Please welcome ZFS - The last word in file systems.

ZFS file system was ported from OpenSolaris operating system. The code in under
CDDL license.

I'd like to thank all SUN developers that created this great piece of software.

Supported by:	Wheel LTD (http://www.wheel.pl/)
Supported by:	The FreeBSD Foundation (http://www.freebsdfoundation.org/)
Supported by:	Sentex (http://www.sentex.net/)

1 files changed, 250 insertions, 0 deletions

diff --git a/cddl/contrib/opensolaris/lib/libzpool/common/taskq.c b/cddl/contrib/opensolaris/lib/libzpool/common/taskq.c
new file mode 100644
index 0000000..f7b6571
--- /dev/null
+++ b/cddl/contrib/opensolaris/lib/libzpool/common/taskq.c
@@ -0,0 +1,250 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License, Version 1.0 only
+ * (the "License").  You may not use this file except in compliance
+ * with the License.
+ *
+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+ * or http://www.opensolaris.org/os/licensing.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+/*
+ * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
+ * Use is subject to license terms.
+ */
+
+#pragma ident	"%Z%%M%	%I%	%E% SMI"
+
+#include <sys/zfs_context.h>
+
+int taskq_now;
+
+typedef struct task {
+	struct task	*task_next;
+	struct task	*task_prev;
+	task_func_t	*task_func;
+	void		*task_arg;
+} task_t;
+
+#define	TASKQ_ACTIVE	0x00010000
+
+struct taskq {
+	kmutex_t	tq_lock;
+	krwlock_t	tq_threadlock;
+	kcondvar_t	tq_dispatch_cv;
+	kcondvar_t	tq_wait_cv;
+	thread_t	*tq_threadlist;
+	int		tq_flags;
+	int		tq_active;
+	int		tq_nthreads;
+	int		tq_nalloc;
+	int		tq_minalloc;
+	int		tq_maxalloc;
+	task_t		*tq_freelist;
+	task_t		tq_task;
+};
+
+static task_t *
+task_alloc(taskq_t *tq, int tqflags)
+{
+	task_t *t;
+
+	if ((t = tq->tq_freelist) != NULL && tq->tq_nalloc >= tq->tq_minalloc) {
+		tq->tq_freelist = t->task_next;
+	} else {
+		mutex_exit(&tq->tq_lock);
+		if (tq->tq_nalloc >= tq->tq_maxalloc) {
+			if (!(tqflags & KM_SLEEP)) {
+				mutex_enter(&tq->tq_lock);
+				return (NULL);
+			}
+			/*
+			 * We don't want to exceed tq_maxalloc, but we can't
+			 * wait for other tasks to complete (and thus free up
+			 * task structures) without risking deadlock with
+			 * the caller.  So, we just delay for one second
+			 * to throttle the allocation rate.
+			 */
+			delay(hz);
+		}
+		t = kmem_alloc(sizeof (task_t), tqflags);
+		mutex_enter(&tq->tq_lock);
+		if (t != NULL)
+			tq->tq_nalloc++;
+	}
+	return (t);
+}
+
+static void
+task_free(taskq_t *tq, task_t *t)
+{
+	if (tq->tq_nalloc <= tq->tq_minalloc) {
+		t->task_next = tq->tq_freelist;
+		tq->tq_freelist = t;
+	} else {
+		tq->tq_nalloc--;
+		mutex_exit(&tq->tq_lock);
+		kmem_free(t, sizeof (task_t));
+		mutex_enter(&tq->tq_lock);
+	}
+}
+
+taskqid_t
+taskq_dispatch(taskq_t *tq, task_func_t func, void *arg, uint_t tqflags)
+{
+	task_t *t;
+
+	if (taskq_now) {
+		func(arg);
+		return (1);
+	}
+
+	mutex_enter(&tq->tq_lock);
+	ASSERT(tq->tq_flags & TASKQ_ACTIVE);
+	if ((t = task_alloc(tq, tqflags)) == NULL) {
