geom_event.c revision 112988 
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 112988 2003-04-02 20:41:18Z 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#include <machine/stdarg.h>
59#endif
60#include <sys/errno.h>
61#include <sys/time.h>
62#include <geom/geom.h>
63#include <geom/geom_int.h>
64
65static struct event_tailq_head g_events = TAILQ_HEAD_INITIALIZER(g_events);
66static u_int g_pending_events;
67static void g_do_event(struct g_event *ep);
68static TAILQ_HEAD(,g_provider) g_doorstep = TAILQ_HEAD_INITIALIZER(g_doorstep);
69static struct mtx g_eventlock;
70static struct sx g_eventstall;
71static int g_shutdown;
72
73void
74g_waitidle(void)
75{
76
77	while (g_pending_events)
78		tsleep(&g_pending_events, PPAUSE, "g_waitidle", hz/5);
79}
80
81void
82g_stall_events(void)
83{
84
85	sx_xlock(&g_eventstall);
86}
87
88void
89g_release_events(void)
90{
91
92	sx_xunlock(&g_eventstall);
93}
94
95void
96g_orphan_provider(struct g_provider *pp, int error)
97{
98
99	g_trace(G_T_TOPOLOGY, "g_orphan_provider(%p(%s), %d)",
100	    pp, pp->name, error);
101	KASSERT(error != 0,
102	    ("g_orphan_provider(%p(%s), 0) error must be non-zero\n",
103	     pp, pp->name));
104	pp->error = error;
105	mtx_lock(&g_eventlock);
106	TAILQ_INSERT_TAIL(&g_doorstep, pp, orphan);
107	mtx_unlock(&g_eventlock);
108	wakeup(&g_wait_event);
109}
110
111/*
112 * This function is called once on each provider which the event handler
113 * finds on its g_doorstep.
114 */
115
116static void
117g_orphan_register(struct g_provider *pp)
118{
119	struct g_consumer *cp, *cp2;
120
121	g_trace(G_T_TOPOLOGY, "g_orphan_register(%s)", pp->name);
122	g_topology_assert();
123
124	/*
125	 * Tell all consumers the bad news.
126	 * Don't be surprised if they self-destruct.
127	 */
128	cp = LIST_FIRST(&pp->consumers);
129	while (cp != NULL) {
130		cp2 = LIST_NEXT(cp, consumers);
131		KASSERT(cp->geom->orphan != NULL,
132		    ("geom %s has no orphan, class %s",
133		    cp->geom->name, cp->geom->class->name));
134		cp->geom->orphan(cp);
135		cp = cp2;
136	}
137#ifdef notyet
138	cp = LIST_FIRST(&pp->consumers);
139	if (cp != NULL)
140		return;
141	if (pp->geom->flags & G_GEOM_WITHER)
142		g_destroy_provider(pp);
143#endif
144}
145
146static void
147g_destroy_event(struct g_event *ep)
148{
149
150	g_free(ep);
151}
152
153static void
154g_do_event(struct g_event *ep)
155{
156	struct g_class *mp, *mp2;
157	struct g_geom *gp;
158	struct g_consumer *cp, *cp2;
159	struct g_provider *pp;
160	int i;
161
162	g_trace(G_T_TOPOLOGY, "g_do_event(%p) %d - ", ep, ep->event);
163	g_topology_assert();
164	switch (ep->event) {
165	case EV_CALL_ME:
166		ep->func(ep->arg, 0);
167		g_topology_assert();
168		break;
169	case EV_NEW_CLASS:
170		if (g_shutdown)
171			break;
172		mp2 = ep->ref[0];
173		if (mp2->taste == NULL)
174			break;
175		LIST_FOREACH(mp, &g_classes, class) {
176			if (mp2 == mp)
177				continue;
178			LIST_FOREACH(gp, &mp->geom, geom) {
179				LIST_FOREACH(pp, &gp->provider, provider) {
180					mp2->taste(mp2, pp, 0);
181					g_topology_assert();
182				}
183			}
184		}
185		break;
186	case EV_NEW_PROVIDER:
187		if (g_shutdown)
188			break;
189		pp = ep->ref[0];
190		g_trace(G_T_TOPOLOGY, "EV_NEW_PROVIDER(%s)", pp->name);
191		LIST_FOREACH(mp, &g_classes, class) {
192			if (mp->taste == NULL)
193				continue;
194			i = 1;
195			LIST_FOREACH(cp, &pp->consumers, consumers)
196				if(cp->geom->class == mp)
197					i = 0;
198			if (i) {
199				mp->taste(mp, pp, 0);
200				g_topology_assert();
201			}
202		}
203		break;
204	case EV_SPOILED:
205		pp = ep->ref[0];
206		g_trace(G_T_TOPOLOGY, "EV_SPOILED(%p(%s),%p)",
207		    pp, pp->name, ep->ref[1]);
208		cp = LIST_FIRST(&pp->consumers);
209		while (cp != NULL) {
