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(struct thread *td) 85 { 86 87 g_topology_assert_not(); 88 89 mtx_lock(&g_eventlock); 90 TSWAIT("GEOM events"); 91 while (!TAILQ_EMPTY(&g_events)) 92 msleep(&g_pending_events, &g_eventlock, PPAUSE, 93 "g_waitidle", 0); 94 TSUNWAIT("GEOM events"); 95 mtx_unlock(&g_eventlock); 96 td->td_pflags &= ~TDP_GEOM; 97 } 98 99 static void 100 ast_geom(struct thread *td, int tda __unused) 101 { 102 /* 103 * If this thread tickled GEOM, we need to wait for the giggling to 104 * stop before we return to userland. 105 */ 106 g_waitidle(td); 107 } 108 109 static void 110 geom_event_init(void *arg __unused) 111 { 112 ast_register(TDA_GEOM, ASTR_ASTF_REQUIRED | ASTR_TDP | ASTR_KCLEAR, 113 TDP_GEOM, ast_geom); 114 } 115 SYSINIT(geom_event, SI_SUB_INTRINSIC, SI_ORDER_ANY, geom_event_init, NULL); 116 117 struct g_attrchanged_args { 118 struct g_provider *pp; 119 const char *attr; 120 }; 121 122 static void 123 g_attr_changed_event(void *arg, int flag) 124 { 125 struct g_attrchanged_args *args; 126 struct g_provider *pp; 127 struct g_consumer *cp; 128 struct g_consumer *next_cp; 129 130 args = arg; 131 pp = args->pp; 132 133 g_topology_assert(); 134 if (flag != EV_CANCEL && g_shutdown == 0) { 135 /* 136 * Tell all consumers of the change. 137 */ 138 LIST_FOREACH_SAFE(cp, &pp->consumers, consumers, next_cp) { 139 if (cp->geom->attrchanged != NULL) 140 cp->geom->attrchanged(cp, args->attr); 141 } 142 } 143 g_free(args); 144 } 145 146 int 147 g_attr_changed(struct g_provider *pp, const char *attr, int flag) 148 { 149 struct g_attrchanged_args *args; 150 int error; 151 152 args = g_malloc(sizeof *args, flag); 153 if (args == NULL) 154 return (ENOMEM); 155 args->pp = pp; 156 args->attr = attr; 157 error = g_post_event(g_attr_changed_event, args, flag, pp, NULL); 158 if (error != 0) 159 g_free(args); 160 return (error); 161 } 162 163 void 164 g_orphan_provider(struct g_provider *pp, int error) 165 { 166 167 /* G_VALID_PROVIDER(pp) We likely lack topology lock */ 168 g_trace(G_T_TOPOLOGY, "g_orphan_provider(%p(%s), %d)", 169 pp, pp->name, error); 170 KASSERT(error != 0, 171 ("g_orphan_provider(%p(%s), 0) error must be non-zero\n", 172 pp, pp->name)); 173 174 pp->error = error; 175 mtx_lock(&g_eventlock); 176 KASSERT(!(pp->flags & G_PF_ORPHAN), 177 ("g_orphan_provider(%p(%s)), already an orphan", pp, pp->name)); 178 pp->flags |= G_PF_ORPHAN; 179 TAILQ_INSERT_TAIL(&g_doorstep, pp, orphan); 180 mtx_unlock(&g_eventlock); 181 wakeup(&g_wait_event); 182 } 183 184 /* 185 * This function is called once on each provider which the event handler 186 * finds on its g_doorstep. 187 */ 188 189 static void 190 g_orphan_register(struct g_provider *pp) 191 { 192 struct g_consumer *cp, *cp2; 193 int wf; 194 195 g_topology_assert(); 196 G_VALID_PROVIDER(pp); 197 g_trace(G_T_TOPOLOGY, "g_orphan_register(%s)", pp->name); 198 199 g_cancel_event(pp); 200 201 wf = pp->flags & G_PF_WITHER; 202 pp->flags &= ~G_PF_WITHER; 203 204 /* 205 * Tell all consumers the bad news. 206 * Don't be surprised if they self-destruct. 