geom_event.c revision 112518 
1/*-
2 * Copyright (c) 2002 Poul-Henning Kamp
3 * Copyright (c) 2002 Networks Associates Technology, Inc.
4 * All rights reserved.
5 *
6 * This software was developed for the FreeBSD Project by Poul-Henning Kamp
7 * and NAI Labs, the Security Research Division of Network Associates, Inc.
8 * under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the
9 * DARPA CHATS research program.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 *    notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 *    notice, this list of conditions and the following disclaimer in the
18 *    documentation and/or other materials provided with the distribution.
19 * 3. The names of the authors may not be used to endorse or promote
20 *    products derived from this software without specific prior written
21 *    permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 *
35 * $FreeBSD: head/sys/geom/geom_event.c 112518 2003-03-23 23:01:40Z phk $
36 */
37
38/*
39 * XXX: How do we in general know that objects referenced in events
40 * have not been destroyed before we get around to handle the event ?
41 */
42
43#include <sys/param.h>
44#ifndef _KERNEL
45#include <stdio.h>
46#include <unistd.h>
47#include <string.h>
48#include <stdlib.h>
49#include <signal.h>
50#include <err.h>
51#else
52#include <sys/malloc.h>
53#include <sys/systm.h>
54#include <sys/kernel.h>
55#include <sys/lock.h>
56#include <sys/mutex.h>
57#include <sys/eventhandler.h>
58#endif
59#include <sys/errno.h>
60#include <sys/time.h>
61#include <geom/geom.h>
62#include <geom/geom_int.h>
63
64static struct event_tailq_head g_events = TAILQ_HEAD_INITIALIZER(g_events);
65static u_int g_pending_events;
66static void g_do_event(struct g_event *ep);
67static TAILQ_HEAD(,g_provider) g_doorstep = TAILQ_HEAD_INITIALIZER(g_doorstep);
68static struct mtx g_eventlock;
69static struct sx g_eventstall;
70static int g_shutdown;
71
72void
73g_waitidle(void)
74{
75
76	while (g_pending_events)
77		tsleep(&g_pending_events, PPAUSE, "g_waitidle", hz/5);
78}
79
80void
81g_stall_events(void)
82{
83
84	sx_slock(&g_eventstall);
85}
86
87void
88g_release_events(void)
89{
90
91	sx_sunlock(&g_eventstall);
92}
93
94void
95g_orphan_provider(struct g_provider *pp, int error)
96{
97
98	g_trace(G_T_TOPOLOGY, "g_orphan_provider(%p(%s), %d)",
99	    pp, pp->name, error);
100	KASSERT(error != 0,
101	    ("g_orphan_provider(%p(%s), 0) error must be non-zero\n",
102	     pp, pp->name));
103	pp->error = error;
104	mtx_lock(&g_eventlock);
105	TAILQ_INSERT_TAIL(&g_doorstep, pp, orphan);
106	mtx_unlock(&g_eventlock);
107	wakeup(&g_wait_event);
108}
109
110/*
111 * This function is called once on each provider which the event handler
112 * finds on its g_doorstep.
113 */
114
115static void
116g_orphan_register(struct g_provider *pp)
117{
118	struct g_consumer *cp, *cp2;
119
120	g_trace(G_T_TOPOLOGY, "g_orphan_register(%s)", pp->name);
121	g_topology_assert();
122
123	/*
124	 * Tell all consumers the bad news.
125	 * Don't be surprised if they self-destruct.
