1 files changed, 348 insertions, 0 deletions
diff --git a/sys/kern/subr_kobj.c b/sys/kern/subr_kobj.c
new file mode 100644
index 0000000..5be746a
--- /dev/null
+++ b/sys/kern/subr_kobj.c
@@ -0,0 +1,348 @@
+/*-
+ * Copyright (c) 2000,2003 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 <sys/param.h>
+#include <sys/kernel.h>
+#include <sys/kobj.h>
+#include <sys/lock.h>
+#include <sys/malloc.h>
+#include <sys/mutex.h>
+#include <sys/sysctl.h>
+#ifndef TEST
+#include <sys/systm.h>
+#endif
+
+#ifdef TEST
+#include "usertest.h"
+#endif
+
+static MALLOC_DEFINE(M_KOBJ, "kobj", "Kernel object structures");
+
+#ifdef KOBJ_STATS
+
+u_int kobj_lookup_hits;
+u_int kobj_lookup_misses;
+
+SYSCTL_UINT(_kern, OID_AUTO, kobj_hits, CTLFLAG_RD,
+	   &kobj_lookup_hits, 0, "");
+SYSCTL_UINT(_kern, OID_AUTO, kobj_misses, CTLFLAG_RD,
+	   &kobj_lookup_misses, 0, "");
+
+#endif
+
+static struct mtx kobj_mtx;
+static int kobj_mutex_inited;
+static int kobj_next_id = 1;
+
+#define	KOBJ_LOCK()		mtx_lock(&kobj_mtx)
+#define	KOBJ_UNLOCK()		mtx_unlock(&kobj_mtx)
+#define	KOBJ_ASSERT(what)	mtx_assert(&kobj_mtx, what);
+
+SYSCTL_INT(_kern, OID_AUTO, kobj_methodcount, CTLFLAG_RD,
+	   &kobj_next_id, 0, "");
+
+static void
+kobj_init_mutex(void *arg)
+{
+	if (!kobj_mutex_inited) {
+		mtx_init(&kobj_mtx, "kobj", NULL, MTX_DEF);
+		kobj_mutex_inited = 1;
+	}
+}
+
+SYSINIT(kobj, SI_SUB_LOCK, SI_ORDER_ANY, kobj_init_mutex, NULL);
+
+/*
+ * This method structure is used to initialise new caches. Since the
+ * desc pointer is NULL, it is guaranteed never to match any read
+ * descriptors.
+ */
+static const struct kobj_method null_method = {
+	0, 0,
+};
+
+int
+kobj_error_method(void)
+{
+
+	return ENXIO;
+}
+
+static void
+kobj_class_compile_common(kobj_class_t cls, kobj_ops_t ops)
+{
+	kobj_method_t *m;
+	int i;
+
+	/*
+	 * Don't do anything if we are already compiled.
+	 */
+	if (cls->ops)
+		return;
+
+	/*
+	 * First register any methods which need it.
+	 */
+	for (i = 0, m = cls->methods; m->desc; i++, m++) {
+		if (m->desc->id == 0)
+			m->desc->id = kobj_next_id++;
+	}
+
+	/*
+	 * Then initialise the ops table.
+	 */
+	for (i = 0; i < KOBJ_CACHE_SIZE; i++)
+		ops->cache[i] = &null_method;
+	ops->cls = cls;
+	cls->ops = ops;
+}
+
+void
+kobj_class_compile(kobj_class_t cls)
+{
+	kobj_ops_t ops;
+
+	KOBJ_ASSERT(MA_NOTOWNED);
+
+	/*
+	 * Allocate space for the compiled ops table.
+	 */
+	ops = malloc(sizeof(struct kobj_ops), M_KOBJ, M_NOWAIT);
+	if (!ops)
+		panic("%s: out of memory", __func__);
+
+	KOBJ_LOCK();
+	
+	/*
+	 * We may have lost a race for kobj_class_compile here - check
+	 * to make sure someone else hasn't already compiled this
+	 * class.
+	 */
+	if (cls->ops) {
+		KOBJ_UNLOCK();
+		free(ops, M_KOBJ);
+		return;
+	}
+
+	kobj_class_compile_common(cls, ops);
+	KOBJ_UNLOCK();
+}
+
+void
+kobj_class_compile_static(kobj_class_t cls, kobj_ops_t ops)
+{
+
+	KASSERT(kobj_mutex_inited == 0,
+	    ("%s: only supported during early cycles", __func__));
+
+	/*
+	 * Increment refs to make sure that the ops table is not freed.