+		mutex_exit(&tq->tq_lock);
+		return (0);
+	}
+	t->task_next = &tq->tq_task;
+	t->task_prev = tq->tq_task.task_prev;
+	t->task_next->task_prev = t;
+	t->task_prev->task_next = t;
+	t->task_func = func;
+	t->task_arg = arg;
+	cv_signal(&tq->tq_dispatch_cv);
+	mutex_exit(&tq->tq_lock);
+	return (1);
+}
+
+void
+taskq_wait(taskq_t *tq)
+{
+	mutex_enter(&tq->tq_lock);
+	while (tq->tq_task.task_next != &tq->tq_task || tq->tq_active != 0)
+		cv_wait(&tq->tq_wait_cv, &tq->tq_lock);
+	mutex_exit(&tq->tq_lock);
+}
+
+static void *
+taskq_thread(void *arg)
+{
+	taskq_t *tq = arg;
+	task_t *t;
+
+	mutex_enter(&tq->tq_lock);
+	while (tq->tq_flags & TASKQ_ACTIVE) {
+		if ((t = tq->tq_task.task_next) == &tq->tq_task) {
+			if (--tq->tq_active == 0)
+				cv_broadcast(&tq->tq_wait_cv);
+			cv_wait(&tq->tq_dispatch_cv, &tq->tq_lock);
+			tq->tq_active++;
+			continue;
+		}
+		t->task_prev->task_next = t->task_next;
+		t->task_next->task_prev = t->task_prev;
+		mutex_exit(&tq->tq_lock);
+
+		rw_enter(&tq->tq_threadlock, RW_READER);
+		t->task_func(t->task_arg);
+		rw_exit(&tq->tq_threadlock);
+
+		mutex_enter(&tq->tq_lock);
+		task_free(tq, t);
+	}
+	tq->tq_nthreads--;
+	cv_broadcast(&tq->tq_wait_cv);
+	mutex_exit(&tq->tq_lock);
+	return (NULL);
+}
+
+/*ARGSUSED*/
+taskq_t *
+taskq_create(const char *name, int nthreads, pri_t pri,
+	int minalloc, int maxalloc, uint_t flags)
+{
+	taskq_t *tq = kmem_zalloc(sizeof (taskq_t), KM_SLEEP);
+	int t;
+
+	rw_init(&tq->tq_threadlock, NULL, RW_DEFAULT, NULL);
+	tq->tq_flags = flags | TASKQ_ACTIVE;
+	tq->tq_active = nthreads;
+	tq->tq_nthreads = nthreads;
+	tq->tq_minalloc = minalloc;
+	tq->tq_maxalloc = maxalloc;
+	tq->tq_task.task_next = &tq->tq_task;
+	tq->tq_task.task_prev = &tq->tq_task;
+	tq->tq_threadlist = kmem_alloc(nthreads * sizeof (thread_t), KM_SLEEP);
+
+	if (flags & TASKQ_PREPOPULATE) {
+		mutex_enter(&tq->tq_lock);
+		while (minalloc-- > 0)
+			task_free(tq, task_alloc(tq, KM_SLEEP));
+		mutex_exit(&tq->tq_lock);
+	}
+
+	for (t = 0; t < nthreads; t++)
+		(void) thr_create(0, 0, taskq_thread,
+		    tq, THR_BOUND, &tq->tq_threadlist[t]);
+
+	return (tq);
+}
+
+void
+taskq_destroy(taskq_t *tq)
+{
+	int t;
+	int nthreads = tq->tq_nthreads;
+
+	taskq_wait(tq);
+
+	mutex_enter(&tq->tq_lock);
+
+	tq->tq_flags &= ~TASKQ_ACTIVE;
+	cv_broadcast(&tq->tq_dispatch_cv);
+
+	while (tq->tq_nthreads != 0)
+		cv_wait(&tq->tq_wait_cv, &tq->tq_lock);
+
+	tq->tq_minalloc = 0;
+	while (tq->tq_nalloc != 0) {
+		ASSERT(tq->tq_freelist != NULL);
+		task_free(tq, task_alloc(tq, KM_SLEEP));
+	}
+
+	mutex_exit(&tq->tq_lock);
+
+	for (t = 0; t < nthreads; t++)
+		(void) thr_join(tq->tq_threadlist[t], NULL, NULL);
+
+	kmem_free(tq->tq_threadlist, nthreads * sizeof (thread_t));
+
+	rw_destroy(&tq->tq_threadlock);
+
+	kmem_free(tq, sizeof (taskq_t));
+}
+
+int
+taskq_member(taskq_t *tq, void *t)
+{
+	int i;
+
+	if (taskq_now)
+		return (1);
+
+	for (i = 0; i < tq->tq_nthreads; i++)
+		if (tq->tq_threadlist[i] == (thread_t)(uintptr_t)t)
+			return (1);
+
+	return (0);
+}