1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 2002 Poul-Henning Kamp
5 * Copyright (c) 2002 Networks Associates Technology, Inc.
6 * All rights reserved.
7 *
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.
12 *
13 * Redistribution and use in source and binary forms, with or without
14 * modification, are permitted provided that the following conditions
15 * are met:
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
23 * permission.
24 *
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
35 * SUCH DAMAGE.
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/cdefs.h>
44 #include <sys/param.h>
45 #include <sys/malloc.h>
46 #include <sys/systm.h>
47 #include <sys/kernel.h>
48 #include <sys/lock.h>
49 #include <sys/mutex.h>
50 #include <sys/proc.h>
51 #include <sys/errno.h>
52 #include <sys/time.h>
53 #include <geom/geom.h>
54 #include <geom/geom_int.h>
55
56 #include <machine/stdarg.h>
57
58 TAILQ_HEAD(event_tailq_head, g_event);
59
60 static struct event_tailq_head g_events = TAILQ_HEAD_INITIALIZER(g_events);
61 static u_int g_pending_events;
62 static TAILQ_HEAD(,g_provider) g_doorstep = TAILQ_HEAD_INITIALIZER(g_doorstep);
63 static struct mtx g_eventlock;
64 static int g_wither_work;
65
66 #define G_N_EVENTREFS 20
67
68 struct g_event {
69 TAILQ_ENTRY(g_event) events;
70 g_event_t *func;
71 void *arg;
72 int flag;
73 void *ref[G_N_EVENTREFS];
74 };
75
76 #define EV_DONE 0x80000
77 #define EV_WAKEUP 0x40000
78 #define EV_CANCELED 0x20000
79 #define EV_INPROGRESS 0x10000
80
81 void
g_waitidle(struct thread * td)82 g_waitidle(struct thread *td)
83 {
84
85 g_topology_assert_not();
86
87 mtx_lock(&g_eventlock);
88 TSWAIT("GEOM events");
89 while (!TAILQ_EMPTY(&g_events))
90 msleep(&g_pending_events, &g_eventlock, PPAUSE,
91 "g_waitidle", 0);
92 TSUNWAIT("GEOM events");
93 mtx_unlock(&g_eventlock);
94 td->td_pflags &= ~TDP_GEOM;
95 }
96
97 static void
ast_geom(struct thread * td,int tda __unused)98 ast_geom(struct thread *td, int tda __unused)
99 {
100 /*
101 * If this thread tickled GEOM, we need to wait for the giggling to
102 * stop before we return to userland.
103 */
104 g_waitidle(td);
105 }
106
107 static void
geom_event_init(void * arg __unused)108 geom_event_init(void *arg __unused)
109 {
110 ast_register(TDA_GEOM, ASTR_ASTF_REQUIRED | ASTR_TDP | ASTR_KCLEAR,
111 TDP_GEOM, ast_geom);
112 }
113 SYSINIT(geom_event, SI_SUB_INTRINSIC, SI_ORDER_ANY, geom_event_init, NULL);
114
115 struct g_attrchanged_args {
116 struct g_provider *pp;
117 const char *attr;
118 };
119
120 static void
g_attr_changed_event(void * arg,int flag)121 g_attr_changed_event(void *arg, int flag)
122 {
123 struct g_attrchanged_args *args;
124 struct g_provider *pp;
125 struct g_consumer *cp;
126 struct g_consumer *next_cp;
127
128 args = arg;
129 pp = args->pp;
130
131 g_topology_assert();
132 if (flag != EV_CANCEL && g_shutdown == 0) {
133 /*
134 * Tell all consumers of the change.
135 */
136 LIST_FOREACH_SAFE(cp, &pp->consumers, consumers, next_cp) {
137 if (cp->geom->attrchanged != NULL)
138 cp->geom->attrchanged(cp, args->attr);
139 }
140 }
141 g_free(args);
142 }
143
144 int
g_attr_changed(struct g_provider * pp,const char * attr,int flag)145 g_attr_changed(struct g_provider *pp, const char *attr, int flag)
146 {
147 struct g_attrchanged_args *args;
148 int error;
149
150 args = g_malloc(sizeof *args, flag);
151 if (args == NULL)
152 return (ENOMEM);
153 args->pp = pp;
154 args->attr = attr;
155 error = g_post_event(g_attr_changed_event, args, flag, pp, NULL);
156 if (error != 0)
157 g_free(args);
158 return (error);
159 }
160
161 void
g_orphan_provider(struct g_provider * pp,int error)162 g_orphan_provider(struct g_provider *pp, int error)
163 {
164
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);
168 KASSERT(error != 0,
169 ("g_orphan_provider(%p(%s), 0) error must be non-zero\n",
170 pp, pp->name));
171
172 pp->error = error;
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);
180 }
181
182 /*
183 * This function is called once on each provider which the event handler
184 * finds on its g_doorstep.
