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