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 87 mtx_lock(&g_eventlock); 88 while (!TAILQ_EMPTY(&g_events)) 89 msleep(&g_pending_events, &g_eventlock, PPAUSE, 90 "g_waitidle", hz/5); 91 mtx_unlock(&g_eventlock); 92 curthread->td_pflags &= ~TDP_GEOM; 93 } 94 95 #if 0 96 void 97 g_waitidlelock(void) 98 { 99 100 g_topology_assert(); 101 mtx_lock(&g_eventlock); 102 while (!TAILQ_EMPTY(&g_events)) { 103 g_topology_unlock(); 104 msleep(&g_pending_events, &g_eventlock, PPAUSE, 105 "g_waitidlel", hz/5); 106 g_topology_lock(); 107 } 108 mtx_unlock(&g_eventlock); 109 } 110 #endif 111 112 struct g_attrchanged_args { 113 struct g_provider *pp; 114 const char *attr; 115 }; 116 117 static void 118 g_attr_changed_event(void *arg, int flag) 119 { 120 struct g_attrchanged_args *args; 121 struct g_provider *pp; 122 struct g_consumer *cp; 123 struct g_consumer *next_cp; 124 125 args = arg; 126 pp = args->pp; 127 128 g_topology_assert(); 129 if (flag != EV_CANCEL && g_shutdown == 0) { 130 131 /* 132 * Tell all consumers of the change. 133 */ 134 LIST_FOREACH_SAFE(cp, &pp->consumers, consumers, next_cp) { 135 if (cp->geom->attrchanged != NULL) 136 cp->geom->attrchanged(cp, args->attr); 137 } 138 } 139 g_free(args); 140 } 141 142 int 143 g_attr_changed(struct g_provider *pp, const char *attr, int flag) 144 { 145 struct g_attrchanged_args *args; 146 int error; 147 148 args = g_malloc(sizeof *args, flag); 149 if (args == NULL) 150 return (ENOMEM); 151 args->pp = pp; 152 args->attr = attr; 153 error = g_post_event(g_attr_changed_event, args, flag, pp, NULL); 154 if (error != 0) 155 g_free(args); 156 return (error); 157 } 158 159 void 160 g_orphan_provider(struct g_provider *pp, int error) 161 { 162 163 /* G_VALID_PROVIDER(pp) We likely lack topology lock */ 164 g_trace(G_T_TOPOLOGY, "g_orphan_provider(%p(%s), %d)", 165 pp, pp->name, error); 166 KASSERT(error != 0, 167 ("g_orphan_provider(%p(%s), 0) error must be non-zero\n", 168 pp, pp->name)); 169 170 pp->error = error; 171 mtx_lock(&g_eventlock); 172 KASSERT(!(pp->flags & G_PF_ORPHAN), 173 ("g_orphan_provider(%p(%s)), already an orphan", pp, pp->name)); 174 pp->flags |= G_PF_ORPHAN; 175 TAILQ_INSERT_TAIL(&g_doorstep, pp, orphan); 176 mtx_unlock(&g_eventlock); 177 wakeup(&g_wait_event); 178 } 179 180 /* 181 * This function is called once on each provider which the event handler 182 * finds on its g_doorstep. 183 */ 184 185 static void 186 g_orphan_register(struct g_provider *pp) 187 { 188 struct g_consumer *cp, *cp2; 189 int wf; 190 191 g_topology_assert(); 192 G_VALID_PROVIDER(pp); 193 g_trace(G_T_TOPOLOGY, "g_orphan_register(%s)", pp->name); 194 195 g_cancel_event(pp); 196 197 wf = pp->flags & G_PF_WITHER; 198 pp->flags &= ~G_PF_WITHER; 199 200 /* 201 * Tell all consumers the bad news. 202 * Don't be surprised if they self-destruct. 203 */ 204 LIST_FOREACH_SAFE(cp, &pp->consumers, consumers, cp2) { 205 KASSERT(cp->geom->orphan != NULL, 206 ("geom %s has no orphan, class %s", 207 cp->geom->name, cp->geom->class->name)); 208 /* 209 * XXX: g_dev_orphan method does deferred destroying 210 * and it is possible, that other event could already 211 * call the orphan method. Check consumer's flags to 212 * do not schedule it twice. 213 */ 214 if (cp->flags & G_CF_ORPHAN) 215 continue; 216 cp->flags |= G_CF_ORPHAN; 217 cp->geom->orphan(cp); 218 } 219 if (LIST_EMPTY(&pp->consumers) && wf) 220 g_destroy_provider(pp); 221 else 222 pp->flags |= wf; 223 #ifdef notyet 224 cp = LIST_FIRST(&pp->consumers); 225 if (cp != NULL) 226 return; 227 if (pp->geom->flags & G_GEOM_WITHER) 228 g_destroy_provider(pp); 229 #endif 230 } 231 232 static int 233 one_event(void) 234 { 235 struct g_event *ep; 236 struct g_provider *pp; 237 238 g_topology_assert(); 239 mtx_lock(&g_eventlock); 240 TAILQ_FOREACH(pp, &g_doorstep, orphan) { 241 if (pp->nstart == pp->nend) 242 break; 243 } 244 if (pp != NULL) { 245 G_VALID_PROVIDER(pp); 246 TAILQ_REMOVE(&g_doorstep, pp, orphan); 247 mtx_unlock(&g_eventlock); 248 g_orphan_register(pp); 249 return (1); 250 } 251 252 ep = TAILQ_FIRST(&g_events); 253 if (ep == NULL) { 254 wakeup(&g_pending_events); 255 return (0); 256 } 257 if (ep->flag & EV_INPROGRESS) { 258 mtx_unlock(&g_eventlock); 259 return (1); 260 } 261 ep->flag |= EV_INPROGRESS; 262 mtx_unlock(&g_eventlock); 263 g_topology_assert(); 264 ep->func(ep->arg, 0); 265 g_topology_assert(); 266 mtx_lock(&g_eventlock); 267 TAILQ_REMOVE(&g_events, ep, events); 268 ep->flag &= ~EV_INPROGRESS; 269 if (ep->flag & EV_WAKEUP) { 270 ep->flag |= EV_DONE; 271 mtx_unlock(&g_eventlock); 272 wakeup(ep); 273 } else { 274 mtx_unlock(&g_eventlock); 275 g_free(ep); 276 } 277 return (1); 278 } 279 280 void 281 g_run_events() 282 { 283 284 for (;;) { 285 g_topology_lock(); 286 while (one_event()) 287 ; 288 mtx_assert(&g_eventlock, MA_OWNED); 289 if (g_wither_work) { 290 g_wither_work = 0; 291 mtx_unlock(&g_eventlock); 292 g_wither_washer(); 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 } 441