2 * SPDX-License-Identifier: BSD-3-Clause
4 * Copyright (c) 2002 Poul-Henning Kamp
5 * Copyright (c) 2002 Networks Associates Technology, Inc.
8 * This software was developed for the FreeBSD Project by Poul-Henning Kamp
9 * and NAI Labs, the Security Research Division of Network Associates, Inc.
10 * under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the
11 * DARPA CHATS research program.
13 * Redistribution and use in source and binary forms, with or without
14 * modification, are permitted provided that the following conditions
16 * 1. Redistributions of source code must retain the above copyright
17 * notice, this list of conditions and the following disclaimer.
18 * 2. Redistributions in binary form must reproduce the above copyright
19 * notice, this list of conditions and the following disclaimer in the
20 * documentation and/or other materials provided with the distribution.
21 * 3. The names of the authors may not be used to endorse or promote
22 * products derived from this software without specific prior written
25 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
28 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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 ?
43 #include <sys/cdefs.h>
44 __FBSDID("$FreeBSD$");
46 #include <sys/param.h>
47 #include <sys/malloc.h>
48 #include <sys/systm.h>
49 #include <sys/kernel.h>
51 #include <sys/mutex.h>
53 #include <sys/errno.h>
55 #include <geom/geom.h>
56 #include <geom/geom_int.h>
58 #include <machine/stdarg.h>
60 TAILQ_HEAD(event_tailq_head, g_event);
62 static struct event_tailq_head g_events = TAILQ_HEAD_INITIALIZER(g_events);
63 static u_int g_pending_events;
64 static TAILQ_HEAD(,g_provider) g_doorstep = TAILQ_HEAD_INITIALIZER(g_doorstep);
65 static struct mtx g_eventlock;
66 static int g_wither_work;
68 #define G_N_EVENTREFS 20
71 TAILQ_ENTRY(g_event) events;
75 void *ref[G_N_EVENTREFS];
78 #define EV_DONE 0x80000
79 #define EV_WAKEUP 0x40000
80 #define EV_CANCELED 0x20000
81 #define EV_INPROGRESS 0x10000
87 g_topology_assert_not();
89 mtx_lock(&g_eventlock);
90 while (!TAILQ_EMPTY(&g_events))
91 msleep(&g_pending_events, &g_eventlock, PPAUSE,
93 mtx_unlock(&g_eventlock);
94 curthread->td_pflags &= ~TDP_GEOM;
103 mtx_lock(&g_eventlock);
104 while (!TAILQ_EMPTY(&g_events)) {
106 msleep(&g_pending_events, &g_eventlock, PPAUSE,
107 "g_waitidlel", hz/5);
110 mtx_unlock(&g_eventlock);
114 struct g_attrchanged_args {
115 struct g_provider *pp;
120 g_attr_changed_event(void *arg, int flag)
122 struct g_attrchanged_args *args;
123 struct g_provider *pp;
124 struct g_consumer *cp;
125 struct g_consumer *next_cp;
131 if (flag != EV_CANCEL && g_shutdown == 0) {
134 * Tell all consumers of the change.
136 LIST_FOREACH_SAFE(cp, &pp->consumers, consumers, next_cp) {
137 if (cp->geom->attrchanged != NULL)
138 cp->geom->attrchanged(cp, args->attr);
145 g_attr_changed(struct g_provider *pp, const char *attr, int flag)
147 struct g_attrchanged_args *args;
150 args = g_malloc(sizeof *args, flag);
155 error = g_post_event(g_attr_changed_event, args, flag, pp, NULL);
162 g_orphan_provider(struct g_provider *pp, int error)
165 /* G_VALID_PROVIDER(pp) We likely lack topology lock */
166 g_trace(G_T_TOPOLOGY, "g_orphan_provider(%p(%s), %d)",
167 pp, pp->name, error);
169 ("g_orphan_provider(%p(%s), 0) error must be non-zero\n",
173 mtx_lock(&g_eventlock);
174 KASSERT(!(pp->flags & G_PF_ORPHAN),
175 ("g_orphan_provider(%p(%s)), already an orphan", pp, pp->name));
176 pp->flags |= G_PF_ORPHAN;
177 TAILQ_INSERT_TAIL(&g_doorstep, pp, orphan);
178 mtx_unlock(&g_eventlock);
179 wakeup(&g_wait_event);
183 * This function is called once on each provider which the event handler
184 * finds on its g_doorstep.
188 g_orphan_register(struct g_provider *pp)
190 struct g_consumer *cp, *cp2;
194 G_VALID_PROVIDER(pp);
195 g_trace(G_T_TOPOLOGY, "g_orphan_register(%s)", pp->name);
199 wf = pp->flags & G_PF_WITHER;
200 pp->flags &= ~G_PF_WITHER;
203 * Tell all consumers the bad news.
204 * Don't be surprised if they self-destruct.
206 LIST_FOREACH_SAFE(cp, &pp->consumers, consumers, cp2) {
207 KASSERT(cp->geom->orphan != NULL,
208 ("geom %s has no orphan, class %s",
209 cp->geom->name, cp->geom->class->name));
211 * XXX: g_dev_orphan method does deferred destroying
212 * and it is possible, that other event could already
213 * call the orphan method. Check consumer's flags to
214 * do not schedule it twice.
