1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 2002 Poul-Henning Kamp 5 * Copyright (c) 2002 Networks Associates Technology, Inc. 6 * All rights reserved. 7 * 8 * This software was developed for the FreeBSD Project by Poul-Henning Kamp 9 * and NAI Labs, the Security Research Division of Network Associates, Inc. 10 * under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the 11 * DARPA CHATS research program. 12 * 13 * Redistribution and use in source and binary forms, with or without 14 * modification, are permitted provided that the following conditions 15 * are met: 16 * 1. Redistributions of source code must retain the above copyright 17 * notice, this list of conditions and the following disclaimer. 18 * 2. Redistributions in binary form must reproduce the above copyright 19 * notice, this list of conditions and the following disclaimer in the 20 * documentation and/or other materials provided with the distribution. 21 * 3. The names of the authors may not be used to endorse or promote 22 * products derived from this software without specific prior written 23 * permission. 24 * 25 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 28 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 35 * SUCH DAMAGE. 36 */ 37 38 /* 39 * XXX: How do we in general know that objects referenced in events 40 * have not been destroyed before we get around to handle the event ? 41 */ 42 43 #include <sys/cdefs.h> 44 __FBSDID("$FreeBSD$"); 45 46 #include <sys/param.h> 47 #include <sys/malloc.h> 48 #include <sys/systm.h> 49 #include <sys/kernel.h> 50 #include <sys/lock.h> 51 #include <sys/mutex.h> 52 #include <sys/proc.h> 53 #include <sys/errno.h> 54 #include <sys/time.h> 55 #include <geom/geom.h> 56 #include <geom/geom_int.h> 57 58 #include <machine/stdarg.h> 59 60 TAILQ_HEAD(event_tailq_head, g_event); 61 62 static struct event_tailq_head g_events = TAILQ_HEAD_INITIALIZER(g_events); 63 static u_int g_pending_events; 64 static TAILQ_HEAD(,g_provider) g_doorstep = TAILQ_HEAD_INITIALIZER(g_doorstep); 65 static struct mtx g_eventlock; 66 static int g_wither_work; 67 68 #define G_N_EVENTREFS 20 69 70 struct g_event { 71 TAILQ_ENTRY(g_event) events; 72 g_event_t *func; 73 void *arg; 74 int flag; 75 void *ref[G_N_EVENTREFS]; 76 }; 77 78 #define EV_DONE 0x80000 79 #define EV_WAKEUP 0x40000 80 #define EV_CANCELED 0x20000 81 #define EV_INPROGRESS 0x10000 82 83 void 84 g_waitidle(void) 85 { 86 87 g_topology_assert_not(); 88 89 mtx_lock(&g_eventlock); 90 while (!TAILQ_EMPTY(&g_events)) 91 msleep(&g_pending_events, &g_eventlock, PPAUSE, 92 "g_waitidle", hz/5); 93 mtx_unlock(&g_eventlock); 94 curthread->td_pflags &= ~TDP_GEOM; 95 } 96 97 #if 0 98 void 99 g_waitidlelock(void) 100 { 101 102 g_topology_assert(); 103 mtx_lock(&g_eventlock); 104 while (!TAILQ_EMPTY(&g_events)) { 105 g_topology_unlock(); 106 msleep(&g_pending_events, &g_eventlock, PPAUSE, 107 "g_waitidlel", hz/5); 108 g_topology_lock(); 109 } 110 mtx_unlock(&g_eventlock); 111 } 112 #endif 113 114 struct g_attrchanged_args { 115 struct g_provider *pp; 116 const char *attr; 117 }; 118 119 static void 120 g_attr_changed_event(void *arg, int flag) 121 { 122 struct g_attrchanged_args *args; 123 struct g_provider *pp; 124 struct g_consumer *cp; 125 struct g_consumer *next_cp; 126 127 args = arg; 128 pp = args->pp; 129 130 g_topology_assert(); 131 if (flag != EV_CANCEL && g_shutdown == 0) { 132 133 /* 134 * Tell all consumers of the change. 