3dac505582
classes and if a method is not found in a given class, its base classes are searched (in the order they were declared). This search is recursive, i.e. a method may be define in a base class of a base class. * Change the kobj method lookup algorithm to one which is SMP-safe. This relies only on the constraint that an observer of a sequence of writes of pointer-sized values will see exactly one of those values, not a mixture of two or more values. This assumption holds for all processors which FreeBSD supports. * Add locking to kobj class initialisation. * Add a simpler form of 'inheritance' for devclasses. Each devclass can have a parent devclass. Searches for drivers continue up the chain of devclasses until either a matching driver is found or a devclass is reached which has no parent. This can allow, for instance, pci drivers to match cardbus devices (assuming that cardbus declares pci as its parent devclass). * Increment __FreeBSD_version. This preserves the driver API entirely except for one minor feature used by the ISA compatibility shims. A workaround for ISA compatibility will be committed separately. The kobj and newbus ABI has changed - all modules must be recompiled.
344 lines
6.7 KiB
C
344 lines
6.7 KiB
C
/*-
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* Copyright (c) 2000,2003 Doug Rabson
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#include <sys/kernel.h>
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#include <sys/kobj.h>
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#include <sys/lock.h>
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#include <sys/malloc.h>
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#include <sys/mutex.h>
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#include <sys/sysctl.h>
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#ifndef TEST
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#include <sys/systm.h>
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#endif
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#ifdef TEST
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#include "usertest.h"
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#endif
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static MALLOC_DEFINE(M_KOBJ, "kobj", "Kernel object structures");
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#ifdef KOBJ_STATS
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u_int kobj_lookup_hits;
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u_int kobj_lookup_misses;
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SYSCTL_UINT(_kern, OID_AUTO, kobj_hits, CTLFLAG_RD,
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&kobj_lookup_hits, 0, "");
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SYSCTL_UINT(_kern, OID_AUTO, kobj_misses, CTLFLAG_RD,
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&kobj_lookup_misses, 0, "");
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#endif
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static struct mtx kobj_mtx;
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static int kobj_next_id = 1;
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SYSCTL_UINT(_kern, OID_AUTO, kobj_methodcount, CTLFLAG_RD,
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&kobj_next_id, 0, "");
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static void
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kobj_init_mutex(void *arg)
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{
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mtx_init(&kobj_mtx, "kobj", NULL, MTX_DEF);
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}
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SYSINIT(kobj, SI_SUB_LOCK, SI_ORDER_ANY, kobj_init_mutex, NULL);
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/*
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* This method structure is used to initialise new caches. Since the
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* desc pointer is NULL, it is guaranteed never to match any read
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* descriptors.
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*/
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static struct kobj_method null_method = {
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0, 0,
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};
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int
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kobj_error_method(void)
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{
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return ENXIO;
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}
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static void
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kobj_register_method(struct kobjop_desc *desc)
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{
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mtx_assert(&kobj_mtx, MA_OWNED);
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if (desc->id == 0) {
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desc->id = kobj_next_id++;
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}
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}
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static void
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kobj_unregister_method(struct kobjop_desc *desc)
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{
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}
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static void
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kobj_class_compile_common(kobj_class_t cls, kobj_ops_t ops)
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{
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kobj_method_t *m;
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int i;
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mtx_assert(&kobj_mtx, MA_OWNED);
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/*
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* Don't do anything if we are already compiled.
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*/
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if (cls->ops)
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return;
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/*
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* First register any methods which need it.
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*/
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for (i = 0, m = cls->methods; m->desc; i++, m++)
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kobj_register_method(m->desc);
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/*
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* Then initialise the ops table.
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*/
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for (i = 0; i < KOBJ_CACHE_SIZE; i++)
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ops->cache[i] = &null_method;
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ops->cls = cls;
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cls->ops = ops;
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}
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void
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kobj_class_compile(kobj_class_t cls)
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{
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kobj_ops_t ops;
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mtx_assert(&kobj_mtx, MA_NOTOWNED);
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/*
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* Allocate space for the compiled ops table.
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*/
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ops = malloc(sizeof(struct kobj_ops), M_KOBJ, M_NOWAIT);
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if (!ops)
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panic("kobj_compile_methods: out of memory");
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mtx_lock(&kobj_mtx);
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/*
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* We may have lost a race for kobj_class_compile here - check
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* to make sure someone else hasn't already compiled this
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* class.
