TASKQUEUE(9): Use FreeBSD implementation

1 files changed, 509 insertions, 0 deletions

diff --git a/freebsd/sys/kern/subr_taskqueue.c b/freebsd/sys/kern/subr_taskqueue.c
new file mode 100644
index 00000000..bbfe69e4
--- /dev/null
+++ b/freebsd/sys/kern/subr_taskqueue.c
@@ -0,0 +1,509 @@
+#include <machine/rtems-bsd-config.h>
+
+/*-
+ * Copyright (c) 2000 Doug Rabson
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <rtems/bsd/sys/param.h>
+#include <sys/systm.h>
+#include <sys/bus.h>
+#include <sys/interrupt.h>
+#include <sys/kernel.h>
+#include <sys/kthread.h>
+#include <rtems/bsd/sys/lock.h>
+#include <sys/malloc.h>
+#include <sys/mutex.h>
+#include <sys/proc.h>
+#include <sys/sched.h>
+#include <sys/taskqueue.h>
+#include <rtems/bsd/sys/unistd.h>
+#include <machine/stdarg.h>
+
+static MALLOC_DEFINE(M_TASKQUEUE, "taskqueue", "Task Queues");
+#ifndef __rtems__
+static void	*taskqueue_giant_ih;
+#endif /* __rtems__ */
+static void	*taskqueue_ih;
+
+struct taskqueue_busy {
+	struct task	*tb_running;
+	TAILQ_ENTRY(taskqueue_busy) tb_link;
+};
+
+struct taskqueue {
+	STAILQ_HEAD(, task)	tq_queue;
+	const char		*tq_name;
+	taskqueue_enqueue_fn	tq_enqueue;
+	void			*tq_context;
+	TAILQ_HEAD(, taskqueue_busy) tq_active;
+	struct mtx		tq_mutex;
+	struct thread		**tq_threads;
+	int			tq_tcount;
+#ifndef __rtems__
+	int			tq_spin;
+#endif /* __rtems__ */
+	int			tq_flags;
+};
+
+#define	TQ_FLAGS_ACTIVE		(1 << 0)
+#define	TQ_FLAGS_BLOCKED	(1 << 1)
+#define	TQ_FLAGS_PENDING	(1 << 2)
+
+static void	taskqueue_run_locked(struct taskqueue *);
+
+static __inline void
+TQ_LOCK(struct taskqueue *tq)
+{
+#ifndef __rtems__
+	if (tq->tq_spin)
+		mtx_lock_spin(&tq->tq_mutex);
+	else
+#endif /* __rtems__ */
+		mtx_lock(&tq->tq_mutex);
+}
+
+static __inline void
+TQ_UNLOCK(struct taskqueue *tq)
+{
+#ifndef __rtems__
+	if (tq->tq_spin)
+		mtx_unlock_spin(&tq->tq_mutex);
+	else
+#endif /* __rtems__ */
+		mtx_unlock(&tq->tq_mutex);
+}
+
+static __inline int
+TQ_SLEEP(struct taskqueue *tq, void *p, struct mtx *m, int pri, const char *wm,
+    int t)
+{
+#ifndef __rtems__
+	if (tq->tq_spin)
+		return (msleep_spin(p, m, wm, t));
+#endif /* __rtems__ */
+	return (msleep(p, m, pri, wm, t));
+}
+
+static struct taskqueue *
+_taskqueue_create(const char *name, int mflags,
+		 taskqueue_enqueue_fn enqueue, void *context,
+		 int mtxflags, const char *mtxname)
+{
+	struct taskqueue *queue;
+
+	queue = malloc(sizeof(struct taskqueue), M_TASKQUEUE, mflags | M_ZERO);
+	if (!queue)
+		return NULL;
+
+	STAILQ_INIT(&queue->tq_queue);
+	TAILQ_INIT(&queue->tq_active);
+	queue->tq_name = name;
+	queue->tq_enqueue = enqueue;
+	queue->tq_context = context;
+#ifndef __rtems__
+	queue->tq_spin = (mtxflags & MTX_SPIN) != 0;
+#else /* __rtems__ */
+	/*
+	 * FIXME: Here is a potential performance optimization.  Maybe also an
+	 * issue for correctness.