126	 */
127	cp = LIST_FIRST(&pp->consumers);
128	while (cp != NULL) {
129		cp2 = LIST_NEXT(cp, consumers);
130		KASSERT(cp->geom->orphan != NULL,
131		    ("geom %s has no orphan, class %s",
132		    cp->geom->name, cp->geom->class->name));
133		cp->geom->orphan(cp);
134		cp = cp2;
135	}
136#ifdef notyet
137	cp = LIST_FIRST(&pp->consumers);
138	if (cp != NULL)
139		return;
140	if (pp->geom->flags & G_GEOM_WITHER)
141		g_destroy_provider(pp);
142#endif
143}
144
145static void
146g_destroy_event(struct g_event *ep)
147{
148
149	g_free(ep);
150}
151
152static void
153g_do_event(struct g_event *ep)
154{
155	struct g_class *mp, *mp2;
156	struct g_geom *gp;
157	struct g_consumer *cp, *cp2;
158	struct g_provider *pp;
159	int i;
160
161	g_trace(G_T_TOPOLOGY, "g_do_event(%p) %d m:%p g:%p p:%p c:%p - ",
162	    ep, ep->event, ep->class, ep->geom, ep->provider, ep->consumer);
163	g_topology_assert();
164	switch (ep->event) {
165	case EV_CALL_ME:
166		ep->func(ep->arg);
167		g_topology_assert();
168		break;
169	case EV_NEW_CLASS:
170		mp2 = ep->class;
171		if (g_shutdown)
172			break;
173		if (mp2->taste == NULL)
174			break;
175		if (g_shutdown)
176			break;
177		LIST_FOREACH(mp, &g_classes, class) {
178			if (mp2 == mp)
179				continue;
180			LIST_FOREACH(gp, &mp->geom, geom) {
181				LIST_FOREACH(pp, &gp->provider, provider) {
182					mp2->taste(ep->class, pp, 0);
183					g_topology_assert();
184				}
185			}
186		}
187		break;
188	case EV_NEW_PROVIDER:
189		if (g_shutdown)
190			break;
191		g_trace(G_T_TOPOLOGY, "EV_NEW_PROVIDER(%s)",
192		    ep->provider->name);
193		LIST_FOREACH(mp, &g_classes, class) {
194			if (mp->taste == NULL)
195				continue;
196			if (!strcmp(ep->provider->name, "geom.ctl") &&
197			    strcmp(mp->name, "DEV"))
198				continue;
199			i = 1;
200			LIST_FOREACH(cp, &ep->provider->consumers, consumers)
201				if(cp->geom->class == mp)
202					i = 0;
203			if (i) {
204				mp->taste(mp, ep->provider, 0);
205				g_topology_assert();
206			}
207		}
208		break;
209	case EV_SPOILED:
210		g_trace(G_T_TOPOLOGY, "EV_SPOILED(%p(%s),%p)",
211		    ep->provider, ep->provider->name, ep->consumer);
212		cp = LIST_FIRST(&ep->provider->consumers);
213		while (cp != NULL) {
214			cp2 = LIST_NEXT(cp, consumers);
215			if (cp->spoiled) {
216				g_trace(G_T_TOPOLOGY, "spoiling %p (%s) (%p)",
217				    cp, cp->geom->name, cp->geom->spoiled);
218				if (cp->geom->spoiled != NULL)
219					cp->geom->spoiled(cp);
220				else
221					cp->spoiled = 0;
222			}
223			cp = cp2;
224		}
225		break;
226	case EV_LAST:
227	default:
228		KASSERT(1 == 0, ("Unknown event %d", ep->event));
229	}
230}
231
232static int
233one_event(void)
234{
235	struct g_event *ep;
236	struct g_provider *pp;
237
238	sx_xlock(&g_eventstall);
239	g_topology_lock();
240	for (;;) {
241		mtx_lock(&g_eventlock);
242		pp = TAILQ_FIRST(&g_doorstep);
243		if (pp != NULL)
244			TAILQ_REMOVE(&g_doorstep, pp, orphan);
245		mtx_unlock(&g_eventlock);
246		if (pp == NULL)
247			break;
248		g_orphan_register(pp);
249	}
250	mtx_lock(&g_eventlock);
251	ep = TAILQ_FIRST(&g_events);
252	if (ep == NULL) {
253		mtx_unlock(&g_eventlock);
254		g_topology_unlock();
255		sx_xunlock(&g_eventstall);
256		return (0);
257	}
258	TAILQ_REMOVE(&g_events, ep, events);