185 */
186
187 static void
g_orphan_register(struct g_provider * pp)188 g_orphan_register(struct g_provider *pp)
189 {
190 struct g_consumer *cp, *cp2;
191 int wf;
192
193 g_topology_assert();
194 G_VALID_PROVIDER(pp);
195 g_trace(G_T_TOPOLOGY, "g_orphan_register(%s)", pp->name);
196
197 g_cancel_event(pp);
198
199 wf = pp->flags & G_PF_WITHER;
200 pp->flags &= ~G_PF_WITHER;
201
202 /*
203 * Tell all consumers the bad news.
204 * Don't be surprised if they self-destruct.
205 */
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));
210 /*
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.
215 */
216 if (cp->flags & G_CF_ORPHAN)
217 continue;
218 cp->flags |= G_CF_ORPHAN;
219 cp->geom->orphan(cp);
220 }
221 if (LIST_EMPTY(&pp->consumers) && wf)
222 g_destroy_provider(pp);
223 else
224 pp->flags |= wf;
225 #ifdef notyet
226 cp = LIST_FIRST(&pp->consumers);
227 if (cp != NULL)
228 return;
229 if (pp->geom->flags & G_GEOM_WITHER)
230 g_destroy_provider(pp);
231 #endif
232 }
233
234 static int
one_event(void)235 one_event(void)
236 {
237 struct g_event *ep;
238 struct g_provider *pp;
239
240 g_topology_assert();
241 mtx_lock(&g_eventlock);
242 pp = TAILQ_FIRST(&g_doorstep);
243 if (pp != NULL) {
244 G_VALID_PROVIDER(pp);
245 TAILQ_REMOVE(&g_doorstep, pp, orphan);
246 mtx_unlock(&g_eventlock);
247 g_orphan_register(pp);
248 return (1);
249 }
250
251 ep = TAILQ_FIRST(&g_events);
252 if (ep == NULL) {
253 wakeup(&g_pending_events);
254 return (0);
255 }
256 ep->flag |= EV_INPROGRESS;
257 mtx_unlock(&g_eventlock);
258 g_topology_assert();
259 ep->func(ep->arg, 0);
260 g_topology_assert();
261 mtx_lock(&g_eventlock);
262 TSRELEASE("GEOM events");
263 TAILQ_REMOVE(&g_events, ep, events);
264 ep->flag &= ~EV_INPROGRESS;
265 if (ep->flag & EV_WAKEUP) {
266 ep->flag |= EV_DONE;
267 wakeup(ep);
268 mtx_unlock(&g_eventlock);
269 } else {
270 mtx_unlock(&g_eventlock);
271 g_free(ep);
272 }
273 return (1);
274 }
275
276 void
g_run_events(void)277 g_run_events(void)
278 {
279
280 for (;;) {
281 g_topology_lock();
282 while (one_event())
283 ;
284 mtx_assert(&g_eventlock, MA_OWNED);
285 if (g_wither_work) {
286 g_wither_work = 0;
287 mtx_unlock(&g_eventlock);
288 g_wither_washer();
289 g_topology_unlock();
290 } else {
291 g_topology_unlock();
292 msleep(&g_wait_event, &g_eventlock, PRIBIO | PDROP,
293 "-", 0);
294 }
295 }
296 /* NOTREACHED */
297 }
298
299 void
g_cancel_event(void * ref)300 g_cancel_event(void *ref)
301 {
302 struct g_event *ep, *epn;
303 struct g_provider *pp;
304 u_int n;
305
306 mtx_lock(&g_eventlock);
307 TAILQ_FOREACH(pp, &g_doorstep, orphan) {
308 if (pp != ref)
309 continue;
310 TAILQ_REMOVE(&g_doorstep, pp, orphan);
311 break;
312 }
313 TAILQ_FOREACH_SAFE(ep, &g_events, events, epn) {
314 if (ep->flag & EV_INPROGRESS)
315 continue;
316 for (n = 0; n < G_N_EVENTREFS; n++) {
317 if (ep->ref[n] == NULL)
318 break;
319 if (ep->ref[n] != ref)
320 continue;
321 TSRELEASE("GEOM events");
322 TAILQ_REMOVE(&g_events, ep, events);
323 ep->func(ep->arg, EV_CANCEL);
324 mtx_assert(&g_eventlock, MA_OWNED);
325 if (ep->flag & EV_WAKEUP) {
326 ep->flag |= (EV_DONE|EV_CANCELED);
327 wakeup(ep);
328 } else {
329 g_free(ep);
330 }
331 break;
332 }
333 }
334 if (TAILQ_EMPTY(&g_events))
335 wakeup(&g_pending_events);
336 mtx_unlock(&g_eventlock);
337 }
338
339 struct g_event *
g_alloc_event(int flag)340 g_alloc_event(int flag)
341 {
342 KASSERT(flag == M_WAITOK || flag == M_NOWAIT,