+	 */
+#endif /* __rtems__ */
+	queue->tq_flags |= TQ_FLAGS_ACTIVE;
+	mtx_init(&queue->tq_mutex, mtxname, NULL, mtxflags);
+
+	return queue;
+}
+
+struct taskqueue *
+taskqueue_create(const char *name, int mflags,
+		 taskqueue_enqueue_fn enqueue, void *context)
+{
+	return _taskqueue_create(name, mflags, enqueue, context,
+			MTX_DEF, "taskqueue");
+}
+
+/*
+ * Signal a taskqueue thread to terminate.
+ */
+static void
+taskqueue_terminate(struct thread **pp, struct taskqueue *tq)
+{
+
+	while (tq->tq_tcount > 0) {
+		wakeup(tq);
+		TQ_SLEEP(tq, pp, &tq->tq_mutex, PWAIT, "taskqueue_destroy", 0);
+	}
+}
+
+void
+taskqueue_free(struct taskqueue *queue)
+{
+
+	TQ_LOCK(queue);
+	queue->tq_flags &= ~TQ_FLAGS_ACTIVE;
+	taskqueue_run_locked(queue);
+	taskqueue_terminate(queue->tq_threads, queue);
+	KASSERT(TAILQ_EMPTY(&queue->tq_active), ("Tasks still running?"));
+	mtx_destroy(&queue->tq_mutex);
+	free(queue->tq_threads, M_TASKQUEUE);
+	free(queue, M_TASKQUEUE);
+}
+
+int
+taskqueue_enqueue(struct taskqueue *queue, struct task *task)
+{
+	struct task *ins;
+	struct task *prev;
+
+	TQ_LOCK(queue);
+
+	/*
+	 * Count multiple enqueues.
+	 */
+	if (task->ta_pending) {
+		task->ta_pending++;
+		TQ_UNLOCK(queue);
+		return 0;
+	}
+
+	/*
+	 * Optimise the case when all tasks have the same priority.
+	 */
+	prev = STAILQ_LAST(&queue->tq_queue, task, ta_link);
+	if (!prev || prev->ta_priority >= task->ta_priority) {
+		STAILQ_INSERT_TAIL(&queue->tq_queue, task, ta_link);
+	} else {
+		prev = NULL;
+		for (ins = STAILQ_FIRST(&queue->tq_queue); ins;
+		     prev = ins, ins = STAILQ_NEXT(ins, ta_link))
+			if (ins->ta_priority < task->ta_priority)
+				break;
+
+		if (prev)
+			STAILQ_INSERT_AFTER(&queue->tq_queue, prev, task, ta_link);
+		else
+			STAILQ_INSERT_HEAD(&queue->tq_queue, task, ta_link);
+	}
+
+	task->ta_pending = 1;
+	if ((queue->tq_flags & TQ_FLAGS_BLOCKED) == 0)
+		queue->tq_enqueue(queue->tq_context);
+	else
+		queue->tq_flags |= TQ_FLAGS_PENDING;
+
+	TQ_UNLOCK(queue);
+
+	return 0;
+}
+
+void
+taskqueue_block(struct taskqueue *queue)
+{
+
+	TQ_LOCK(queue);
+	queue->tq_flags |= TQ_FLAGS_BLOCKED;
+	TQ_UNLOCK(queue);
+}
+
+void
+taskqueue_unblock(struct taskqueue *queue)
+{
+
+	TQ_LOCK(queue);
+	queue->tq_flags &= ~TQ_FLAGS_BLOCKED;
+	if (queue->tq_flags & TQ_FLAGS_PENDING) {
+		queue->tq_flags &= ~TQ_FLAGS_PENDING;
+		queue->tq_enqueue(queue->tq_context);
+	}
+	TQ_UNLOCK(queue);
+}
+
+static void
+taskqueue_run_locked(struct taskqueue *queue)
+{
+	struct taskqueue_busy tb;
+	struct task *task;
+	int pending;
+
+	mtx_assert(&queue->tq_mutex, MA_OWNED);
+	tb.tb_running = NULL;
+	TAILQ_INSERT_TAIL(&queue->tq_active, &tb, tb_link);
+
+	while (STAILQ_FIRST(&queue->tq_queue)) {
+		/*
+		 * Carefully remove the first task from the queue and
+		 * zero its pending count.
