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 #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(struct thread *td) 83 { 84 85 g_topology_assert_not(); 86 87 mtx_lock(&g_eventlock); 88 TSWAIT("GEOM events"); 89 while (!TAILQ_EMPTY(&g_events)) 90 msleep(&g_pending_events, &g_eventlock, PPAUSE, 91 "g_waitidle", 0); 92 TSUNWAIT("GEOM events"); 93 mtx_unlock(&g_eventlock); 94 td->td_pflags &= ~TDP_GEOM; 95 } 96 97 static void 98 ast_geom(struct thread *td, int tda __unused) 99 { 100 /* 101 * If this thread tickled GEOM, we need to wait for the giggling to 102 * stop before we return to userland. 103 */ 104 g_waitidle(td); 105 } 106 107 static void 108 geom_event_init(void *arg __unused) 109 { 110 ast_register(TDA_GEOM, ASTR_ASTF_REQUIRED | ASTR_TDP | ASTR_KCLEAR, 111 TDP_GEOM, ast_geom); 112 } 113 SYSINIT(geom_event, SI_SUB_INTRINSIC, SI_ORDER_ANY, geom_event_init, NULL); 114 115 struct g_attrchanged_args { 116 struct g_provider *pp; 117 const char *attr; 118 }; 119 120 static void 121 g_attr_changed_event(void *arg, int flag) 122 { 123 struct g_attrchanged_args *args; 124 struct g_provider *pp; 125 struct g_consumer *cp; 126 struct g_consumer *next_cp; 127 128 args = arg; 129 pp = args->pp; 130 131 g_topology_assert(); 132 if (flag != EV_CANCEL && g_shutdown == 0) { 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 pp = TAILQ_FIRST(&g_doorstep); 243 if (pp != NULL) { 244 G_VALID_PROVIDER(pp); 245 TAILQ_REMOVE(&g_doorstep, pp, orphan); 246 mtx_unlock(&g_eventlock); 247 g_orphan_register(pp); 248 return (1); 249 } 250 251 ep = TAILQ_FIRST(&g_events); 252 if (ep == NULL) { 253 wakeup(&g_pending_events); 254 return (0); 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 TSRELEASE("GEOM events"); 263 TAILQ_REMOVE(&g_events, ep, events); 264 ep->flag &= ~EV_INPROGRESS; 265 if (ep->flag & EV_WAKEUP) { 266 ep->flag |= EV_DONE; 267 wakeup(ep); 268 mtx_unlock(&g_eventlock); 269 } else { 270 mtx_unlock(&g_eventlock); 271 g_free(ep); 272 } 273 return (1); 274 } 275 276 void 277 g_run_events(void) 278 { 279 280 for (;;) { 281 g_topology_lock(); 282 while (one_event()) 283 ; 284 mtx_assert(&g_eventlock, MA_OWNED); 285 if (g_wither_work) { 286 g_wither_work = 0; 287 mtx_unlock(&g_eventlock); 288 g_wither_washer(); 289 g_topology_unlock(); 290 } else { 291 g_topology_unlock(); 292 msleep(&g_wait_event, &g_eventlock, PRIBIO | PDROP, 293 "-", 0); 294 } 295 } 296 /* NOTREACHED */ 297 } 298 299 void 300 g_cancel_event(void *ref) 301 { 302 struct g_event *ep, *epn; 303 struct g_provider *pp; 304 u_int n; 305 306 mtx_lock(&g_eventlock); 307 TAILQ_FOREACH(pp, &g_doorstep, orphan) { 308 if (pp != ref) 309 continue; 310 TAILQ_REMOVE(&g_doorstep, pp, orphan); 311 break; 312 } 313 TAILQ_FOREACH_SAFE(ep, &g_events, events, epn) { 314 if (ep->flag & EV_INPROGRESS) 315 continue; 316 for (n = 0; n < G_N_EVENTREFS; n++) { 317 if (ep->ref[n] == NULL) 318 break; 319 if (ep->ref[n] != ref) 320 continue; 321 TSRELEASE("GEOM events"); 322 TAILQ_REMOVE(&g_events, ep, events); 323 ep->func(ep->arg, EV_CANCEL); 324 mtx_assert(&g_eventlock, MA_OWNED); 325 if (ep->flag & EV_WAKEUP) { 326 ep->flag |= (EV_DONE|EV_CANCELED); 327 wakeup(ep); 328 } else { 329 g_free(ep); 330 } 331 break; 332 } 333 } 334 if (TAILQ_EMPTY(&g_events)) 