343 ("Wrong flag to g_alloc_event"));
344
345 return (g_malloc(sizeof(struct g_event), flag | M_ZERO));
346 }
347
348 static void
g_post_event_ep_va(g_event_t * func,void * arg,int wuflag,struct g_event * ep,va_list ap)349 g_post_event_ep_va(g_event_t *func, void *arg, int wuflag,
350 struct g_event *ep, va_list ap)
351 {
352 void *p;
353 u_int n;
354
355 ep->flag = wuflag;
356 for (n = 0; n < G_N_EVENTREFS; n++) {
357 p = va_arg(ap, void *);
358 if (p == NULL)
359 break;
360 g_trace(G_T_TOPOLOGY, " ref %p", p);
361 ep->ref[n] = p;
362 }
363 KASSERT(p == NULL, ("Too many references to event"));
364 ep->func = func;
365 ep->arg = arg;
366 mtx_lock(&g_eventlock);
367 TSHOLD("GEOM events");
368 TAILQ_INSERT_TAIL(&g_events, ep, events);
369 mtx_unlock(&g_eventlock);
370 wakeup(&g_wait_event);
371 curthread->td_pflags |= TDP_GEOM;
372 ast_sched(curthread, TDA_GEOM);
373 }
374
375 void
g_post_event_ep(g_event_t * func,void * arg,struct g_event * ep,...)376 g_post_event_ep(g_event_t *func, void *arg, struct g_event *ep, ...)
377 {
378 va_list ap;
379
380 va_start(ap, ep);
381 g_post_event_ep_va(func, arg, 0, ep, ap);
382 va_end(ap);
383 }
384
385
386 static int
g_post_event_x(g_event_t * func,void * arg,int flag,int wuflag,struct g_event ** epp,va_list ap)387 g_post_event_x(g_event_t *func, void *arg, int flag, int wuflag, struct g_event **epp, va_list ap)
388 {
389 struct g_event *ep;
390
391 g_trace(G_T_TOPOLOGY, "g_post_event_x(%p, %p, %d, %d)",
392 func, arg, flag, wuflag);
393 KASSERT(wuflag == 0 || wuflag == EV_WAKEUP,
394 ("Wrong wuflag in g_post_event_x(0x%x)", wuflag));
395 ep = g_alloc_event(flag);
396 if (ep == NULL)
397 return (ENOMEM);
398 if (epp != NULL)
399 *epp = ep;
400 g_post_event_ep_va(func, arg, wuflag, ep, ap);
401 return (0);
402 }
403
404 int
g_post_event(g_event_t * func,void * arg,int flag,...)405 g_post_event(g_event_t *func, void *arg, int flag, ...)
406 {
407 va_list ap;
408 int i;
409
410 KASSERT(flag == M_WAITOK || flag == M_NOWAIT,
411 ("Wrong flag to g_post_event"));
412 va_start(ap, flag);
413 i = g_post_event_x(func, arg, flag, 0, NULL, ap);
414 va_end(ap);
415 return (i);
416 }
417
418 void
g_do_wither(void)419 g_do_wither(void)
420 {
421
422 mtx_lock(&g_eventlock);
423 g_wither_work = 1;
424 mtx_unlock(&g_eventlock);
425 wakeup(&g_wait_event);
426 }
427
428 /*
429 * XXX: It might actually be useful to call this function with topology held.
430 * XXX: This would ensure that the event gets created before anything else
431 * XXX: changes. At present all users have a handle on things in some other
432 * XXX: way, so this remains an XXX for now.
433 */
434
435 int
g_waitfor_event(g_event_t * func,void * arg,int flag,...)436 g_waitfor_event(g_event_t *func, void *arg, int flag, ...)
437 {
438 va_list ap;
439 struct g_event *ep;
440 int error;
441
442 g_topology_assert_not();
443 KASSERT(flag == M_WAITOK || flag == M_NOWAIT,
444 ("Wrong flag to g_post_event"));
445 va_start(ap, flag);
446 error = g_post_event_x(func, arg, flag, EV_WAKEUP, &ep, ap);
447 va_end(ap);
448 if (error)
449 return (error);
450
451 mtx_lock(&g_eventlock);
452 while (!(ep->flag & EV_DONE))
453 msleep(ep, &g_eventlock, PRIBIO, "g_waitfor_event", 0);
454 if (ep->flag & EV_CANCELED)
455 error = EAGAIN;
456 mtx_unlock(&g_eventlock);
457
458 g_free(ep);
459 return (error);
460 }
461
462 void
g_event_init(void)463 g_event_init(void)
464 {
465
466 mtx_init(&g_eventlock, "GEOM orphanage", NULL, MTX_DEF);
467 }
468