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/time.h> 52 #include <geom/geom.h> 53 #include <geom/geom_int.h> 54 55 #include <machine/stdarg.h> 56 57 TAILQ_HEAD(event_tailq_head, g_event); 58 59 static struct event_tailq_head g_events = TAILQ_HEAD_INITIALIZER(g_events); 60 static u_int g_pending_events; 61 static TAILQ_HEAD(,g_provider) g_doorstep = TAILQ_HEAD_INITIALIZER(g_doorstep); 62 static struct mtx g_eventlock; 63 static int g_wither_work; 64 65 #define G_N_EVENTREFS 20 66 67 struct g_event { 68 TAILQ_ENTRY(g_event) events; 69 g_event_t *func; 70 void *arg; 71 int flag; 72 void *ref[G_N_EVENTREFS]; 73 }; 74 75 #define EV_DONE 0x80000 76 #define EV_WAKEUP 0x40000 77 #define EV_CANCELED 0x20000 78 #define EV_INPROGRESS 0x10000 79 80 void 81 g_waitidle(struct thread *td) 82 { 83 84 g_topology_assert_not(); 85 86 mtx_lock(&g_eventlock); 87 TSWAIT("GEOM events"); 88 while (!TAILQ_EMPTY(&g_events)) 89 msleep(&g_pending_events, &g_eventlock, PPAUSE, 90 "g_waitidle", 0); 91 TSUNWAIT("GEOM events"); 92 mtx_unlock(&g_eventlock); 93 td->td_pflags &= ~TDP_GEOM; 94 } 95 96 static void 97 ast_geom(struct thread *td, int tda __unused) 98 { 99 /* 100 * If this thread tickled GEOM, we need to wait for the giggling to 101 * stop before we return to userland. 102 */ 103 g_waitidle(td); 104 } 105 106 static void 107 geom_event_init(void *arg __unused) 108 { 109 ast_register(TDA_GEOM, ASTR_ASTF_REQUIRED | ASTR_TDP | ASTR_KCLEAR, 110 TDP_GEOM, ast_geom); 111 } 112 SYSINIT(geom_event, SI_SUB_INTRINSIC, SI_ORDER_ANY, geom_event_init, NULL); 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 * 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 /* 210 * XXX: g_dev_orphan method does deferred destroying 211 * and it is possible, that other event could already 212 * call the orphan method. Check consumer's flags to 213 * do not schedule it twice. 214 */ 215 if (cp->flags & G_CF_ORPHAN) 216 continue; 217 cp->flags |= G_CF_ORPHAN; 218 cp->geom->orphan(cp); 219 } 220 if (LIST_EMPTY(&pp->consumers) && wf) 221 g_destroy_provider(pp); 222 else 223 pp->flags |= wf; 224 #ifdef notyet 225 cp = LIST_FIRST(&pp->consumers); 226 if (cp != NULL) 227 return; 228 if (pp->geom->flags & G_GEOM_WITHER) 229 g_destroy_provider(pp); 230 #endif 231 } 232 233 static int 234 one_event(void) 235 { 236 struct g_event *ep; 237 struct g_provider *pp; 238 239 g_topology_assert(); 240 mtx_lock(&g_eventlock); 241 pp = TAILQ_FIRST(&g_doorstep); 242 if (pp != NULL) { 243 G_VALID_PROVIDER(pp); 244 TAILQ_REMOVE(&g_doorstep, pp, orphan); 245 mtx_unlock(&g_eventlock); 246 g_orphan_register(pp); 247 return (1); 248 } 249 250 ep = TAILQ_FIRST(&g_events); 251 if (ep == NULL) { 252 wakeup(&g_pending_events); 253 return (0); 254 } 255 ep->flag |= EV_INPROGRESS; 256 mtx_unlock(&g_eventlock); 257 g_topology_assert(); 258 ep->func(ep->arg, 0); 259 g_topology_assert(); 260 mtx_lock(&g_eventlock); 261 TSRELEASE("GEOM events"); 262 TAILQ_REMOVE(&g_events, ep, events); 263 ep->flag &= ~EV_INPROGRESS; 264 if (ep->flag & EV_WAKEUP) { 265 ep->flag |= EV_DONE; 266 wakeup(ep); 267 mtx_unlock(&g_eventlock); 268 } else { 269 mtx_unlock(&g_eventlock); 270 g_free(ep); 271 } 272 return (1); 273 } 274 275 void 276 g_run_events(void) 277 { 278 279 for (;;) { 280 g_topology_lock(); 281 while (one_event()) 282 ; 283 mtx_assert(&g_eventlock, MA_OWNED); 284 if (g_wither_work) { 285 g_wither_work = 0; 286 mtx_unlock(&g_eventlock); 287 g_wither_washer(); 288 g_topology_unlock(); 289 } else { 290 g_topology_unlock(); 291 msleep(&g_wait_event, &g_eventlock, PRIBIO | PDROP, 292 "-", 0); 293 } 294 } 295 /* NOTREACHED */ 296 } 297 298 void 299 g_cancel_event(void *ref) 300 { 301 struct g_event *ep, *epn; 302 struct g_provider *pp; 303 u_int n; 304 305 mtx_lock(&g_eventlock); 306 TAILQ_FOREACH(pp, &g_doorstep, orphan) { 307 if (pp != ref) 308 continue; 