
{		{
sched_unpin();		sched_unpin();
}		}

void		void
local_bh_disable(void)		local_bh_disable(void)
{		{
sched_pin();		sched_pin();
}		}

void		void
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)) {
struct tasklet_worker *tw;		struct tasklet_worker *tw;

tw = &DPCPU_GET(tasklet_worker);		tw = &DPCPU_GET(tasklet_worker);

/* tasklet_handler() was not queued */		/* tasklet_handler() was not queued */
Show All 27 Lines	tasklet_kill(struct tasklet_struct *ts)
/* wait until tasklet is no longer busy */		/* wait until tasklet is no longer busy */
while (TASKLET_ST_GET(ts) != TASKLET_ST_IDLE)		while (TASKLET_ST_GET(ts) != TASKLET_ST_IDLE)
pause("W", 1);		pause("W", 1);
}		}

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);
		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;		tasklet_unlock_wait(ts);
		hselaskyUnsubmitted Done Inline Actions Ditto. hselasky: Ditto.
if (TASKLET_ST_CMPSET(ts, TASKLET_ST_IDLE, TASKLET_ST_PAUSED))		mb();
break;
pause("W", 1);
}		}

		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);
}		}