Author: johalun
Date: Thu May 16 18:03:08 2019
New Revision: 347852
URL: https://svnweb.freebsd.org/changeset/base/347852
Log:
LinuxKPI: Updates to tasklets for Linux 5.0.
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
Modified:
head/sys/compat/linuxkpi/common/include/linux/interrupt.h
head/sys/compat/linuxkpi/common/src/linux_tasklet.c
Modified: head/sys/compat/linuxkpi/common/include/linux/interrupt.h
==============================================================================
--- head/sys/compat/linuxkpi/common/include/linux/interrupt.h Thu May 16
18:02:09 2019 (r347851)
+++ head/sys/compat/linuxkpi/common/include/linux/interrupt.h Thu May 16
18:03:08 2019 (r347852)
@@ -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 *, task
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_ */
Modified: head/sys/compat/linuxkpi/common/src/linux_tasklet.c
==============================================================================
--- head/sys/compat/linuxkpi/common/src/linux_tasklet.c Thu May 16 18:02:09
2019 (r347851)
+++ head/sys/compat/linuxkpi/common/src/linux_tasklet.c Thu May 16 18:03:08
2019 (r347852)
@@ -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;
+
+ 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);
- }
}
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