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("$FreeBSD$"); 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 LIST_FOREACH_SAFE(cp, &pp->consumers, consumers, cp2) { 206 KASSERT(cp->geom->orphan != NULL, 207 ("geom %s has no orphan, class %s", 208 cp->geom->name, cp->geom->class->name)); 209 /* 210 * XXX: g_dev_orphan method does deferred destroying 211 * and it is possible, that other event could already 212 * call the orphan method. Check consumer's flags to 213 * do not schedule it twice. 214 */ 215 if (cp->flags & G_CF_ORPHAN) 216 continue; 217 cp->flags |= G_CF_ORPHAN; 218 cp->geom->orphan(cp); 219 } 220 if (LIST_EMPTY(&pp->consumers) && wf) 221 g_destroy_provider(pp); 222 else 223 pp->flags |= wf; 224 #ifdef notyet 225 cp = LIST_FIRST(&pp->consumers); 226 if (cp != NULL) 227 return; 228 if (pp->geom->flags & G_GEOM_WITHER) 229 g_destroy_provider(pp); 230 #endif 231 } 232 233 static int 234 one_event(void) 235 { 236 struct g_event *ep; 237 struct g_provider *pp; 238 239 g_topology_assert(); 240 mtx_lock(&g_eventlock); 241 TAILQ_FOREACH(pp, &g_doorstep, orphan) { 242 if (pp->nstart == pp->nend) 243 break; 244 } 245 if (pp != NULL) { 246 G_VALID_PROVIDER(pp); 247 TAILQ_REMOVE(&g_doorstep, pp, orphan); 248 mtx_unlock(&g_eventlock); 249 g_orphan_register(pp); 250 return (1); 251 } 252 253 ep = TAILQ_FIRST(&g_events); 254 if (ep == NULL) { 255 wakeup(&g_pending_events); 256 return (0); 257 } 258 if (ep->flag & EV_INPROGRESS) { 259 mtx_unlock(&g_eventlock); 260 return (1); 261 } 262 ep->flag |= EV_INPROGRESS; 263 mtx_unlock(&g_eventlock); 264 g_topology_assert(); 265 ep->func(ep->arg, 0); 266 g_topology_assert(); 267 mtx_lock(&g_eventlock); 268 TAILQ_REMOVE(&g_events, ep, events); 269 ep->flag &= ~EV_INPROGRESS; 270 if (ep->flag & EV_WAKEUP) { 271 ep->flag |= EV_DONE; 272 mtx_unlock(&g_eventlock); 273 wakeup(ep); 274 } else { 275 mtx_unlock(&g_eventlock); 276 g_free(ep); 277 } 278 return (1); 279 } 280 281 void 282 g_run_events() 283 { 284 285 for (;;) { 286 g_topology_lock(); 287 while (one_event()) 288 ; 289 mtx_assert(&g_eventlock, MA_OWNED); 290 if (g_wither_work) { 291 g_wither_work = 0; 292 mtx_unlock(&g_eventlock); 293 g_wither_washer(); 294 g_topology_unlock(); 295 } else { 296 g_topology_unlock(); 297 msleep(&g_wait_event, &g_eventlock, PRIBIO | PDROP, 298 "-", TAILQ_EMPTY(&g_doorstep) ? 0 : hz / 10); 299 } 300 } 301 /* NOTREACHED */ 302 } 303 304 void 305 g_cancel_event(void *ref) 306 { 307 struct g_event *ep, *epn; 308 struct g_provider *pp; 309 u_int n; 310 311 mtx_lock(&g_eventlock); 312 TAILQ_FOREACH(pp, &g_doorstep, orphan) { 313 if (pp != ref) 314 continue; 315 TAILQ_REMOVE(&g_doorstep, pp, orphan); 316 break; 317 } 318 TAILQ_FOREACH_SAFE(ep, &g_events, events, epn) { 319 if (ep->flag & EV_INPROGRESS) 320 continue; 321 for (n = 0; n < G_N_EVENTREFS; n++) { 322 if (ep->ref[n] == NULL) 323 break; 324 if (ep->ref[n] != ref) 