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/param.h> 44 #include <sys/malloc.h> 45 #include <sys/systm.h> 46 #include <sys/kernel.h> 47 #include <sys/lock.h> 48 #include <sys/mutex.h> 49 #include <sys/proc.h> 50 #include <sys/errno.h> 51 #include <sys/stdarg.h> 52 #include <sys/time.h> 53 #include <geom/geom.h> 54 #include <geom/geom_int.h> 55 56 TAILQ_HEAD(event_tailq_head, g_event); 57 58 static struct event_tailq_head g_events = TAILQ_HEAD_INITIALIZER(g_events); 59 static u_int g_pending_events; 60 static TAILQ_HEAD(,g_provider) g_doorstep = TAILQ_HEAD_INITIALIZER(g_doorstep); 61 static struct mtx g_eventlock; 62 static int g_wither_work; 63 64 #define G_N_EVENTREFS 20 65 66 struct g_event { 67 TAILQ_ENTRY(g_event) events; 68 g_event_t *func; 69 void *arg; 70 int flag; 71 void *ref[G_N_EVENTREFS]; 72 }; 73 74 #define EV_DONE 0x80000 75 #define EV_WAKEUP 0x40000 76 #define EV_CANCELED 0x20000 77 #define EV_INPROGRESS 0x10000 78 79 void 80 g_waitidle(struct thread *td) 81 { 82 83 g_topology_assert_not(); 84 85 mtx_lock(&g_eventlock); 86 TSWAIT("GEOM events"); 87 while (!TAILQ_EMPTY(&g_events)) 88 msleep(&g_pending_events, &g_eventlock, PPAUSE, 89 "g_waitidle", 0); 90 TSUNWAIT("GEOM events"); 91 mtx_unlock(&g_eventlock); 92 td->td_pflags &= ~TDP_GEOM; 93 } 94 95 static void 96 ast_geom(struct thread *td, int tda __unused) 97 { 98 /* 99 * If this thread tickled GEOM, we need to wait for the giggling to 100 * stop before we return to userland. 101 */ 102 g_waitidle(td); 103 } 104 105 static void 106 geom_event_init(void *arg __unused) 107 { 108 ast_register(TDA_GEOM, ASTR_ASTF_REQUIRED | ASTR_TDP | ASTR_KCLEAR, 109 TDP_GEOM, ast_geom); 110 } 111 SYSINIT(geom_event, SI_SUB_INTRINSIC, SI_ORDER_ANY, geom_event_init, NULL); 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 * 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 pp = TAILQ_FIRST(&g_doorstep); 241 if (pp != NULL) { 242 G_VALID_PROVIDER(pp); 243 TAILQ_REMOVE(&g_doorstep, pp, orphan); 244 mtx_unlock(&g_eventlock); 245 g_orphan_register(pp); 246 return (1); 247 } 248 249 ep = TAILQ_FIRST(&g_events); 250 if (ep == NULL) { 251 wakeup(&g_pending_events); 252 return (0); 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 TSRELEASE("GEOM events"); 261 TAILQ_REMOVE(&g_events, ep, events); 262 ep->flag &= ~EV_INPROGRESS; 263 if (ep->flag & EV_WAKEUP) { 264 ep->flag |= EV_DONE; 265 wakeup(ep); 266 mtx_unlock(&g_eventlock); 267 } else { 268 mtx_unlock(&g_eventlock); 269 g_free(ep); 270 } 271 return (1); 272 } 273 274 void 275 g_run_events(void) 276 { 277 278 for (;;) { 279 g_topology_lock(); 280 while (one_event()) 281 ; 282 mtx_assert(&g_eventlock, MA_OWNED); 283 if (g_wither_work) { 284 g_wither_work = 0; 285 mtx_unlock(&g_eventlock); 286 g_wither_washer(); 287 g_topology_unlock(); 288 } else { 289 g_topology_unlock(); 290 msleep(&g_wait_event, &g_eventlock, PRIBIO | PDROP, 291 "-", 0); 292 } 293 } 294 /* NOTREACHED */ 295 } 296 297 void 298 g_cancel_event(void *ref) 299 { 300 struct g_event *ep, *epn; 301 struct g_provider *pp; 302 u_int n; 303 304 mtx_lock(&g_eventlock); 305 TAILQ_FOREACH(pp, &g_doorstep, orphan) { 306 if (pp != ref) 307 continue; 308 TAILQ_REMOVE(&g_doorstep, pp, orphan); 309 break; 310 } 311 TAILQ_FOREACH_SAFE(ep, &g_events, events, epn) { 312 if (ep->flag & EV_INPROGRESS) 313 continue; 314 for (n = 0; n < G_N_EVENTREFS; n++) { 315 if (ep->ref[n] == NULL) 316 break; 317 if (ep->ref[n] != ref) 318 continue; 319 TSRELEASE("GEOM events"); 320 TAILQ_REMOVE(&g_events, ep, events); 