+		 */
+		task = STAILQ_FIRST(&queue->tq_queue);
+		STAILQ_REMOVE_HEAD(&queue->tq_queue, ta_link);
+		pending = task->ta_pending;
+		task->ta_pending = 0;
+		tb.tb_running = task;
+		TQ_UNLOCK(queue);
+
+		task->ta_func(task->ta_context, pending);
+
+		TQ_LOCK(queue);
+		tb.tb_running = NULL;
+		wakeup(task);
+	}
+	TAILQ_REMOVE(&queue->tq_active, &tb, tb_link);
+}
+
+void
+taskqueue_run(struct taskqueue *queue)
+{
+
+	TQ_LOCK(queue);
+	taskqueue_run_locked(queue);
+	TQ_UNLOCK(queue);
+}
+
+static int
+task_is_running(struct taskqueue *queue, struct task *task)
+{
+	struct taskqueue_busy *tb;
+
+	mtx_assert(&queue->tq_mutex, MA_OWNED);
+	TAILQ_FOREACH(tb, &queue->tq_active, tb_link) {
+		if (tb->tb_running == task)
+			return (1);
+	}
+	return (0);
+}
+
+void
+taskqueue_drain(struct taskqueue *queue, struct task *task)
+{
+#ifndef __rtems__
+	if (queue->tq_spin) {		/* XXX */
+		mtx_lock_spin(&queue->tq_mutex);
+		while (task->ta_pending != 0 || task_is_running(queue, task))
+			msleep_spin(task, &queue->tq_mutex, "-", 0);
+		mtx_unlock_spin(&queue->tq_mutex);
+	} else {
+#endif /* __rtems__ */
+		WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, __func__);
+
+		mtx_lock(&queue->tq_mutex);
+		while (task->ta_pending != 0 || task_is_running(queue, task))
+			msleep(task, &queue->tq_mutex, PWAIT, "-", 0);
+		mtx_unlock(&queue->tq_mutex);
+#ifndef __rtems__
+	}
+#endif /* __rtems__ */
+}
+
+static void
+taskqueue_swi_enqueue(void *context)
+{
+	swi_sched(taskqueue_ih, 0);
+}
+
+static void
+taskqueue_swi_run(void *dummy)
+{
+	taskqueue_run(taskqueue_swi);
+}
+
+#ifndef __rtems__
+static void
+taskqueue_swi_giant_enqueue(void *context)
+{
+	swi_sched(taskqueue_giant_ih, 0);
+}
+
+static void
+taskqueue_swi_giant_run(void *dummy)
+{
+	taskqueue_run(taskqueue_swi_giant);
+}
+#endif /* __rtems__ */
+
+int
+taskqueue_start_threads(struct taskqueue **tqp, int count, int pri,
+			const char *name, ...)
+{
+	va_list ap;
+	struct thread *td;
+	struct taskqueue *tq;
+	int i, error;
+	char ktname[MAXCOMLEN + 1];
+
+	if (count <= 0)
+		return (EINVAL);
+
+	tq = *tqp;
+
+	va_start(ap, name);
+	vsnprintf(ktname, sizeof(ktname), name, ap);
+	va_end(ap);
+
+	tq->tq_threads = malloc(sizeof(struct thread *) * count, M_TASKQUEUE,
+	    M_NOWAIT | M_ZERO);
+	if (tq->tq_threads == NULL) {
+		printf("%s: no memory for %s threads\n", __func__, ktname);
+		return (ENOMEM);
+	}
+
+	for (i = 0; i < count; i++) {
+		if (count == 1)
+			error = kthread_add(taskqueue_thread_loop, tqp, NULL,
+			    &tq->tq_threads[i], RFSTOPPED, 0, "%s", ktname);
+		else
+			error = kthread_add(taskqueue_thread_loop, tqp, NULL,
+			    &tq->tq_threads[i], RFSTOPPED, 0,
+			    "%s_%d", ktname, i);
+		if (error) {
+			/* should be ok to continue, taskqueue_free will dtrt */
+			printf("%s: kthread_add(%s): error %d", __func__,
+			    ktname, error);
+			tq->tq_threads[i] = NULL;		/* paranoid */
+		} else
+			tq->tq_tcount++;
+	}
+#ifndef __rtems__
+	for (i = 0; i < count; i++) {
+		if (tq->tq_threads[i] == NULL)
+			continue;
+		td = tq->tq_threads[i];
+		thread_lock(td);
+		sched_prio(td, pri);
+		sched_add(td, SRQ_BORING);
+		thread_unlock(td);
+	}
+#else /* __rtems__ */
+	(void) td;
+#endif /* __rtems__ */
+
+	return (0);
+}
+
+void
+taskqueue_thread_loop(void *arg)
+{
+	struct taskqueue **tqp, *tq;
+
+	tqp = arg;
+	tq = *tqp;
+	TQ_LOCK(tq);
+	while ((tq->tq_flags & TQ_FLAGS_ACTIVE) != 0) {
+		taskqueue_run_locked(tq);
+		/*
+		 * Because taskqueue_run() can drop tq_mutex, we need to
+		 * check if the TQ_FLAGS_ACTIVE flag wasn't removed in the
+		 * meantime, which means we missed a wakeup.
