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 cp->flags |= G_CF_ORPHAN; 210 cp->geom->orphan(cp); 211 } 212 if (LIST_EMPTY(&pp->consumers) && wf) 213 g_destroy_provider(pp); 214 else 215 pp->flags |= wf; 216 #ifdef notyet 217 cp = LIST_FIRST(&pp->consumers); 218 if (cp != NULL) 219 return; 220 if (pp->geom->flags & G_GEOM_WITHER) 221 g_destroy_provider(pp); 222 #endif 223 } 224 225 static int 226 one_event(void) 227 { 228 struct g_event *ep; 229 struct g_provider *pp; 230 231 g_topology_assert(); 232 mtx_lock(&g_eventlock); 233 TAILQ_FOREACH(pp, &g_doorstep, orphan) { 234 if (pp->nstart == pp->nend) 235 break; 236 } 237 if (pp != NULL) { 238 G_VALID_PROVIDER(pp); 239 TAILQ_REMOVE(&g_doorstep, pp, orphan); 240 mtx_unlock(&g_eventlock); 241 g_orphan_register(pp); 242 return (1); 243 } 244 245 ep = TAILQ_FIRST(&g_events); 246 if (ep == NULL) { 247 wakeup(&g_pending_events); 248 return (0); 249 } 250 if (ep->flag & EV_INPROGRESS) { 251 mtx_unlock(&g_eventlock); 252 return (1); 253 } 254 ep->flag |= EV_INPROGRESS; 255 mtx_unlock(&g_eventlock); 256 g_topology_assert(); 257 ep->func(ep->arg, 0); 258 g_topology_assert(); 259 mtx_lock(&g_eventlock); 260 TAILQ_REMOVE(&g_events, ep, events); 261 ep->flag &= ~EV_INPROGRESS; 262 if (ep->flag & EV_WAKEUP) { 263 ep->flag |= EV_DONE; 264 mtx_unlock(&g_eventlock); 265 wakeup(ep); 266 } else { 267 mtx_unlock(&g_eventlock); 268 g_free(ep); 269 } 270 return (1); 271 } 272 273 void 274 g_run_events() 275 { 276 277 for (;;) { 278 g_topology_lock(); 279 while (one_event()) 280 ; 281 mtx_assert(&g_eventlock, MA_OWNED); 282 if (g_wither_work) { 283 g_wither_work = 0; 284 mtx_unlock(&g_eventlock); 285 g_wither_washer(); 286 g_topology_unlock(); 287 } else { 288 g_topology_unlock(); 289 msleep(&g_wait_event, &g_eventlock, PRIBIO | PDROP, 290 "-", TAILQ_EMPTY(&g_doorstep) ? 0 : hz / 10); 291 } 292 } 293 /* NOTREACHED */ 294 } 295 296 void 297 g_cancel_event(void *ref) 298 { 299 struct g_event *ep, *epn; 300 struct g_provider *pp; 301 u_int n; 302 303 mtx_lock(&g_eventlock); 304 TAILQ_FOREACH(pp, &g_doorstep, orphan) { 305 if (pp != ref) 306 continue; 307 TAILQ_REMOVE(&g_doorstep, pp, orphan); 308 break; 309 } 310 TAILQ_FOREACH_SAFE(ep, &g_events, events, epn) { 311 if (ep->flag & EV_INPROGRESS) 312 continue; 313 for (n = 0; n < G_N_EVENTREFS; n++) { 314 if (ep->ref[n] == NULL) 315 break; 316 if (ep->ref[n] != ref) 317 continue; 318 TAILQ_REMOVE(&g_events, ep, events); 319 ep->func(ep->arg, EV_CANCEL); 320 mtx_assert(&g_eventlock, MA_OWNED); 321 if (ep->flag & EV_WAKEUP) { 322 ep->flag |= (EV_DONE|EV_CANCELED); 323 wakeup(ep); 324 } else { 325 g_free(ep); 326 } 327 break; 328 } 329 } 330 if (TAILQ_EMPTY(&g_events)) 331 wakeup(&g_pending_events); 332 mtx_unlock(&g_eventlock); 333 } 334 335 static int 336 g_post_event_x(g_event_t *func, void *arg, int flag, int wuflag, struct g_event **epp, va_list ap) 337 { 338 struct g_event *ep; 339 void *p; 340 u_int n; 341 342 g_trace(G_T_TOPOLOGY, "g_post_event_x(%p, %p, %d, %d)", 343 func, arg, flag, wuflag); 344 KASSERT(wuflag == 0 || wuflag == EV_WAKEUP, 345 ("Wrong wuflag in g_post_event_x(0x%x)", wuflag)); 346 ep = g_malloc(sizeof *ep, flag | M_ZERO); 347 if (ep == NULL) 348 return (ENOMEM); 349 ep->flag = wuflag; 350 for (n = 0; n < G_N_EVENTREFS; n++) { 351 p = va_arg(ap, void *); 352 if (p == NULL) 353 break; 354 g_trace(G_T_TOPOLOGY, " ref %p", p); 355 ep->ref[n] = p; 356 } 357 KASSERT(p == NULL, ("Too many references to event")); 358 ep->func = func; 359 ep->arg = arg; 360 mtx_lock(&g_eventlock); 361 TAILQ_INSERT_TAIL(&g_events, ep, events); 362 mtx_unlock(&g_eventlock); 363 wakeup(&g_wait_event); 364 if (epp != NULL) 365 *epp = ep; 366 curthread->td_pflags |= TDP_GEOM; 367 return (0); 368 } 369 370 int 371 g_post_event(g_event_t *func, void *arg, int flag, ...) 372 { 373 va_list ap; 374 int i; 375 376 KASSERT(flag == M_WAITOK || flag == M_NOWAIT, 377 ("Wrong flag to g_post_event")); 378 va_start(ap, flag); 379 i = g_post_event_x(func, arg, flag, 0, NULL, ap); 380 va_end(ap); 381 return (i); 382 } 383 384 void 385 g_do_wither() 386 { 387 388 mtx_lock(&g_eventlock); 389 g_wither_work = 1; 390 mtx_unlock(&g_eventlock); 391 wakeup(&g_wait_event); 392 } 393 394 /* 395 * XXX: It might actually be useful to call this function with topology held. 396 * XXX: This would ensure that the event gets created before anything else 397 * XXX: changes. At present all users have a handle on things in some other 398 * XXX: way, so this remains an XXX for now. 399 */ 400 401 int 402 g_waitfor_event(g_event_t *func, void *arg, int flag, ...) 403 { 404 va_list ap; 405 struct g_event *ep; 406 int error; 407 408 g_topology_assert_not(); 409 KASSERT(flag == M_WAITOK || flag == M_NOWAIT, 410 ("Wrong flag to g_post_event")); 411 va_start(ap, flag); 412 error = g_post_event_x(func, arg, flag, EV_WAKEUP, &ep, ap); 413 va_end(ap); 414 if (error) 415 return (error); 416 417 mtx_lock(&g_eventlock); 418 while (!(ep->flag & EV_DONE)) 419 msleep(ep, &g_eventlock, PRIBIO, "g_waitfor_event", hz); 420 if (ep->flag & EV_CANCELED) 421 error = EAGAIN; 422 mtx_unlock(&g_eventlock); 423 424 g_free(ep); 425 return (error); 426 } 427 428 void 429 g_event_init() 430 { 431 432 mtx_init(&g_eventlock, "GEOM orphanage", NULL, MTX_DEF); 433 } 434