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 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 } 441