135 */ 136 LIST_FOREACH_SAFE(cp, &pp->consumers, consumers, next_cp) { 137 if (cp->geom->attrchanged != NULL) 138 cp->geom->attrchanged(cp, args->attr); 139 } 140 } 141 g_free(args); 142 } 143 144 int 145 g_attr_changed(struct g_provider *pp, const char *attr, int flag) 146 { 147 struct g_attrchanged_args *args; 148 int error; 149 150 args = g_malloc(sizeof *args, flag); 151 if (args == NULL) 152 return (ENOMEM); 153 args->pp = pp; 154 args->attr = attr; 155 error = g_post_event(g_attr_changed_event, args, flag, pp, NULL); 156 if (error != 0) 157 g_free(args); 158 return (error); 159 } 160 161 void 162 g_orphan_provider(struct g_provider *pp, int error) 163 { 164 165 /* G_VALID_PROVIDER(pp) We likely lack topology lock */ 166 g_trace(G_T_TOPOLOGY, "g_orphan_provider(%p(%s), %d)", 167 pp, pp->name, error); 168 KASSERT(error != 0, 169 ("g_orphan_provider(%p(%s), 0) error must be non-zero\n", 170 pp, pp->name)); 171 172 pp->error = error; 173 mtx_lock(&g_eventlock); 174 KASSERT(!(pp->flags & G_PF_ORPHAN), 175 ("g_orphan_provider(%p(%s)), already an orphan", pp, pp->name)); 176 pp->flags |= G_PF_ORPHAN; 177 TAILQ_INSERT_TAIL(&g_doorstep, pp, orphan); 178 mtx_unlock(&g_eventlock); 179 wakeup(&g_wait_event); 180 } 181 182 /* 183 * This function is called once on each provider which the event handler 184 * finds on its g_doorstep. 185 */ 186 187 static void 188 g_orphan_register(struct g_provider *pp) 189 { 190 struct g_consumer *cp, *cp2; 191 int wf; 192 193 g_topology_assert(); 194 G_VALID_PROVIDER(pp); 195 g_trace(G_T_TOPOLOGY, "g_orphan_register(%s)", pp->name); 196 197 g_cancel_event(pp); 198 199 wf = pp->flags & G_PF_WITHER; 200 pp->flags &= ~G_PF_WITHER; 201 202 /* 203 * Tell all consumers the bad news. 204 * Don't be surprised if they self-destruct. 205 */ 206 LIST_FOREACH_SAFE(cp, &pp->consumers, consumers, cp2) { 207 KASSERT(cp->geom->orphan != NULL, 208 ("geom %s has no orphan, class %s", 209 cp->geom->name, cp->geom->class->name)); 210 /* 211 * XXX: g_dev_orphan method does deferred destroying 212 * and it is possible, that other event could already 213 * call the orphan method. Check consumer's flags to 214 * do not schedule it twice. 215 */ 216 if (cp->flags & G_CF_ORPHAN) 217 continue; 218 cp->flags |= G_CF_ORPHAN; 219 cp->geom->orphan(cp); 220 } 221 if (LIST_EMPTY(&pp->consumers) && wf) 222 g_destroy_provider(pp); 223 else 224 pp->flags |= wf; 225 #ifdef notyet 226 cp = LIST_FIRST(&pp->consumers); 227 if (cp != NULL) 228 return; 229 if (pp->geom->flags & G_GEOM_WITHER) 230 g_destroy_provider(pp); 231 #endif 232 } 233 234 static int 235 one_event(void) 236 { 237 struct g_event *ep; 238 struct g_provider *pp; 239 240 g_topology_assert(); 241 mtx_lock(&g_eventlock); 242 TAILQ_FOREACH(pp, &g_doorstep, orphan) { 243 if (pp->nstart == pp->nend) 244 break; 245 } 246 if (pp != NULL) { 247 G_VALID_PROVIDER(pp); 248 TAILQ_REMOVE(&g_doorstep, pp, orphan); 249 mtx_unlock(&g_eventlock); 250 g_orphan_register(pp); 251 return (1); 252 } 253 254 ep = TAILQ_FIRST(&g_events); 255 if (ep == NULL) { 256 wakeup(&g_pending_events); 257 return (0); 258 } 259 if (ep->flag & EV_INPROGRESS) { 260 mtx_unlock(&g_eventlock); 261 return (1); 262 } 263 ep->flag |= EV_INPROGRESS; 264 mtx_unlock(&g_eventlock); 265 g_topology_assert(); 266 ep->func(ep->arg, 0); 267 g_topology_assert(); 268 mtx_lock(&g_eventlock); 269 TAILQ_REMOVE(&g_events, ep, events); 270 ep->flag &= ~EV_INPROGRESS; 271 if (ep->flag & EV_WAKEUP) { 272 ep->flag |= EV_DONE; 273 mtx_unlock(&g_eventlock); 274 wakeup(ep); 275 } else { 276 mtx_unlock(&g_eventlock); 277 g_free(ep); 278 } 279 return (1); 280 } 281 282 void 283 g_run_events() 284 { 285 286 for (;;) { 287 g_topology_lock(); 288 while (one_event()) 289 ; 290 mtx_assert(&g_eventlock, MA_OWNED); 291 if (g_wither_work) { 292 g_wither_work = 0; 293 mtx_unlock(&g_eventlock); 294 g_wither_washer(); 295 g_topology_unlock(); 296 } else { 297 g_topology_unlock(); 298 msleep(&g_wait_event, &g_eventlock, PRIBIO | PDROP, 299 "-", TAILQ_EMPTY(&g_doorstep) ? 