207 */ 208 LIST_FOREACH_SAFE(cp, &pp->consumers, consumers, cp2) { 209 KASSERT(cp->geom->orphan != NULL, 210 ("geom %s has no orphan, class %s", 211 cp->geom->name, cp->geom->class->name)); 212 /* 213 * XXX: g_dev_orphan method does deferred destroying 214 * and it is possible, that other event could already 215 * call the orphan method. Check consumer's flags to 216 * do not schedule it twice. 217 */ 218 if (cp->flags & G_CF_ORPHAN) 219 continue; 220 cp->flags |= G_CF_ORPHAN; 221 cp->geom->orphan(cp); 222 } 223 if (LIST_EMPTY(&pp->consumers) && wf) 224 g_destroy_provider(pp); 225 else 226 pp->flags |= wf; 227 #ifdef notyet 228 cp = LIST_FIRST(&pp->consumers); 229 if (cp != NULL) 230 return; 231 if (pp->geom->flags & G_GEOM_WITHER) 232 g_destroy_provider(pp); 233 #endif 234 } 235 236 static int 237 one_event(void) 238 { 239 struct g_event *ep; 240 struct g_provider *pp; 241 242 g_topology_assert(); 243 mtx_lock(&g_eventlock); 244 pp = TAILQ_FIRST(&g_doorstep); 245 if (pp != NULL) { 246 G_VALID_PROVIDER(pp); 247 TAILQ_REMOVE(&g_doorstep, pp, orphan); 248 mtx_unlock(&g_eventlock); 249 g_orphan_register(pp); 250 return (1); 251 } 252 253 ep = TAILQ_FIRST(&g_events); 254 if (ep == NULL) { 255 wakeup(&g_pending_events); 256 return (0); 257 } 258 ep->flag |= EV_INPROGRESS; 259 mtx_unlock(&g_eventlock); 260 g_topology_assert(); 261 ep->func(ep->arg, 0); 262 g_topology_assert(); 263 mtx_lock(&g_eventlock); 264 TSRELEASE("GEOM events"); 265 TAILQ_REMOVE(&g_events, ep, events); 266 ep->flag &= ~EV_INPROGRESS; 267 if (ep->flag & EV_WAKEUP) { 268 ep->flag |= EV_DONE; 269 wakeup(ep); 270 mtx_unlock(&g_eventlock); 271 } else { 272 mtx_unlock(&g_eventlock); 273 g_free(ep); 274 } 275 return (1); 276 } 277 278 void 279 g_run_events(void) 280 { 281 282 for (;;) { 283 g_topology_lock(); 284 while (one_event()) 285 ; 286 mtx_assert(&g_eventlock, MA_OWNED); 287 if (g_wither_work) { 288 g_wither_work = 0; 289 mtx_unlock(&g_eventlock); 290 g_wither_washer(); 291 g_topology_unlock(); 292 } else { 293 g_topology_unlock(); 294 msleep(&g_wait_event, &g_eventlock, PRIBIO | PDROP, 295 "-", 0); 296 } 297 } 298 /* NOTREACHED */ 299 } 300 301 void 302 g_cancel_event(void *ref) 303 { 304 struct g_event *ep, *epn; 305 struct g_provider *pp; 306 u_int n; 307 308 mtx_lock(&g_eventlock); 309 TAILQ_FOREACH(pp, &g_doorstep, orphan) { 310 if (pp != ref) 311 continue; 312 TAILQ_REMOVE(&g_doorstep, pp, orphan); 313 break; 314 } 315 TAILQ_FOREACH_SAFE(ep, &g_events, events, epn) { 316 if (ep->flag & EV_INPROGRESS) 317 continue; 318 for (n = 0; n < G_N_EVENTREFS; n++) { 319 if (ep->ref[n] == NULL) 320 break; 321 if (ep->ref[n] != ref) 322 continue; 323 TSRELEASE("GEOM events"); 324 TAILQ_REMOVE(&g_events, ep, events); 325 ep->func(ep->arg, EV_CANCEL); 326 mtx_assert(&g_eventlock, MA_OWNED); 327 if (ep->flag & EV_WAKEUP) { 328 ep->flag |= (EV_DONE|EV_CANCELED); 329 wakeup(ep); 330 } else { 331 g_free(ep); 332 } 333 break; 334 } 335 } 336 if (TAILQ_EMPTY(&g_events)) 337 wakeup(&g_pending_events); 338 mtx_unlock(&g_eventlock); 339 } 340 341 struct g_event * 342 g_alloc_event(int flag) 343 { 344 KASSERT(flag == M_WAITOK || flag == M_NOWAIT, 345 ("Wrong flag to g_alloc_event")); 346 347 return (g_malloc(sizeof(struct g_event), flag | M_ZERO)); 348 } 349 350 static void 351 g_post_event_ep_va(g_event_t *func, void *arg, int wuflag, 352 struct g_event *ep, va_list ap) 353 { 354 void *p; 355 u_int n; 356 357 ep->flag = wuflag; 358 for (n = 0; n < G_N_EVENTREFS; n++) { 359 p = va_arg(ap, void *); 360 if (p == NULL) 361 break; 362 g_trace(G_T_TOPOLOGY, " ref %p", p); 363 ep->ref[n] = p; 364 } 365 KASSERT(p == NULL, ("Too many references to event")); 366 ep->func = func; 367 ep->arg = arg; 368 mtx_lock(&g_eventlock); 369 TSHOLD("GEOM events"); 370 TAILQ_INSERT_TAIL(&g_events, ep, events); 371 mtx_unlock(&g_eventlock); 372 wakeup(&g_wait_event); 373 curthread->td_pflags |= TDP_GEOM; 374 ast_sched(curthread, TDA_GEOM); 375 } 376 377 void 378 g_post_event_ep(g_event_t *func, void *arg, struct g_event *ep, ...) 379 { 380 va_list ap; 381 382 va_start(ap, ep); 383 g_post_event_ep_va(func, arg, 0, ep, ap); 384 va_end(ap); 385 } 386 387 388 static int 389 g_post_event_x(g_event_t *func, void *arg, int flag, int wuflag, struct g_event **epp, va_list ap) 390 { 391 struct g_event *ep; 392 393 g_trace(G_T_TOPOLOGY, "g_post_event_x(%p, %p, %d, %d)", 394 func, arg, flag, wuflag); 395 KASSERT(wuflag == 0 || wuflag == EV_WAKEUP, 396 ("Wrong wuflag in g_post_event_x(0x%x)", wuflag)); 397 ep = g_alloc_event(flag); 398 if (ep == NULL) 399 return (ENOMEM); 400 if (epp != NULL) 401 *epp = ep; 402 g_post_event_ep_va(func, arg, wuflag, ep, ap); 403 return (0); 404 } 405 406 int 407 g_post_event(g_event_t *func, void *arg, int flag, ...) 408 { 409 va_list ap; 410 int i; 411 412 KASSERT(flag == M_WAITOK || flag == M_NOWAIT, 413 ("Wrong flag to g_post_event")); 414 va_start(ap, flag); 415 i = g_post_event_x(func, arg, flag, 0, NULL, ap); 416 va_end(ap); 417 return (i); 418 } 419 420 void 421 g_do_wither(void) 422 { 423 424 mtx_lock(&g_eventlock); 425 g_wither_work = 1; 426 mtx_unlock(&g_eventlock); 427 wakeup(&g_wait_event); 428 } 429 430 /* 431 * XXX: It might actually be useful to call this function with topology held. 432 * XXX: This would ensure that the event gets created before anything else 433 * XXX: changes. At present all users have a handle on things in some other 434 * XXX: way, so this remains an XXX for now. 435 */ 436 437 int 438 g_waitfor_event(g_event_t *func, void *arg, int flag, ...) 439 { 440 va_list ap; 441 struct g_event *ep; 442 int error; 443 444 g_topology_assert_not(); 445 KASSERT(flag == M_WAITOK || flag == M_NOWAIT, 446 ("Wrong flag to g_post_event")); 447 va_start(ap, flag); 448 error = g_post_event_x(func, arg, flag, EV_WAKEUP, &ep, ap); 449 va_end(ap); 450 if (error) 451 return (error); 452 453 mtx_lock(&g_eventlock); 454 while (!(ep->flag & EV_DONE)) 455 msleep(ep, &g_eventlock, PRIBIO, "g_waitfor_event", 0); 456 if (ep->flag & EV_CANCELED) 457 error = EAGAIN; 458 mtx_unlock(&g_eventlock); 459 460 g_free(ep); 461 return (error); 462 } 463 464 void 465 g_event_init(void) 466 { 467 468 mtx_init(&g_eventlock, "GEOM orphanage", NULL, MTX_DEF); 469 } 470