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 /* 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 if (ep->flag & EV_INPROGRESS) { 259 mtx_unlock(&g_eventlock); 260 return (1); 261 } 262 ep->flag |= EV_INPROGRESS; 263 mtx_unlock(&g_eventlock); 264 g_topology_assert(); 265 ep->func(ep->arg, 0); 266 g_topology_assert(); 267 mtx_lock(&g_eventlock); 268 TSRELEASE("GEOM events"); 269 TAILQ_REMOVE(&g_events, ep, events); 270 ep->flag &= ~EV_INPROGRESS; 271 if (ep->flag & EV_WAKEUP) { 272 ep->flag |= EV_DONE; 273 mtx_unlock(&g_eventlock); 274 wakeup(ep); 275 } else { 276 mtx_unlock(&g_eventlock); 277 g_free(ep); 278 } 279 return (1); 280 } 281 282 void 283 g_run_events() 284 { 285 286 for (;;) { 287 g_topology_lock(); 288 while (one_event()) 289 ; 290 mtx_assert(&g_eventlock, MA_OWNED); 291 if (g_wither_work) { 292 g_wither_work = 0; 293 mtx_unlock(&g_eventlock); 294 g_wither_washer(); 295 g_topology_unlock(); 296 } else { 297 g_topology_unlock(); 298 msleep(&g_wait_event, &g_eventlock, PRIBIO | PDROP, 299 "-", 0); 300 } 301 } 302 /* NOTREACHED */ 303 } 304 305 void 306 g_cancel_event(void *ref) 307 { 308 struct g_event *ep, *epn; 309 struct g_provider *pp; 310 u_int n; 311 312 mtx_lock(&g_eventlock); 313 TAILQ_FOREACH(pp, &g_doorstep, orphan) { 314 if (pp != ref) 315 continue; 316 TAILQ_REMOVE(&g_doorstep, pp, orphan); 317 break; 318 } 319 TAILQ_FOREACH_SAFE(ep, &g_events, events, epn) { 320 if (ep->flag & EV_INPROGRESS) 321 continue; 322 for (n = 0; n < G_N_EVENTREFS; n++) { 323 if (ep->ref[n] == NULL) 324 break; 325 if (ep->ref[n] != ref) 326 continue; 327 TSRELEASE("GEOM events"); 328 TAILQ_REMOVE(&g_events, ep, events); 329 ep->func(ep->arg, EV_CANCEL); 330 mtx_assert(&g_eventlock, MA_OWNED); 331 if (ep->flag & EV_WAKEUP) { 332 ep->flag |= (EV_DONE|EV_CANCELED); 333 wakeup(ep); 334 } else { 335 g_free(ep); 336 } 337 break; 338 } 339 } 340 if (TAILQ_EMPTY(&g_events)) 341 wakeup(&g_pending_events); 342 mtx_unlock(&g_eventlock); 343 } 344 345 static int 346 g_post_event_x(g_event_t *func, void *arg, int flag, int wuflag, struct g_event **epp, va_list ap) 347 { 348 struct g_event *ep; 349 void *p; 350 u_int n; 351 352 g_trace(G_T_TOPOLOGY, "g_post_event_x(%p, %p, %d, %d)", 353 func, arg, flag, wuflag); 354 KASSERT(wuflag == 0 || wuflag == EV_WAKEUP, 355 ("Wrong wuflag in g_post_event_x(0x%x)", wuflag)); 356 ep = g_malloc(sizeof *ep, flag | M_ZERO); 357 if (ep == NULL) 358 return (ENOMEM); 359 ep->flag = wuflag; 360 for (n = 0; n < G_N_EVENTREFS; n++) { 361 p = va_arg(ap, void *); 362 if (p == NULL) 363 break; 364 g_trace(G_T_TOPOLOGY, " ref %p", p); 365 ep->ref[n] = p; 366 } 367 KASSERT(p == NULL, ("Too many references to event")); 368 ep->func = func; 369 ep->arg = arg; 370 mtx_lock(&g_eventlock); 371 TSHOLD("GEOM events"); 372 TAILQ_INSERT_TAIL(&g_events, ep, events); 373 mtx_unlock(&g_eventlock); 374 wakeup(&g_wait_event); 375 if (epp != NULL) 376 *epp = ep; 377 curthread->td_pflags |= TDP_GEOM; 378 return (0); 379 } 380 381 int 382 g_post_event(g_event_t *func, void *arg, int flag, ...) 383 { 384 va_list ap; 385 int i; 386 387 KASSERT(flag == M_WAITOK || flag == M_NOWAIT, 388 ("Wrong flag to g_post_event")); 389 va_start(ap, flag); 390 i = g_post_event_x(func, arg, flag, 0, NULL, ap); 391 va_end(ap); 392 return (i); 393 } 394 395 void 396 g_do_wither() 397 { 398 399 mtx_lock(&g_eventlock); 400 g_wither_work = 1; 401 mtx_unlock(&g_eventlock); 402 wakeup(&g_wait_event); 403 } 404 405 /* 406 * XXX: It might actually be useful to call this function with topology held. 407 * XXX: This would ensure that the event gets created before anything else 408 * XXX: changes. At present all users have a handle on things in some other 409 * XXX: way, so this remains an XXX for now. 410 */ 411 412 int 413 g_waitfor_event(g_event_t *func, void *arg, int flag, ...) 414 { 415 va_list ap; 416 struct g_event *ep; 417 int error; 418 419 g_topology_assert_not(); 420 KASSERT(flag == M_WAITOK || flag == M_NOWAIT, 421 ("Wrong flag to g_post_event")); 422 va_start(ap, flag); 423 error = g_post_event_x(func, arg, flag, EV_WAKEUP, &ep, ap); 424 va_end(ap); 425 if (error) 426 return (error); 427 428 mtx_lock(&g_eventlock); 429 while (!(ep->flag & EV_DONE)) 430 msleep(ep, &g_eventlock, PRIBIO, "g_waitfor_event", hz); 431 if (ep->flag & EV_CANCELED) 432 error = EAGAIN; 433 mtx_unlock(&g_eventlock); 434 435 g_free(ep); 436 return (error); 437 } 438 439 void 440 g_event_init() 441 { 442 443 mtx_init(&g_eventlock, "GEOM orphanage", NULL, MTX_DEF); 444 } 445