+		 */
+		if ((tq->tq_flags & TQ_FLAGS_ACTIVE) == 0)
+			break;
+		TQ_SLEEP(tq, tq, &tq->tq_mutex, 0, "-", 0);
+	}
+
+	/* rendezvous with thread that asked us to terminate */
+	tq->tq_tcount--;
+	wakeup_one(tq->tq_threads);
+	TQ_UNLOCK(tq);
+	kthread_exit();
+}
+
+void
+taskqueue_thread_enqueue(void *context)
+{
+	struct taskqueue **tqp, *tq;
+
+	tqp = context;
+	tq = *tqp;
+
+	mtx_assert(&tq->tq_mutex, MA_OWNED);
+	wakeup_one(tq);
+}
+
+TASKQUEUE_DEFINE(swi, taskqueue_swi_enqueue, NULL,
+		 swi_add(NULL, "task queue", taskqueue_swi_run, NULL, SWI_TQ,
+		     INTR_MPSAFE, &taskqueue_ih)); 
+
+#ifndef __rtems__
+TASKQUEUE_DEFINE(swi_giant, taskqueue_swi_giant_enqueue, NULL,
+		 swi_add(NULL, "Giant taskq", taskqueue_swi_giant_run,
+		     NULL, SWI_TQ_GIANT, 0, &taskqueue_giant_ih)); 
+#endif /* __rtems__ */
+
+TASKQUEUE_DEFINE_THREAD(thread);
+
+struct taskqueue *
+taskqueue_create_fast(const char *name, int mflags,
+		 taskqueue_enqueue_fn enqueue, void *context)
+{
+	return _taskqueue_create(name, mflags, enqueue, context,
+			MTX_SPIN, "fast_taskqueue");
+}
+
+/* NB: for backwards compatibility */
+int
+taskqueue_enqueue_fast(struct taskqueue *queue, struct task *task)
+{
+	return taskqueue_enqueue(queue, task);
+}
+
+static void	*taskqueue_fast_ih;
+
+static void
+taskqueue_fast_enqueue(void *context)
+{
+	swi_sched(taskqueue_fast_ih, 0);
+}
+
+static void
+taskqueue_fast_run(void *dummy)
+{
+	taskqueue_run(taskqueue_fast);
+}
+
+TASKQUEUE_FAST_DEFINE(fast, taskqueue_fast_enqueue, NULL,
+	swi_add(NULL, "Fast task queue", taskqueue_fast_run, NULL,
+	SWI_TQ_FAST, INTR_MPSAFE, &taskqueue_fast_ih));
+
+int
+taskqueue_member(struct taskqueue *queue, struct thread *td)
+{
+	int i, j, ret = 0;
+
+	TQ_LOCK(queue);
+	for (i = 0, j = 0; ; i++) {
+		if (queue->tq_threads[i] == NULL)
+			continue;
+		if (queue->tq_threads[i] == td) {
+			ret = 1;
+			break;
+		}
+		if (++j >= queue->tq_tcount)
+			break;
+	}
+	TQ_UNLOCK(queue);
+	return (ret);
+}