321 ep->func(ep->arg, EV_CANCEL); 322 mtx_assert(&g_eventlock, MA_OWNED); 323 if (ep->flag & EV_WAKEUP) { 324 ep->flag |= (EV_DONE|EV_CANCELED); 325 wakeup(ep); 326 } else { 327 g_free(ep); 328 } 329 break; 330 } 331 } 332 if (TAILQ_EMPTY(&g_events)) 333 wakeup(&g_pending_events); 334 mtx_unlock(&g_eventlock); 335 } 336 337 struct g_event * 338 g_alloc_event(int flag) 339 { 340 KASSERT(flag == M_WAITOK || flag == M_NOWAIT, 341 ("Wrong flag to g_alloc_event")); 342 343 return (g_malloc(sizeof(struct g_event), flag | M_ZERO)); 344 } 345 346 static void 347 g_post_event_ep_va(g_event_t *func, void *arg, int wuflag, 348 struct g_event *ep, va_list ap) 349 { 350 void *p; 351 u_int n; 352 353 ep->flag = wuflag; 354 for (n = 0; n < G_N_EVENTREFS; n++) { 355 p = va_arg(ap, void *); 356 if (p == NULL) 357 break; 358 g_trace(G_T_TOPOLOGY, " ref %p", p); 359 ep->ref[n] = p; 360 } 361 KASSERT(p == NULL, ("Too many references to event")); 362 ep->func = func; 363 ep->arg = arg; 364 mtx_lock(&g_eventlock); 365 TSHOLD("GEOM events"); 366 TAILQ_INSERT_TAIL(&g_events, ep, events); 367 mtx_unlock(&g_eventlock); 368 wakeup(&g_wait_event); 369 curthread->td_pflags |= TDP_GEOM; 370 ast_sched(curthread, TDA_GEOM); 371 } 372 373 void 374 g_post_event_ep(g_event_t *func, void *arg, struct g_event *ep, ...) 375 { 376 va_list ap; 377 378 va_start(ap, ep); 379 g_post_event_ep_va(func, arg, 0, ep, ap); 380 va_end(ap); 381 } 382 383 384 static int 385 g_post_event_x(g_event_t *func, void *arg, int flag, int wuflag, struct g_event **epp, va_list ap) 386 { 387 struct g_event *ep; 388 389 g_trace(G_T_TOPOLOGY, "g_post_event_x(%p, %p, %d, %d)", 390 func, arg, flag, wuflag); 391 KASSERT(wuflag == 0 || wuflag == EV_WAKEUP, 392 ("Wrong wuflag in g_post_event_x(0x%x)", wuflag)); 393 ep = g_alloc_event(flag); 394 if (ep == NULL) 395 return (ENOMEM); 396 if (epp != NULL) 397 *epp = ep; 398 g_post_event_ep_va(func, arg, wuflag, ep, ap); 399 return (0); 400 } 401 402 int 403 g_post_event(g_event_t *func, void *arg, int flag, ...) 404 { 405 va_list ap; 406 int i; 407 408 KASSERT(flag == M_WAITOK || flag == M_NOWAIT, 409 ("Wrong flag to g_post_event")); 410 va_start(ap, flag); 411 i = g_post_event_x(func, arg, flag, 0, NULL, ap); 412 va_end(ap); 413 return (i); 414 } 415 416 void 417 g_do_wither(void) 418 { 419 420 mtx_lock(&g_eventlock); 421 g_wither_work = 1; 422 mtx_unlock(&g_eventlock); 423 wakeup(&g_wait_event); 424 } 425 426 /* 427 * XXX: It might actually be useful to call this function with topology held. 428 * XXX: This would ensure that the event gets created before anything else 429 * XXX: changes. At present all users have a handle on things in some other 430 * XXX: way, so this remains an XXX for now. 431 */ 432 433 int 434 g_waitfor_event(g_event_t *func, void *arg, int flag, ...) 435 { 436 va_list ap; 437 struct g_event *ep; 438 int error; 439 440 g_topology_assert_not(); 441 KASSERT(flag == M_WAITOK || flag == M_NOWAIT, 442 ("Wrong flag to g_post_event")); 443 va_start(ap, flag); 444 error = g_post_event_x(func, arg, flag, EV_WAKEUP, &ep, ap); 445 va_end(ap); 446 if (error) 447 return (error); 448 449 mtx_lock(&g_eventlock); 450 while (!(ep->flag & EV_DONE)) 451 msleep(ep, &g_eventlock, PRIBIO, "g_waitfor_event", 0); 452 if (ep->flag & EV_CANCELED) 453 error = EAGAIN; 454 mtx_unlock(&g_eventlock); 455 456 g_free(ep); 457 return (error); 458 } 459 460 void 461 g_event_init(void) 462 { 463 464 mtx_init(&g_eventlock, "GEOM orphanage", NULL, MTX_DEF); 465 } 466