+	 */
+	cls->refs++;
+	kobj_class_compile_common(cls, ops);
+}
+
+static kobj_method_t*
+kobj_lookup_method_class(kobj_class_t cls, kobjop_desc_t desc)
+{
+	kobj_method_t *methods = cls->methods;
+	kobj_method_t *ce;
+
+	for (ce = methods; ce && ce->desc; ce++) {
+		if (ce->desc == desc) {
+			return ce;
+		}
+	}
+
+	return NULL;
+}
+
+static kobj_method_t*
+kobj_lookup_method_mi(kobj_class_t cls,
+		      kobjop_desc_t desc)
+{
+	kobj_method_t *ce;
+	kobj_class_t *basep;
+
+	ce = kobj_lookup_method_class(cls, desc);
+	if (ce)
+		return ce;
+
+	basep = cls->baseclasses;
+	if (basep) {
+		for (; *basep; basep++) {
+			ce = kobj_lookup_method_mi(*basep, desc);
+			if (ce)
+				return ce;
+		}
+	}
+
+	return NULL;
+}
+
+kobj_method_t*
+kobj_lookup_method(kobj_class_t cls,
+		   kobj_method_t **cep,
+		   kobjop_desc_t desc)
+{
+	kobj_method_t *ce;
+
+#ifdef KOBJ_STATS
+	/*
+	 * Correct for the 'hit' assumption in KOBJOPLOOKUP and record
+	 * a 'miss'.
+	 */
+	kobj_lookup_hits--;
+	kobj_lookup_misses++;
+#endif
+
+	ce = kobj_lookup_method_mi(cls, desc);
+	if (!ce)
+		ce = &desc->deflt;
+	*cep = ce;
+	return ce;
+}
+
+void
+kobj_class_free(kobj_class_t cls)
+{
+	void* ops = NULL;
+
+	KOBJ_ASSERT(MA_NOTOWNED);
+	KOBJ_LOCK();
+
+	/*
+	 * Protect against a race between kobj_create and
+	 * kobj_delete.
+	 */
+	if (cls->refs == 0) {
+		/*
+		 * For now we don't do anything to unregister any methods
+		 * which are no longer used.
+		 */
+
+		/*
+		 * Free memory and clean up.
+		 */
+		ops = cls->ops;
+		cls->ops = NULL;
+	}
+	
+	KOBJ_UNLOCK();
+
+	if (ops)
+		free(ops, M_KOBJ);
+}
+
+kobj_t
+kobj_create(kobj_class_t cls,
+	    struct malloc_type *mtype,
+	    int mflags)
+{
+	kobj_t obj;
+
+	/*
+	 * Allocate and initialise the new object.
+	 */
+	obj = malloc(cls->size, mtype, mflags | M_ZERO);
+	if (!obj)
+		return NULL;
+	kobj_init(obj, cls);
+
+	return obj;
+}
+
+static void
+kobj_init_common(kobj_t obj, kobj_class_t cls)
+{
+
+	obj->ops = cls->ops;
+	cls->refs++;
+}
+
+void
+kobj_init(kobj_t obj, kobj_class_t cls)
+{
+	KOBJ_ASSERT(MA_NOTOWNED);
+  retry:
+	KOBJ_LOCK();
+
+	/*
+	 * Consider compiling the class' method table.
+	 */
+	if (!cls->ops) {
+		/*
+		 * kobj_class_compile doesn't want the lock held
+		 * because of the call to malloc - we drop the lock
+		 * and re-try.
+		 */
+		KOBJ_UNLOCK();
+		kobj_class_compile(cls);
+		goto retry;
+	}
+
+	kobj_init_common(obj, cls);
+
+	KOBJ_UNLOCK();
+}
+
+void
+kobj_init_static(kobj_t obj, kobj_class_t cls)
+{
+
+	KASSERT(kobj_mutex_inited == 0,
+	    ("%s: only supported during early cycles", __func__));
+
+	kobj_init_common(obj, cls);
+}
+
+void
+kobj_delete(kobj_t obj, struct malloc_type *mtype)
+{
+	kobj_class_t cls = obj->ops->cls;
+	int refs;
+
+	/*
+	 * Consider freeing the compiled method table for the class
+	 * after its last instance is deleted. As an optimisation, we
+	 * should defer this for a short while to avoid thrashing.
+	 */
+	KOBJ_ASSERT(MA_NOTOWNED);
+	KOBJ_LOCK();
+	cls->refs--;
+	refs = cls->refs;
+	KOBJ_UNLOCK();
+
+	if (!refs)
+		kobj_class_free(cls);
+
+	obj->ops = NULL;
+	if (mtype)
+		free(obj, mtype);
+}