309 TAILQ_REMOVE(&g_doorstep, pp, orphan); 310 break; 311 } 312 TAILQ_FOREACH_SAFE(ep, &g_events, events, epn) { 313 if (ep->flag & EV_INPROGRESS) 314 continue; 315 for (n = 0; n < G_N_EVENTREFS; n++) { 316 if (ep->ref[n] == NULL) 317 break; 318 if (ep->ref[n] != ref) 319 continue; 320 TSRELEASE("GEOM events"); 321 TAILQ_REMOVE(&g_events, ep, events); 322 ep->func(ep->arg, EV_CANCEL); 323 mtx_assert(&g_eventlock, MA_OWNED); 324 if (ep->flag & EV_WAKEUP) { 325 ep->flag |= (EV_DONE|EV_CANCELED); 326 wakeup(ep); 327 } else { 328 g_free(ep); 329 } 330 break; 331 } 332 } 333 if (TAILQ_EMPTY(&g_events)) 334 wakeup(&g_pending_events); 335 mtx_unlock(&g_eventlock); 336 } 337 338 struct g_event * 339 g_alloc_event(int flag) 340 { 341 KASSERT(flag == M_WAITOK || flag == M_NOWAIT, 342 ("Wrong flag to g_alloc_event")); 343 344 return (g_malloc(sizeof(struct g_event), flag | M_ZERO)); 345 } 346 347 static void 348 g_post_event_ep_va(g_event_t *func, void *arg, int wuflag, 349 struct g_event *ep, va_list ap) 350 { 351 void *p; 352 u_int n; 353 354 ep->flag = wuflag; 355 for (n = 0; n < G_N_EVENTREFS; n++) { 356 p = va_arg(ap, void *); 357 if (p == NULL) 358 break; 359 g_trace(G_T_TOPOLOGY, " ref %p", p); 360 ep->ref[n] = p; 361 } 362 KASSERT(p == NULL, ("Too many references to event")); 363 ep->func = func; 364 ep->arg = arg; 365 mtx_lock(&g_eventlock); 366 TSHOLD("GEOM events"); 367 TAILQ_INSERT_TAIL(&g_events, ep, events); 368 mtx_unlock(&g_eventlock); 369 wakeup(&g_wait_event); 370 curthread->td_pflags |= TDP_GEOM; 371 ast_sched(curthread, TDA_GEOM); 372 } 373 374 void 375 g_post_event_ep(g_event_t *func, void *arg, struct g_event *ep, ...) 376 { 377 va_list ap; 378 379 va_start(ap, ep); 380 g_post_event_ep_va(func, arg, 0, ep, ap); 381 va_end(ap); 382 } 383 384 385 static int 386 g_post_event_x(g_event_t *func, void *arg, int flag, int wuflag, struct g_event **epp, va_list ap) 387 { 388 struct g_event *ep; 389 390 g_trace(G_T_TOPOLOGY, "g_post_event_x(%p, %p, %d, %d)", 391 func, arg, flag, wuflag); 392 KASSERT(wuflag == 0 || wuflag == EV_WAKEUP, 393 ("Wrong wuflag in g_post_event_x(0x%x)", wuflag)); 394 ep = g_alloc_event(flag); 395 if (ep == NULL) 396 return (ENOMEM); 397 if (epp != NULL) 398 *epp = ep; 399 g_post_event_ep_va(func, arg, wuflag, ep, ap); 400 return (0); 401 } 402 403 int 404 g_post_event(g_event_t *func, void *arg, int flag, ...) 405 { 406 va_list ap; 407 int i; 408 409 KASSERT(flag == M_WAITOK || flag == M_NOWAIT, 410 ("Wrong flag to g_post_event")); 411 va_start(ap, flag); 412 i = g_post_event_x(func, arg, flag, 0, NULL, ap); 413 va_end(ap); 414 return (i); 415 } 416 417 void 418 g_do_wither(void) 419 { 420 421 mtx_lock(&g_eventlock); 422 g_wither_work = 1; 423 mtx_unlock(&g_eventlock); 424 wakeup(&g_wait_event); 425 } 426 427 /* 428 * XXX: It might actually be useful to call this function with topology held. 429 * XXX: This would ensure that the event gets created before anything else 430 * XXX: changes. At present all users have a handle on things in some other 431 * XXX: way, so this remains an XXX for now. 432 */ 433 434 int 435 g_waitfor_event(g_event_t *func, void *arg, int flag, ...) 436 { 437 va_list ap; 438 struct g_event *ep; 439 int error; 440 441 g_topology_assert_not(); 442 KASSERT(flag == M_WAITOK || flag == M_NOWAIT, 443 ("Wrong flag to g_post_event")); 444 va_start(ap, flag); 445 error = g_post_event_x(func, arg, flag, EV_WAKEUP, &ep, ap); 446 va_end(ap); 447 if (error) 448 return (error); 449 450 mtx_lock(&g_eventlock); 451 while (!(ep->flag & EV_DONE)) 452 msleep(ep, &g_eventlock, PRIBIO, "g_waitfor_event", 0); 453 if (ep->flag & EV_CANCELED) 454 error = EAGAIN; 455 mtx_unlock(&g_eventlock); 456 457 g_free(ep); 458 return (error); 459 } 460 461 void 462 g_event_init(void) 463 { 464 465 mtx_init(&g_eventlock, "GEOM orphanage", NULL, MTX_DEF); 466 } 467