FreeBSD/Linux Kernel Cross Reference
sys/geom/geom_event.c
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
36 /*
37 * XXX: How do we in general know that objects referenced in events
38 * have not been destroyed before we get around to handle the event ?
39 */
40
41 #include <sys/cdefs.h>
42 __FBSDID("$FreeBSD: releng/9.1/sys/geom/geom_event.c 227226 2011-11-06 16:54:23Z mav $");
43
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
82 g_waitidle(void)
83 {
84
85 g_topology_assert_not();
86 mtx_assert(&Giant, MA_NOTOWNED);
87
88 mtx_lock(&g_eventlock);
89 while (!TAILQ_EMPTY(&g_events))
90 msleep(&g_pending_events, &g_eventlock, PPAUSE,
91 "g_waitidle", hz/5);
92 mtx_unlock(&g_eventlock);
93 curthread->td_pflags &= ~TDP_GEOM;
94 }
95
96 #if 0
97 void
98 g_waitidlelock(void)
99 {
100
101 g_topology_assert();
102 mtx_lock(&g_eventlock);
103 while (!TAILQ_EMPTY(&g_events)) {
104 g_topology_unlock();
105 msleep(&g_pending_events, &g_eventlock, PPAUSE,
106 "g_waitidlel", hz/5);
107 g_topology_lock();
108 }
109 mtx_unlock(&g_eventlock);
110 }
111 #endif
112
113 struct g_attrchanged_args {
114 struct g_provider *pp;
115 const char *attr;
116 };
117
118 static void
119 g_attr_changed_event(void *arg, int flag)
120 {
121 struct g_attrchanged_args *args;
122 struct g_provider *pp;
123 struct g_consumer *cp;
124 struct g_consumer *next_cp;
125
126 args = arg;
127 pp = args->pp;
128
129 g_topology_assert();
130 if (flag != EV_CANCEL && g_shutdown == 0) {
131
132 /*
133 * Tell all consumers of the change.
134 */
135 LIST_FOREACH_SAFE(cp, &pp->consumers, consumers, next_cp) {
136 if (cp->geom->attrchanged != NULL)
137 cp->geom->attrchanged(cp, args->attr);
138 }
139 }
140 g_free(args);
141 }
142
143 int
144 g_attr_changed(struct g_provider *pp, const char *attr, int flag)
145 {
146 struct g_attrchanged_args *args;
147 int error;
148
149 args = g_malloc(sizeof *args, flag);
150 if (args == NULL)
151 return (ENOMEM);
152 args->pp = pp;
153 args->attr = attr;
154 error = g_post_event(g_attr_changed_event, args, flag, pp, NULL);
155 if (error != 0)
156 g_free(args);
157 return (error);
158 }
159
160 void
161 g_orphan_provider(struct g_provider *pp, int error)
162 {
163
164 /* G_VALID_PROVIDER(pp) We likely lack topology lock */
165 g_trace(G_T_TOPOLOGY, "g_orphan_provider(%p(%s), %d)",
166 pp, pp->name, error);
167 KASSERT(error != 0,
168 ("g_orphan_provider(%p(%s), 0) error must be non-zero\n",
169 pp, pp->name));
170
171 pp->error = error;
172 mtx_lock(&g_eventlock);
173 KASSERT(!(pp->flags & G_PF_ORPHAN),
174 ("g_orphan_provider(%p(%s)), already an orphan", pp, pp->name));
175 pp->flags |= G_PF_ORPHAN;
176 TAILQ_INSERT_TAIL(&g_doorstep, pp, orphan);
177 mtx_unlock(&g_eventlock);
178 wakeup(&g_wait_event);
179 }
180
181 /*
182 * This function is called once on each provider which the event handler
183 * finds on its g_doorstep.