0 : hz / 10); 300 } 301 } 302 /* NOTREACHED */ 303 } 304 305 void 306 g_cancel_event(void *ref) 307 { 308 struct g_event *ep, *epn; 309 struct g_provider *pp; 310 u_int n; 311 312 mtx_lock(&g_eventlock); 313 TAILQ_FOREACH(pp, &g_doorstep, orphan) { 314 if (pp != ref) 315 continue; 316 TAILQ_REMOVE(&g_doorstep, pp, orphan); 317 break; 318 } 319 TAILQ_FOREACH_SAFE(ep, &g_events, events, epn) { 320 if (ep->flag & EV_INPROGRESS) 321 continue; 322 for (n = 0; n < G_N_EVENTREFS; n++) { 323 if (ep->ref[n] == NULL) 324 break; 325 if (ep->ref[n] != ref) 326 continue; 327 TAILQ_REMOVE(&g_events, ep, events); 328 ep->func(ep->arg, EV_CANCEL); 329 mtx_assert(&g_eventlock, MA_OWNED); 330 if (ep->flag & EV_WAKEUP) { 331 ep->flag |= (EV_DONE|EV_CANCELED); 332 wakeup(ep); 333 } else { 334 g_free(ep); 335 } 336 break; 337 } 338 } 339 if (TAILQ_EMPTY(&g_events)) 340 wakeup(&g_pending_events); 341 mtx_unlock(&g_eventlock); 342 } 343 344 static int 345 g_post_event_x(g_event_t *func, void *arg, int flag, int wuflag, struct g_event **epp, va_list ap) 346 { 347 struct g_event *ep; 348 void *p; 349 u_int n; 350 351 g_trace(G_T_TOPOLOGY, "g_post_event_x(%p, %p, %d, %d)", 352 func, arg, flag, wuflag); 353 KASSERT(wuflag == 0 || wuflag == EV_WAKEUP, 354 ("Wrong wuflag in g_post_event_x(0x%x)", wuflag)); 355 ep = g_malloc(sizeof *ep, flag | M_ZERO); 356 if (ep == NULL) 357 return (ENOMEM); 358 ep->flag = wuflag; 359 for (n = 0; n < G_N_EVENTREFS; n++) { 360 p = va_arg(ap, void *); 361 if (p == NULL) 362 break; 363 g_trace(G_T_TOPOLOGY, " ref %p", p); 364 ep->ref[n] = p; 365 } 366 KASSERT(p == NULL, ("Too many references to event")); 367 ep->func = func; 368 ep->arg = arg; 369 mtx_lock(&g_eventlock); 370 TAILQ_INSERT_TAIL(&g_events, ep, events); 371 mtx_unlock(&g_eventlock); 372 wakeup(&g_wait_event); 373 if (epp != NULL) 374 *epp = ep; 375 curthread->td_pflags |= TDP_GEOM; 376 return (0); 377 } 378 379 int 380 g_post_event(g_event_t *func, void *arg, int flag, ...) 381 { 382 va_list ap; 383 int i; 384 385 KASSERT(flag == M_WAITOK || flag == M_NOWAIT, 386 ("Wrong flag to g_post_event")); 387 va_start(ap, flag); 388 i = g_post_event_x(func, arg, flag, 0, NULL, ap); 389 va_end(ap); 390 return (i); 391 } 392 393 void 394 g_do_wither() 395 { 396 397 mtx_lock(&g_eventlock); 398 g_wither_work = 1; 399 mtx_unlock(&g_eventlock); 400 wakeup(&g_wait_event); 401 } 402 403 /* 404 * XXX: It might actually be useful to call this function with topology held. 405 * XXX: This would ensure that the event gets created before anything else 406 * XXX: changes. At present all users have a handle on things in some other 407 * XXX: way, so this remains an XXX for now. 408 */ 409 410 int 411 g_waitfor_event(g_event_t *func, void *arg, int flag, ...) 412 { 413 va_list ap; 414 struct g_event *ep; 415 int error; 416 417 g_topology_assert_not(); 418 KASSERT(flag == M_WAITOK || flag == M_NOWAIT, 419 ("Wrong flag to g_post_event")); 420 va_start(ap, flag); 421 error = g_post_event_x(func, arg, flag, EV_WAKEUP, &ep, ap); 422 va_end(ap); 423 if (error) 424 return (error); 425 426 mtx_lock(&g_eventlock); 427 while (!(ep->flag & EV_DONE)) 428 msleep(ep, &g_eventlock, PRIBIO, "g_waitfor_event", hz); 429 if (ep->flag & EV_CANCELED) 430 error = EAGAIN; 431 mtx_unlock(&g_eventlock); 432 433 g_free(ep); 434 return (error); 435 } 436 437 void 438 g_event_init() 439 { 440 441 mtx_init(&g_eventlock, "GEOM orphanage", NULL, MTX_DEF); 442 } 443