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", hz/5); 94 TSUNWAIT("GEOM events"); 95 mtx_unlock(&g_eventlock); 96 curthread->td_pflags &= ~TDP_GEOM; 97 } 98 99 #if 0 100 void 101 g_waitidlelock(void) 102 { 103 104 g_topology_assert(); 105 mtx_lock(&g_eventlock); 106 while (!TAILQ_EMPTY(&g_events)) { 107 g_topology_unlock(); 108 msleep(&g_pending_events, &g_eventlock, PPAUSE, 109 "g_waitidlel", hz/5); 110 g_topology_lock(); 111 } 112 mtx_unlock(&g_eventlock); 113 } 114 #endif 115 116 struct g_attrchanged_args { 117 struct g_provider *pp; 118 const char *attr; 119 }; 120 121 static void 122 g_attr_changed_event(void *arg, int flag) 123 { 124 struct g_attrchanged_args *args; 125 struct g_provider *pp; 126 struct g_consumer *cp; 127 struct g_consumer *next_cp; 128 129 args = arg; 130 pp = args->pp; 131 132 g_topology_assert(); 133 if (flag != EV_CANCEL && g_shutdown == 0) { 134 /* 135 * Tell all consumers of the change. 136 */ 137 LIST_FOREACH_SAFE(cp, &pp->consumers, consumers, next_cp) { 138 if (cp->geom->attrchanged != NULL) 139 cp->geom->attrchanged(cp, args->attr); 140 } 141 } 142 g_free(args); 143 } 144 145 int 146 g_attr_changed(struct g_provider *pp, const char *attr, int flag) 147 { 148 struct g_attrchanged_args *args; 149 int error; 150 151 args = g_malloc(sizeof *args, flag); 152 if (args == NULL) 153 return (ENOMEM); 154 args->pp = pp; 155 args->attr = attr; 156 error = g_post_event(g_attr_changed_event, args, flag, pp, NULL); 157 if (error != 0) 158 g_free(args); 159 return (error); 160 } 161 162 void 163 g_orphan_provider(struct g_provider *pp, int error) 164 { 165 166 /* G_VALID_PROVIDER(pp) We likely lack topology lock */ 167 g_trace(G_T_TOPOLOGY, "g_orphan_provider(%p(%s), %d)", 168 pp, pp->name, error); 169 KASSERT(error != 0, 170 ("g_orphan_provider(%p(%s), 0) error must be non-zero\n", 171 pp, pp->name)); 172 173 pp->error = error; 174 mtx_lock(&g_eventlock); 175 KASSERT(!(pp->flags & G_PF_ORPHAN), 176 ("g_orphan_provider(%p(%s)), already an orphan", pp, pp->name)); 177 pp->flags |= G_PF_ORPHAN; 178 TAILQ_INSERT_TAIL(&g_doorstep, pp, orphan); 179 mtx_unlock(&g_eventlock); 180 wakeup(&g_wait_event); 181 } 182 183 /* 184 * This function is called once on each provider which the event handler 185 * finds on its g_doorstep. 186 */ 187 188 static void 189 g_orphan_register(struct g_provider *pp) 190 { 191 struct g_consumer *cp, *cp2; 192 int wf; 193 194 g_topology_assert(); 195 G_VALID_PROVIDER(pp); 196 g_trace(G_T_TOPOLOGY, "g_orphan_register(%s)", pp->name); 197 198 g_cancel_event(pp); 199 200 wf = pp->flags & G_PF_WITHER; 201 pp->flags &= ~G_PF_WITHER; 202 203 /* 204 * Tell all consumers the bad news. 205 * Don't be surprised if they self-destruct. 