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LinuxKPI: Updates to tasklets for Linux 5.0.

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DRM drivers expect tasklets to have a counter for enable/disable calls.
Also, add a few more tasklet locking functions.

This patch is part of D19565

Reviewed by:	hps
Approved by:	imp (mentor), hps
MFC after:	1 week
This commit is contained in:
Johannes Lundberg 2019-05-16 18:03:08 +00:00
parent 07e0a3ca50
commit 480995dcf0
2 changed files with 66 additions and 21 deletions
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8
sys/compat/linuxkpi/common/include/linux/interrupt.h
View File

@ -189,11 +189,14 @@ typedef void tasklet_func_t(unsigned long);
struct tasklet_struct {
TAILQ_ENTRY(tasklet_struct) entry;
tasklet_func_t *func;
/* Our "state" implementation is different. Avoid same name as Linux. */
volatile u_int tasklet_state;
atomic_t count;
unsigned long data;
};
#define DECLARE_TASKLET(name, func, data) \
struct tasklet_struct name = { { NULL, NULL }, func, data }
struct tasklet_struct name = { { NULL, NULL }, func, ATOMIC_INIT(0), data }
#define tasklet_hi_schedule(t) tasklet_schedule(t)
@ -203,5 +206,8 @@ extern void tasklet_init(struct tasklet_struct *, tasklet_func_t *,
unsigned long data);
extern void tasklet_enable(struct tasklet_struct *);
extern void tasklet_disable(struct tasklet_struct *);
extern int tasklet_trylock(struct tasklet_struct *);
extern void tasklet_unlock(struct tasklet_struct *);
extern void tasklet_unlock_wait(struct tasklet_struct *ts);
#endif /* _LINUX_INTERRUPT_H_ */

79
sys/compat/linuxkpi/common/src/linux_tasklet.c
View File

@ -41,20 +41,22 @@ __FBSDID("$FreeBSD$");
#define TASKLET_ST_BUSY 1
#define TASKLET_ST_EXEC 2
#define TASKLET_ST_LOOP 3
#define TASKLET_ST_PAUSED 4
#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)->tasklet_state, old, new)
#define TASKLET_ST_SET(ts, new) \
WRITE_ONCE(*(volatile uintptr_t *)&(ts)->entry.tqe_prev, new)
WRITE_ONCE(*(volatile u_int *)&(ts)->tasklet_state, new)
#define TASKLET_ST_GET(ts) \
READ_ONCE(*(volatile uintptr_t *)&(ts)->entry.tqe_prev)
READ_ONCE(*(volatile u_int *)&(ts)->tasklet_state)
#define TASKLET_ST_TESTANDSET(ts, new) \
atomic_testandset_int((volatile u_int *)&(ts)->tasklet_state, new)
struct tasklet_worker {
struct mtx mtx;
TAILQ_HEAD(, tasklet_struct) head;
TAILQ_HEAD(tasklet_list, tasklet_struct) head;
struct grouptask gtask;
} __aligned(CACHE_LINE_SIZE);
@ -68,25 +70,34 @@ tasklet_handler(void *arg)
{
struct tasklet_worker *tw = (struct tasklet_worker *)arg;
struct tasklet_struct *ts;
struct tasklet_struct *last;
linux_set_current(curthread);
TASKLET_WORKER_LOCK(tw);
last = TAILQ_LAST(&tw->head, tasklet_list);
while (1) {
ts = TAILQ_FIRST(&tw->head);
if (ts == NULL)
break;
TAILQ_REMOVE(&tw->head, ts, entry);
TASKLET_WORKER_UNLOCK(tw);
do {
/* reset executing state */
TASKLET_ST_SET(ts, TASKLET_ST_EXEC);
if (!atomic_read(&ts->count)) {
TASKLET_WORKER_UNLOCK(tw);
do {
/* 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 (ts == last)
break;
}
TASKLET_WORKER_UNLOCK(tw);
}
@ -140,6 +151,8 @@ tasklet_init(struct tasklet_struct *ts,
ts->entry.tqe_next = NULL;
ts->func = func;
ts->data = data;
atomic_set_int(&ts->tasklet_state, TASKLET_ST_IDLE);
atomic_set(&ts->count, 0);
}
void
@ -158,6 +171,10 @@ void
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)) {
/* tasklet_handler() will loop */
} else if (TASKLET_ST_CMPSET(ts, TASKLET_ST_IDLE, TASKLET_ST_BUSY)) {
@ -201,17 +218,39 @@ tasklet_kill(struct tasklet_struct *ts)
void
tasklet_enable(struct tasklet_struct *ts)
{
(void) TASKLET_ST_CMPSET(ts, TASKLET_ST_PAUSED, TASKLET_ST_IDLE);
atomic_dec(&ts->count);
}
void
tasklet_disable(struct tasklet_struct *ts)
{
while (1) {
if (TASKLET_ST_GET(ts) == TASKLET_ST_PAUSED)
break;
if (TASKLET_ST_CMPSET(ts, TASKLET_ST_IDLE, TASKLET_ST_PAUSED))
break;
pause("W", 1);
}
atomic_inc(&ts->count);
tasklet_unlock_wait(ts);
}
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);
}