184 */
185
186 static void
187 g_orphan_register(struct g_provider *pp)
188 {
189 struct g_consumer *cp, *cp2;
190 int wf;
191
192 g_topology_assert();
193 G_VALID_PROVIDER(pp);
194 g_trace(G_T_TOPOLOGY, "g_orphan_register(%s)", pp->name);
195
196 g_cancel_event(pp);
197
198 wf = pp->flags & G_PF_WITHER;
199 pp->flags &= ~G_PF_WITHER;
200
201 /*
202 * Tell all consumers the bad news.
203 * Don't be surprised if they self-destruct.
204 */
205 cp = LIST_FIRST(&pp->consumers);
206 while (cp != NULL) {
207 cp2 = LIST_NEXT(cp, consumers);
208 KASSERT(cp->geom->orphan != NULL,
209 ("geom %s has no orphan, class %s",
210 cp->geom->name, cp->geom->class->name));
211 cp->geom->orphan(cp);
212 cp = cp2;
213 }
214 if (LIST_EMPTY(&pp->consumers) && wf)
215 g_destroy_provider(pp);
216 else
217 pp->flags |= wf;
218 #ifdef notyet
219 cp = LIST_FIRST(&pp->consumers);
220 if (cp != NULL)
221 return;
222 if (pp->geom->flags & G_GEOM_WITHER)
223 g_destroy_provider(pp);
224 #endif
225 }
226
227 static int
228 one_event(void)
229 {
230 struct g_event *ep;
231 struct g_provider *pp;
232
233 g_topology_assert();
234 mtx_lock(&g_eventlock);
235 TAILQ_FOREACH(pp, &g_doorstep, orphan) {
236 if (pp->nstart == pp->nend)
237 break;
238 }
239 if (pp != NULL) {
240 G_VALID_PROVIDER(pp);
241 TAILQ_REMOVE(&g_doorstep, pp, orphan);
242 mtx_unlock(&g_eventlock);
243 g_orphan_register(pp);
244 return (1);
245 }
246
247 ep = TAILQ_FIRST(&g_events);
248 if (ep == NULL) {
249 wakeup(&g_pending_events);
250 return (0);
251 }
252 if (ep->flag & EV_INPROGRESS) {
253 mtx_unlock(&g_eventlock);
254 return (1);
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 TAILQ_REMOVE(&g_events, ep, events);
263 ep->flag &= ~EV_INPROGRESS;
264 if (ep->flag & EV_WAKEUP) {
265 ep->flag |= EV_DONE;
266 mtx_unlock(&g_eventlock);
267 wakeup(ep);
268 } else {
269 mtx_unlock(&g_eventlock);
270 g_free(ep);
271 }
272 return (1);
273 }
274
275 void
276 g_run_events()
277 {
278 int i;
279
280 for (;;) {
281 g_topology_lock();
282 while (one_event())
283 ;
284 mtx_assert(&g_eventlock, MA_OWNED);
285 i = g_wither_work;
286 if (i) {
287 mtx_unlock(&g_eventlock);
288 while (i) {
289 i = g_wither_washer();
290 g_wither_work = i & 1;
291 i &= 2;
292 }
293 g_topology_unlock();
294 } else {
295 g_topology_unlock();
296 msleep(&g_wait_event, &g_eventlock, PRIBIO | PDROP,
297 "-", TAILQ_EMPTY(&g_doorstep) ? 0 : hz / 10);
298 }
299 }
300 /* NOTREACHED */
301 }
302
303 void
304 g_cancel_event(void *ref)
305 {
306 struct g_event *ep, *epn;
307 struct g_provider *pp;
308 u_int n;
309
310 mtx_lock(&g_eventlock);
311 TAILQ_FOREACH(pp, &g_doorstep, orphan) {
312 if (pp != ref)
313 continue;
314 TAILQ_REMOVE(&g_doorstep, pp, orphan);
315 break;
316 }
317 TAILQ_FOREACH_SAFE(ep, &g_events, events, epn) {
318 if (ep->flag & EV_INPROGRESS)
319 continue;
320 for (n = 0; n < G_N_EVENTREFS; n++) {
321 if (ep->ref[n] == NULL)
322 break;
323 if (ep->ref[n] != ref)