216 if (cp->flags & G_CF_ORPHAN)
218 cp->flags |= G_CF_ORPHAN;
219 cp->geom->orphan(cp);
221 if (LIST_EMPTY(&pp->consumers) && wf)
222 g_destroy_provider(pp);
226 cp = LIST_FIRST(&pp->consumers);
229 if (pp->geom->flags & G_GEOM_WITHER)
230 g_destroy_provider(pp);
238 struct g_provider *pp;
241 mtx_lock(&g_eventlock);
242 TAILQ_FOREACH(pp, &g_doorstep, orphan) {
243 if (pp->nstart == pp->nend)
247 G_VALID_PROVIDER(pp);
248 TAILQ_REMOVE(&g_doorstep, pp, orphan);
249 mtx_unlock(&g_eventlock);
250 g_orphan_register(pp);
254 ep = TAILQ_FIRST(&g_events);
256 wakeup(&g_pending_events);
259 if (ep->flag & EV_INPROGRESS) {
260 mtx_unlock(&g_eventlock);
263 ep->flag |= EV_INPROGRESS;
264 mtx_unlock(&g_eventlock);
266 ep->func(ep->arg, 0);
268 mtx_lock(&g_eventlock);
269 TAILQ_REMOVE(&g_events, ep, events);
270 ep->flag &= ~EV_INPROGRESS;
271 if (ep->flag & EV_WAKEUP) {
273 mtx_unlock(&g_eventlock);
276 mtx_unlock(&g_eventlock);
290 mtx_assert(&g_eventlock, MA_OWNED);
293 mtx_unlock(&g_eventlock);
298 msleep(&g_wait_event, &g_eventlock, PRIBIO | PDROP,
299 "-", TAILQ_EMPTY(&g_doorstep) ? 0 : hz / 10);
306 g_cancel_event(void *ref)
308 struct g_event *ep, *epn;
309 struct g_provider *pp;
312 mtx_lock(&g_eventlock);
313 TAILQ_FOREACH(pp, &g_doorstep, orphan) {
316 TAILQ_REMOVE(&g_doorstep, pp, orphan);
319 TAILQ_FOREACH_SAFE(ep, &g_events, events, epn) {
320 if (ep->flag & EV_INPROGRESS)
322 for (n = 0; n < G_N_EVENTREFS; n++) {
323 if (ep->ref[n] == NULL)
325 if (ep->ref[n] != ref)
327 TAILQ_REMOVE(&g_events, ep, events);
328 ep->func(ep->arg, EV_CANCEL);
329 mtx_assert(&g_eventlock, MA_OWNED);
330 if (ep->flag & EV_WAKEUP) {
331 ep->flag |= (EV_DONE|EV_CANCELED);
339 if (TAILQ_EMPTY(&g_events))
340 wakeup(&g_pending_events);
341 mtx_unlock(&g_eventlock);
345 g_post_event_x(g_event_t *func, void *arg, int flag, int wuflag, struct g_event **epp, va_list ap)
351 g_trace(G_T_TOPOLOGY, "g_post_event_x(%p, %p, %d, %d)",
352 func, arg, flag, wuflag);
353 KASSERT(wuflag == 0 || wuflag == EV_WAKEUP,
354 ("Wrong wuflag in g_post_event_x(0x%x)", wuflag));
355 ep = g_malloc(sizeof *ep, flag | M_ZERO);
359 for (n = 0; n < G_N_EVENTREFS; n++) {
360 p = va_arg(ap, void *);
363 g_trace(G_T_TOPOLOGY, " ref %p", p);
366 KASSERT(p == NULL, ("Too many references to event"));
369 mtx_lock(&g_eventlock);
370 TAILQ_INSERT_TAIL(&g_events, ep, events);
371 mtx_unlock(&g_eventlock);
372 wakeup(&g_wait_event);
375 curthread->td_pflags |= TDP_GEOM;
380 g_post_event(g_event_t *func, void *arg, int flag, ...)
385 KASSERT(flag == M_WAITOK || flag == M_NOWAIT,
386 ("Wrong flag to g_post_event"));
388 i = g_post_event_x(func, arg, flag, 0, NULL, ap);
397 mtx_lock(&g_eventlock);
399 mtx_unlock(&g_eventlock);
400 wakeup(&g_wait_event);
404 * XXX: It might actually be useful to call this function with topology held.
405 * XXX: This would ensure that the event gets created before anything else
406 * XXX: changes. At present all users have a handle on things in some other
407 * XXX: way, so this remains an XXX for now.
411 g_waitfor_event(g_event_t *func, void *arg, int flag, ...)
417 g_topology_assert_not();
418 KASSERT(flag == M_WAITOK || flag == M_NOWAIT,
419 ("Wrong flag to g_post_event"));
421 error = g_post_event_x(func, arg, flag, EV_WAKEUP, &ep, ap);
426 mtx_lock(&g_eventlock);
427 while (!(ep->flag & EV_DONE))
428 msleep(ep, &g_eventlock, PRIBIO, "g_waitfor_event", hz);
429 if (ep->flag & EV_CANCELED)
431 mtx_unlock(&g_eventlock);
441 mtx_init(&g_eventlock, "GEOM orphanage", NULL, MTX_DEF);