210			cp2 = LIST_NEXT(cp, consumers);
211			if (cp->spoiled) {
212				g_trace(G_T_TOPOLOGY, "spoiling %p (%s) (%p)",
213				    cp, cp->geom->name, cp->geom->spoiled);
214				if (cp->geom->spoiled != NULL)
215					cp->geom->spoiled(cp);
216				else
217					cp->spoiled = 0;
218			}
219			cp = cp2;
220		}
221		break;
222	case EV_LAST:
223	default:
224		KASSERT(1 == 0, ("Unknown event %d", ep->event));
225	}
226}
227
228static int
229one_event(void)
230{
231	struct g_event *ep;
232	struct g_provider *pp;
233
234	sx_xlock(&g_eventstall);
235	g_topology_lock();
236	for (;;) {
237		mtx_lock(&g_eventlock);
238		pp = TAILQ_FIRST(&g_doorstep);
239		if (pp != NULL)
240			TAILQ_REMOVE(&g_doorstep, pp, orphan);
241		mtx_unlock(&g_eventlock);
242		if (pp == NULL)
243			break;
244		g_orphan_register(pp);
245	}
246	mtx_lock(&g_eventlock);
247	ep = TAILQ_FIRST(&g_events);
248	if (ep == NULL) {
249		mtx_unlock(&g_eventlock);
250		g_topology_unlock();
251		sx_xunlock(&g_eventstall);
252		return (0);
253	}
254	TAILQ_REMOVE(&g_events, ep, events);
255	mtx_unlock(&g_eventlock);
256	g_do_event(ep);
257	g_destroy_event(ep);
258	g_pending_events--;
259	if (g_pending_events == 0)
260		wakeup(&g_pending_events);
261	g_topology_unlock();
262	sx_xunlock(&g_eventstall);
263	return (1);
264}
265
266void
267g_run_events()
268{
269
270	while (one_event())
271		;
272}
273
274void
275g_post_event(enum g_events ev, ...)
276{
277	struct g_event *ep;
278	va_list ap;
279	void *p;
280	int n;
281
282	g_trace(G_T_TOPOLOGY, "g_post_event(%d)", ev);
283	g_topology_assert();
284	ep = g_malloc(sizeof *ep, M_WAITOK | M_ZERO);
285	ep->event = ev;
286	va_start(ap, ev);
287	for (n = 0; n < G_N_EVENTREFS; n++) {
288		p = va_arg(ap, void *);
289		if (p == NULL)
290			break;
291		g_trace(G_T_TOPOLOGY, "  ref %p", p);
292		ep->ref[n++] = p;
293	}
294	va_end(ap);
295	KASSERT(p == NULL, ("Too many references to event"));
296	mtx_lock(&g_eventlock);
297	g_pending_events++;
298	TAILQ_INSERT_TAIL(&g_events, ep, events);
299	mtx_unlock(&g_eventlock);
300	wakeup(&g_wait_event);
301}
302
303void
304g_cancel_event(void *ref)
305{
306	struct g_event *ep, *epn;
307	u_int n;
308
309	mtx_lock(&g_eventlock);
310	for (ep = TAILQ_FIRST(&g_events); ep != NULL; ep = epn) {
311		epn = TAILQ_NEXT(ep, events);
312		for (n = 0; n < G_N_EVENTREFS; n++) {
313			if (ep->ref[n] == NULL)
314				break;
315			if (ep->ref[n] == ref) {
316				TAILQ_REMOVE(&g_events, ep, events);
317				g_free(ep);
318				break;
319			}
320		}
321	}
322	mtx_unlock(&g_eventlock);
323}
324
325int
326g_call_me(g_call_me_t *func, void *arg, ...)
327{
328	struct g_event *ep;
329	va_list ap;
330	void *p;
331	u_int n;
332
333	g_trace(G_T_TOPOLOGY, "g_call_me(%p, %p", func, arg);
334	ep = g_malloc(sizeof *ep, M_NOWAIT | M_ZERO);
335	if (ep == NULL)
336		return (ENOMEM);
337	va_start(ap, arg);
338	for (n = 0; n < G_N_EVENTREFS; n++) {
339		p = va_arg(ap, void *);
340		if (p == NULL)
341			break;
342		g_trace(G_T_TOPOLOGY, "  ref %p", p);
343		ep->ref[n++] = p;
344	}
345	va_end(ap);
346	KASSERT(p == NULL, ("Too many references to event"));
347	ep->event = EV_CALL_ME;
348	ep->func = func;
349	ep->arg = arg;
350	mtx_lock(&g_eventlock);
351	g_pending_events++;
352	TAILQ_INSERT_TAIL(&g_events, ep, events);
353	mtx_unlock(&g_eventlock);
354	wakeup(&g_wait_event);
355	return (0);
356}
357
358#ifdef _KERNEL
359static void
360geom_shutdown(void *foo __unused)
361{
362
363	g_shutdown = 1;
364}
365#endif
366
367void
368g_event_init()
369{
370
371#ifdef _KERNEL
372
373	EVENTHANDLER_REGISTER(shutdown_pre_sync, geom_shutdown, NULL,
374		SHUTDOWN_PRI_FIRST);
375#endif
376	mtx_init(&g_eventlock, "GEOM orphanage", NULL, MTX_DEF);
377	sx_init(&g_eventstall, "GEOM event stalling");
378}
379