324 continue;
325 TAILQ_REMOVE(&g_events, ep, events);
326 ep->func(ep->arg, EV_CANCEL);
327 mtx_assert(&g_eventlock, MA_OWNED);
328 if (ep->flag & EV_WAKEUP) {
329 ep->flag |= (EV_DONE|EV_CANCELED);
330 wakeup(ep);
331 } else {
332 g_free(ep);
333 }
334 break;
335 }
336 }
337 if (TAILQ_EMPTY(&g_events))
338 wakeup(&g_pending_events);
339 mtx_unlock(&g_eventlock);
340 }
341
342 static int
343 g_post_event_x(g_event_t *func, void *arg, int flag, int wuflag, struct g_event **epp, va_list ap)
344 {
345 struct g_event *ep;
346 void *p;
347 u_int n;
348
349 g_trace(G_T_TOPOLOGY, "g_post_event_x(%p, %p, %d, %d)",
350 func, arg, flag, wuflag);
351 KASSERT(wuflag == 0 || wuflag == EV_WAKEUP,
352 ("Wrong wuflag in g_post_event_x(0x%x)", wuflag));
353 ep = g_malloc(sizeof *ep, flag | M_ZERO);
354 if (ep == NULL)
355 return (ENOMEM);
356 ep->flag = wuflag;
357 for (n = 0; n < G_N_EVENTREFS; n++) {
358 p = va_arg(ap, void *);
359 if (p == NULL)
360 break;
361 g_trace(G_T_TOPOLOGY, " ref %p", p);
362 ep->ref[n] = p;
363 }
364 KASSERT(p == NULL, ("Too many references to event"));
365 ep->func = func;
366 ep->arg = arg;
367 mtx_lock(&g_eventlock);
368 TAILQ_INSERT_TAIL(&g_events, ep, events);
369 mtx_unlock(&g_eventlock);
370 wakeup(&g_wait_event);
371 if (epp != NULL)
372 *epp = ep;
373 curthread->td_pflags |= TDP_GEOM;
374 return (0);
375 }
376
377 int
378 g_post_event(g_event_t *func, void *arg, int flag, ...)
379 {
380 va_list ap;
381 int i;
382
383 KASSERT(flag == M_WAITOK || flag == M_NOWAIT,
384 ("Wrong flag to g_post_event"));
385 va_start(ap, flag);
386 i = g_post_event_x(func, arg, flag, 0, NULL, ap);
387 va_end(ap);
388 return (i);
389 }
390
391 void
392 g_do_wither()
393 {
394
395 mtx_lock(&g_eventlock);
396 g_wither_work = 1;
397 mtx_unlock(&g_eventlock);
398 wakeup(&g_wait_event);
399 }
400
401 /*
402 * XXX: It might actually be useful to call this function with topology held.
403 * XXX: This would ensure that the event gets created before anything else
404 * XXX: changes. At present all users have a handle on things in some other
405 * XXX: way, so this remains an XXX for now.
406 */
407
408 int
409 g_waitfor_event(g_event_t *func, void *arg, int flag, ...)
410 {
411 va_list ap;
412 struct g_event *ep;
413 int error;
414
415 g_topology_assert_not();
416 KASSERT(flag == M_WAITOK || flag == M_NOWAIT,
417 ("Wrong flag to g_post_event"));
418 va_start(ap, flag);
419 error = g_post_event_x(func, arg, flag, EV_WAKEUP, &ep, ap);
420 va_end(ap);
421 if (error)
422 return (error);
423
424 mtx_lock(&g_eventlock);
425 while (!(ep->flag & EV_DONE))
426 msleep(ep, &g_eventlock, PRIBIO, "g_waitfor_event", hz);
427 if (ep->flag & EV_CANCELED)
428 error = EAGAIN;
429 mtx_unlock(&g_eventlock);
430
431 g_free(ep);
432 return (error);
433 }
434
435 void
436 g_event_init()
437 {
438
439 mtx_init(&g_eventlock, "GEOM orphanage", NULL, MTX_DEF);
440 }
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