335 wakeup(&g_pending_events); 336 mtx_unlock(&g_eventlock); 337 } 338 339 struct g_event * 340 g_alloc_event(int flag) 341 { 342 KASSERT(flag == M_WAITOK || flag == M_NOWAIT, 343 ("Wrong flag to g_alloc_event")); 344 345 return (g_malloc(sizeof(struct g_event), flag | M_ZERO)); 346 } 347 348 static void 349 g_post_event_ep_va(g_event_t *func, void *arg, int wuflag, 350 struct g_event *ep, va_list ap) 351 { 352 void *p; 353 u_int n; 354 355 ep->flag = wuflag; 356 for (n = 0; n < G_N_EVENTREFS; n++) { 357 p = va_arg(ap, void *); 358 if (p == NULL) 359 break; 360 g_trace(G_T_TOPOLOGY, " ref %p", p); 361 ep->ref[n] = p; 362 } 363 KASSERT(p == NULL, ("Too many references to event")); 364 ep->func = func; 365 ep->arg = arg; 366 mtx_lock(&g_eventlock); 367 TSHOLD("GEOM events"); 368 TAILQ_INSERT_TAIL(&g_events, ep, events); 369 mtx_unlock(&g_eventlock); 370 wakeup(&g_wait_event); 371 curthread->td_pflags |= TDP_GEOM; 372 ast_sched(curthread, TDA_GEOM); 373 } 374 375 void 376 g_post_event_ep(g_event_t *func, void *arg, struct g_event *ep, ...) 377 { 378 va_list ap; 379 380 va_start(ap, ep); 381 g_post_event_ep_va(func, arg, 0, ep, ap); 382 va_end(ap); 383 } 384 385 386 static int 387 g_post_event_x(g_event_t *func, void *arg, int flag, int wuflag, struct g_event **epp, va_list ap) 388 { 389 struct g_event *ep; 390 391 g_trace(G_T_TOPOLOGY, "g_post_event_x(%p, %p, %d, %d)", 392 func, arg, flag, wuflag); 393 KASSERT(wuflag == 0 || wuflag == EV_WAKEUP, 394 ("Wrong wuflag in g_post_event_x(0x%x)", wuflag)); 395 ep = g_alloc_event(flag); 396 if (ep == NULL) 397 return (ENOMEM); 398 if (epp != NULL) 399 *epp = ep; 400 g_post_event_ep_va(func, arg, wuflag, ep, ap); 401 return (0); 402 } 403 404 int 405 g_post_event(g_event_t *func, void *arg, int flag, ...) 406 { 407 va_list ap; 408 int i; 409 410 KASSERT(flag == M_WAITOK || flag == M_NOWAIT, 411 ("Wrong flag to g_post_event")); 412 va_start(ap, flag); 413 i = g_post_event_x(func, arg, flag, 0, NULL, ap); 414 va_end(ap); 415 return (i); 416 } 417 418 void 419 g_do_wither(void) 420 { 421 422 mtx_lock(&g_eventlock); 423 g_wither_work = 1; 424 mtx_unlock(&g_eventlock); 425 wakeup(&g_wait_event); 426 } 427 428 /* 429 * XXX: It might actually be useful to call this function with topology held. 430 * XXX: This would ensure that the event gets created before anything else 431 * XXX: changes. At present all users have a handle on things in some other 432 * XXX: way, so this remains an XXX for now. 433 */ 434 435 int 436 g_waitfor_event(g_event_t *func, void *arg, int flag, ...) 437 { 438 va_list ap; 439 struct g_event *ep; 440 int error; 441 442 g_topology_assert_not(); 443 KASSERT(flag == M_WAITOK || flag == M_NOWAIT, 444 ("Wrong flag to g_post_event")); 445 va_start(ap, flag); 446 error = g_post_event_x(func, arg, flag, EV_WAKEUP, &ep, ap); 447 va_end(ap); 448 if (error) 449 return (error); 450 451 mtx_lock(&g_eventlock); 452 while (!(ep->flag & EV_DONE)) 453 msleep(ep, &g_eventlock, PRIBIO, "g_waitfor_event", 0); 454 if (ep->flag & EV_CANCELED) 455 error = EAGAIN; 456 mtx_unlock(&g_eventlock); 457 458 g_free(ep); 459 return (error); 460 } 461 462 void 463 g_event_init(void) 464 { 465 466 mtx_init(&g_eventlock, "GEOM orphanage", NULL, MTX_DEF); 467 } 468