325 continue; 326 TAILQ_REMOVE(&g_events, ep, events); 327 ep->func(ep->arg, EV_CANCEL); 328 mtx_assert(&g_eventlock, MA_OWNED); 329 if (ep->flag & EV_WAKEUP) { 330 ep->flag |= (EV_DONE|EV_CANCELED); 331 wakeup(ep); 332 } else { 333 g_free(ep); 334 } 335 break; 336 } 337 } 338 if (TAILQ_EMPTY(&g_events)) 339 wakeup(&g_pending_events); 340 mtx_unlock(&g_eventlock); 341 } 342 343 static int 344 g_post_event_x(g_event_t *func, void *arg, int flag, int wuflag, struct g_event **epp, va_list ap) 345 { 346 struct g_event *ep; 347 void *p; 348 u_int n; 349 350 g_trace(G_T_TOPOLOGY, "g_post_event_x(%p, %p, %d, %d)", 351 func, arg, flag, wuflag); 352 KASSERT(wuflag == 0 || wuflag == EV_WAKEUP, 353 ("Wrong wuflag in g_post_event_x(0x%x)", wuflag)); 354 ep = g_malloc(sizeof *ep, flag | M_ZERO); 355 if (ep == NULL) 356 return (ENOMEM); 357 ep->flag = wuflag; 358 for (n = 0; n < G_N_EVENTREFS; n++) { 359 p = va_arg(ap, void *); 360 if (p == NULL) 361 break; 362 g_trace(G_T_TOPOLOGY, " ref %p", p); 363 ep->ref[n] = p; 364 } 365 KASSERT(p == NULL, ("Too many references to event")); 366 ep->func = func; 367 ep->arg = arg; 368 mtx_lock(&g_eventlock); 369 TAILQ_INSERT_TAIL(&g_events, ep, events); 370 mtx_unlock(&g_eventlock); 371 wakeup(&g_wait_event); 372 if (epp != NULL) 373 *epp = ep; 374 curthread->td_pflags |= TDP_GEOM; 375 return (0); 376 } 377 378 int 379 g_post_event(g_event_t *func, void *arg, int flag, ...) 380 { 381 va_list ap; 382 int i; 383 384 KASSERT(flag == M_WAITOK || flag == M_NOWAIT, 385 ("Wrong flag to g_post_event")); 386 va_start(ap, flag); 387 i = g_post_event_x(func, arg, flag, 0, NULL, ap); 388 va_end(ap); 389 return (i); 390 } 391 392 void 393 g_do_wither() 394 { 395 396 mtx_lock(&g_eventlock); 397 g_wither_work = 1; 398 mtx_unlock(&g_eventlock); 399 wakeup(&g_wait_event); 400 } 401 402 /* 403 * XXX: It might actually be useful to call this function with topology held. 404 * XXX: This would ensure that the event gets created before anything else 405 * XXX: changes. At present all users have a handle on things in some other 406 * XXX: way, so this remains an XXX for now. 407 */ 408 409 int 410 g_waitfor_event(g_event_t *func, void *arg, int flag, ...) 411 { 412 va_list ap; 413 struct g_event *ep; 414 int error; 415 416 g_topology_assert_not(); 417 KASSERT(flag == M_WAITOK || flag == M_NOWAIT, 418 ("Wrong flag to g_post_event")); 419 va_start(ap, flag); 420 error = g_post_event_x(func, arg, flag, EV_WAKEUP, &ep, ap); 421 va_end(ap); 422 if (error) 423 return (error); 424 425 mtx_lock(&g_eventlock); 426 while (!(ep->flag & EV_DONE)) 427 msleep(ep, &g_eventlock, PRIBIO, "g_waitfor_event", hz); 428 if (ep->flag & EV_CANCELED) 429 error = EAGAIN; 430 mtx_unlock(&g_eventlock); 431 432 g_free(ep); 433 return (error); 434 } 435 436 void 437 g_event_init() 438 { 439 440 mtx_init(&g_eventlock, "GEOM orphanage", NULL, MTX_DEF); 441 } 442