259	mtx_unlock(&g_eventlock);
260	if (ep->class != NULL)
261		ep->class->event = NULL;
262	if (ep->geom != NULL)
263		ep->geom->event = NULL;
264	if (ep->provider != NULL)
265		ep->provider->event = NULL;
266	if (ep->consumer != NULL)
267		ep->consumer->event = NULL;
268	g_do_event(ep);
269	g_destroy_event(ep);
270	g_pending_events--;
271	if (g_pending_events == 0)
272		wakeup(&g_pending_events);
273	g_topology_unlock();
274	sx_xunlock(&g_eventstall);
275	return (1);
276}
277
278void
279g_run_events()
280{
281
282	while (one_event())
283		;
284}
285
286void
287g_post_event(enum g_events ev, struct g_class *mp, struct g_geom *gp, struct g_provider *pp, struct g_consumer *cp)
288{
289	struct g_event *ep;
290
291	g_trace(G_T_TOPOLOGY, "g_post_event(%d, %p, %p, %p, %p)",
292	    ev, mp, gp, pp, cp);
293	g_topology_assert();
294	ep = g_malloc(sizeof *ep, M_WAITOK | M_ZERO);
295	ep->event = ev;
296	if (mp != NULL) {
297		ep->class = mp;
298		KASSERT(mp->event == NULL, ("Double event on class %d %d",
299		    ep->event, mp->event->event));
300		mp->event = ep;
301	}
302	if (gp != NULL) {
303		ep->geom = gp;
304		KASSERT(gp->event == NULL, ("Double event on geom %d %d",
305		    ep->event, gp->event->event));
306		gp->event = ep;
307	}
308	if (pp != NULL) {
309		ep->provider = pp;
310		KASSERT(pp->event == NULL, ("Double event on provider %s %d %d",
311		    pp->name, ep->event, pp->event->event));
312		pp->event = ep;
313	}
314	if (cp != NULL) {
315		ep->consumer = cp;
316		KASSERT(cp->event == NULL, ("Double event on consumer %d %d",
317		    ep->event, cp->event->event));
318		cp->event = ep;
319	}
320	mtx_lock(&g_eventlock);
321	g_pending_events++;
322	TAILQ_INSERT_TAIL(&g_events, ep, events);
323	mtx_unlock(&g_eventlock);
324	wakeup(&g_wait_event);
325}
326
327void
328g_cancel_event(struct g_class *mp, struct g_geom *gp, struct g_provider *pp, struct g_consumer *cp)
329{
330	struct g_event *ep, *epn;
331
332	mtx_lock(&g_eventlock);
333	ep = TAILQ_FIRST(&g_events);
334	for (;ep != NULL;) {
335		epn = TAILQ_NEXT(ep, events);
336		if (
337		    (ep->class != NULL && ep->class == mp) ||
338		    (ep->geom != NULL && ep->geom == gp) ||
339		    (ep->provider != NULL && ep->provider == pp) ||
340		    (ep->consumer != NULL && ep->consumer == cp)) {
341			TAILQ_REMOVE(&g_events, ep, events);
342			g_free(ep);
343		}
344		ep = epn;
345	}
346	mtx_unlock(&g_eventlock);
347}
348
349int
350g_call_me(g_call_me_t *func, void *arg)
351{
352	struct g_event *ep;
353
354	g_trace(G_T_TOPOLOGY, "g_call_me(%p, %p", func, arg);
355	ep = g_malloc(sizeof *ep, M_NOWAIT | M_ZERO);
356	if (ep == NULL)
357		return (ENOMEM);
358	ep->event = EV_CALL_ME;
359	ep->func = func;
360	ep->arg = arg;
361	mtx_lock(&g_eventlock);
362	g_pending_events++;
363	TAILQ_INSERT_TAIL(&g_events, ep, events);
364	mtx_unlock(&g_eventlock);
365	wakeup(&g_wait_event);
366	return (0);
367}
368
369#ifdef _KERNEL
370static void
371geom_shutdown(void *foo __unused)
372{
373
374	g_shutdown = 1;
375}
376#endif
377
378void
379g_event_init()
380{
381
382#ifdef _KERNEL
383
384	EVENTHANDLER_REGISTER(shutdown_pre_sync, geom_shutdown, NULL,
385		SHUTDOWN_PRI_FIRST);
386#endif
387	mtx_init(&g_eventlock, "GEOM orphanage", NULL, MTX_DEF);
388	sx_init(&g_eventstall, "GEOM event stalling");
389}
390