206 */ 207 LIST_FOREACH_SAFE(cp, &pp->consumers, consumers, cp2) { 208 KASSERT(cp->geom->orphan != NULL, 209 ("geom %s has no orphan, class %s", 210 cp->geom->name, cp->geom->class->name)); 211 /* 212 * XXX: g_dev_orphan method does deferred destroying 213 * and it is possible, that other event could already 214 * call the orphan method. Check consumer's flags to 215 * do not schedule it twice. 216 */ 217 if (cp->flags & G_CF_ORPHAN) 218 continue; 219 cp->flags |= G_CF_ORPHAN; 220 cp->geom->orphan(cp); 221 } 222 if (LIST_EMPTY(&pp->consumers) && wf) 223 g_destroy_provider(pp); 224 else 225 pp->flags |= wf; 226 #ifdef notyet 227 cp = LIST_FIRST(&pp->consumers); 228 if (cp != NULL) 229 return; 230 if (pp->geom->flags & G_GEOM_WITHER) 231 g_destroy_provider(pp); 232 #endif 233 } 234 235 static int 236 one_event(void) 237 { 238 struct g_event *ep; 239 struct g_provider *pp; 240 241 g_topology_assert(); 242 mtx_lock(&g_eventlock); 243 pp = TAILQ_FIRST(&g_doorstep); 244 if (pp != NULL) { 245 G_VALID_PROVIDER(pp); 246 TAILQ_REMOVE(&g_doorstep, pp, orphan); 247 mtx_unlock(&g_eventlock); 248 g_orphan_register(pp); 249 return (1); 250 } 251 252 ep = TAILQ_FIRST(&g_events); 253 if (ep == NULL) { 254 wakeup(&g_pending_events); 255 return (0); 256 } 257 if (ep->flag & EV_INPROGRESS) { 258 mtx_unlock(&g_eventlock); 259 return (1); 260 } 261 ep->flag |= EV_INPROGRESS; 262 mtx_unlock(&g_eventlock); 263 g_topology_assert(); 264 ep->func(ep->arg, 0); 265 g_topology_assert(); 266 mtx_lock(&g_eventlock); 267 TSRELEASE("GEOM events"); 268 TAILQ_REMOVE(&g_events, ep, events); 269 ep->flag &= ~EV_INPROGRESS; 270 if (ep->flag & EV_WAKEUP) { 271 ep->flag |= EV_DONE; 272 mtx_unlock(&g_eventlock); 273 wakeup(ep); 274 } else { 275 mtx_unlock(&g_eventlock); 276 g_free(ep); 277 } 278 return (1); 279 } 280 281 void 282 g_run_events() 283 { 284 285 for (;;) { 286 g_topology_lock(); 287 while (one_event()) 288 ; 289 mtx_assert(&g_eventlock, MA_OWNED); 290 if (g_wither_work) { 291 g_wither_work = 0; 292 mtx_unlock(&g_eventlock); 293 g_wither_washer(); 294 g_topology_unlock(); 295 } else { 296 g_topology_unlock(); 297 msleep(&g_wait_event, &g_eventlock, PRIBIO | PDROP, 298 "-", 0); 299 } 300 } 301 /* NOTREACHED */ 302 } 303 304 void 305 g_cancel_event(void *ref) 306 { 307 struct g_event *ep, *epn; 308 struct g_provider *pp; 309 u_int n; 310 311 mtx_lock(&g_eventlock); 312 TAILQ_FOREACH(pp, &g_doorstep, orphan) { 313 if (pp != ref) 314 continue; 315 TAILQ_REMOVE(&g_doorstep, pp, orphan); 316 break; 317 } 318 TAILQ_FOREACH_SAFE(ep, &g_events, events, epn) { 319 if (ep->flag & EV_INPROGRESS) 320 continue; 321 for (n = 0; n < G_N_EVENTREFS; n++) { 322 if (ep->ref[n] == NULL) 323 break; 324 if (ep->ref[n] != ref) 325 continue; 326 TSRELEASE("GEOM events"); 327 TAILQ_REMOVE(&g_events, ep, events); 328 ep->func(ep->arg, EV_CANCEL); 329 mtx_assert(&g_eventlock, MA_OWNED); 330 if (ep->flag & EV_WAKEUP) { 331 ep->flag |= (EV_DONE|EV_CANCELED); 332 wakeup(ep); 333 } else { 334 g_free(ep); 335 } 336 break; 337 } 338 } 339 if (TAILQ_EMPTY(&g_events)) 340 wakeup(&g_pending_events); 341 mtx_unlock(&g_eventlock); 342 } 343 344 static int 345 g_post_event_x(g_event_t *func, void *arg, int flag, int wuflag, struct g_event **epp, va_list ap) 346 { 347 struct g_event *ep; 348 void *p; 349 u_int n; 350 351 g_trace(G_T_TOPOLOGY, "g_post_event_x(%p, %p, %d, %d)", 352 func, arg, flag, wuflag); 353 KASSERT(wuflag == 0 || wuflag == EV_WAKEUP, 354 ("Wrong wuflag in g_post_event_x(0x%x)", wuflag)); 355 ep = g_malloc(sizeof *ep, flag | M_ZERO); 356 if (ep == NULL) 357 return (ENOMEM); 358 ep->flag = wuflag; 359 for (n = 0; n < G_N_EVENTREFS; n++) { 360 p = va_arg(ap, void *); 361 if (p == NULL) 362 break; 363 g_trace(G_T_TOPOLOGY, " ref %p", p); 364 ep->ref[n] = p; 365 } 366 KASSERT(p == NULL, ("Too many references to event")); 367 ep->func = func; 368 ep->arg = arg; 369 mtx_lock(&g_eventlock); 370 TSHOLD("GEOM events"); 371 TAILQ_INSERT_TAIL(&g_events, ep, events); 372 mtx_unlock(&g_eventlock); 373 wakeup(&g_wait_event); 374 if (epp != NULL) 375 *epp = ep; 376 curthread->td_pflags |= TDP_GEOM; 377 thread_lock(curthread); 378 curthread->td_flags |= TDF_ASTPENDING; 379 thread_unlock(curthread); 380 return (0); 381 } 382 383 int 384 g_post_event(g_event_t *func, void *arg, int flag, ...) 385 { 386 va_list ap; 387 int i; 388 389 KASSERT(flag == M_WAITOK || flag == M_NOWAIT, 390 ("Wrong flag to g_post_event")); 391 va_start(ap, flag); 392 i = g_post_event_x(func, arg, flag, 0, NULL, ap); 393 va_end(ap); 394 return (i); 395 } 396 397 void 398 g_do_wither() 399 { 400 401 mtx_lock(&g_eventlock); 402 g_wither_work = 1; 403 mtx_unlock(&g_eventlock); 404 wakeup(&g_wait_event); 405 } 406 407 /* 408 * XXX: It might actually be useful to call this function with topology held. 409 * XXX: This would ensure that the event gets created before anything else 410 * XXX: changes. At present all users have a handle on things in some other 411 * XXX: way, so this remains an XXX for now. 412 */ 413 414 int 415 g_waitfor_event(g_event_t *func, void *arg, int flag, ...) 416 { 417 va_list ap; 418 struct g_event *ep; 419 int error; 420 421 g_topology_assert_not(); 422 KASSERT(flag == M_WAITOK || flag == M_NOWAIT, 423 ("Wrong flag to g_post_event")); 424 va_start(ap, flag); 425 error = g_post_event_x(func, arg, flag, EV_WAKEUP, &ep, ap); 426 va_end(ap); 427 if (error) 428 return (error); 429 430 mtx_lock(&g_eventlock); 431 while (!(ep->flag & EV_DONE)) 432 msleep(ep, &g_eventlock, PRIBIO, "g_waitfor_event", hz); 433 if (ep->flag & EV_CANCELED) 434 error = EAGAIN; 435 mtx_unlock(&g_eventlock); 436 437 g_free(ep); 438 return (error); 439 } 440 441 void 442 g_event_init() 443 { 444 445 mtx_init(&g_eventlock, "GEOM orphanage", NULL, MTX_DEF); 446 } 447