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*/
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if (cls->ops) {
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mtx_unlock(&kobj_mtx);
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free(ops, M_KOBJ);
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return;
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}
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kobj_class_compile_common(cls, ops);
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mtx_unlock(&kobj_mtx);
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}
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void
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kobj_class_compile_static(kobj_class_t cls, kobj_ops_t ops)
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{
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mtx_assert(&kobj_mtx, MA_NOTOWNED);
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/*
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* Increment refs to make sure that the ops table is not freed.
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*/
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mtx_lock(&kobj_mtx);
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cls->refs++;
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kobj_class_compile_common(cls, ops);
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mtx_unlock(&kobj_mtx);
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}
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static kobj_method_t*
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kobj_lookup_method_class(kobj_class_t cls, kobjop_desc_t desc)
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{
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kobj_method_t *methods = cls->methods;
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kobj_method_t *ce;
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for (ce = methods; ce && ce->desc; ce++) {
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if (ce->desc == desc) {
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return ce;
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}
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}
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return 0;
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}
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static kobj_method_t*
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kobj_lookup_method_mi(kobj_class_t cls,
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kobjop_desc_t desc)
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{
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kobj_method_t *ce;
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kobj_class_t *basep;
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ce = kobj_lookup_method_class(cls, desc);
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if (ce)
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return ce;
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basep = cls->baseclasses;
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if (basep) {
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for (; *basep; basep++) {
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ce = kobj_lookup_method_mi(*basep, desc);
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if (ce)
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return ce;
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}
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}
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return 0;
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}
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kobj_method_t*
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kobj_lookup_method(kobj_class_t cls,
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kobj_method_t **cep,
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kobjop_desc_t desc)
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{
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kobj_method_t *ce;
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#ifdef KOBJ_STATS
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/*
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* Correct for the 'hit' assumption in KOBJOPLOOKUP and record
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* a 'miss'.
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*/
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kobj_lookup_hits--;
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kobj_lookup_misses--;
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#endif
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ce = kobj_lookup_method_mi(cls, desc);
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if (!ce)
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ce = desc->deflt;
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*cep = ce;
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return ce;
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}
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void
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kobj_class_free(kobj_class_t cls)
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{
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int i;
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kobj_method_t *m;
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void* ops = 0;
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mtx_assert(&kobj_mtx, MA_NOTOWNED);
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mtx_lock(&kobj_mtx);
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/*
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* Protect against a race between kobj_create and
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* kobj_delete.
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*/
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if (cls->refs == 0) {
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/*
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* Unregister any methods which are no longer used.
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*/
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for (i = 0, m = cls->methods; m->desc; i++, m++)
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kobj_unregister_method(m->desc);
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/*
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* Free memory and clean up.
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*/
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ops = cls->ops;
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cls->ops = 0;
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}
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mtx_unlock(&kobj_mtx);
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if (ops)
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free(ops, M_KOBJ);
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}
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kobj_t
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kobj_create(kobj_class_t cls,
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struct malloc_type *mtype,
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int mflags)
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{
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kobj_t obj;
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/*
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* Allocate and initialise the new object.
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*/
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obj = malloc(cls->size, mtype, mflags | M_ZERO);
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if (!obj)
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return 0;
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kobj_init(obj, cls);
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return obj;
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}
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void
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kobj_init(kobj_t obj, kobj_class_t cls)
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{
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mtx_assert(&kobj_mtx, MA_NOTOWNED);
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retry:
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mtx_lock(&kobj_mtx);
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/*
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* Consider compiling the class' method table.
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*/
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if (!cls->ops) {
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/*
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* kobj_class_compile doesn't want the lock held
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* because of the call to malloc - we drop the lock
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* and re-try.
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*/
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mtx_unlock(&kobj_mtx);
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kobj_class_compile(cls);
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goto retry;
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}
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obj->ops = cls->ops;
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cls->refs++;
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mtx_unlock(&kobj_mtx);
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}
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void
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kobj_delete(kobj_t obj, struct malloc_type *mtype)
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{
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kobj_class_t cls = obj->ops->cls;
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int refs;
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/*
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* Consider freeing the compiled method table for the class
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* after its last instance is deleted. As an optimisation, we
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* should defer this for a short while to avoid thrashing.
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*/
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mtx_assert(&kobj_mtx, MA_NOTOWNED);
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mtx_lock(&kobj_mtx);
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cls->refs--;
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refs = cls->refs;
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mtx_unlock(&kobj_mtx);
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if (!refs)
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kobj_class_free(cls);
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obj->ops = 0;
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if (mtype)
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free(obj, mtype);
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}
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