1193326Sed/*- 2193326Sed * SPDX-License-Identifier: BSD-3-Clause 3193326Sed * 4193326Sed * Copyright (c) 2002 Poul-Henning Kamp 5193326Sed * Copyright (c) 2002 Networks Associates Technology, Inc. 6193326Sed * All rights reserved. 7193326Sed * 8193326Sed * This software was developed for the FreeBSD Project by Poul-Henning Kamp 9193326Sed * and NAI Labs, the Security Research Division of Network Associates, Inc. 10193326Sed * under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the 11193326Sed * DARPA CHATS research program. 12193326Sed * 13193326Sed * Redistribution and use in source and binary forms, with or without 14193326Sed * modification, are permitted provided that the following conditions 15193326Sed * are met: 16193326Sed * 1. Redistributions of source code must retain the above copyright 17193326Sed * notice, this list of conditions and the following disclaimer. 18193326Sed * 2. Redistributions in binary form must reproduce the above copyright 19234353Sdim * notice, this list of conditions and the following disclaimer in the 20249423Sdim * documentation and/or other materials provided with the distribution. 21234353Sdim * 3. The names of the authors may not be used to endorse or promote 22193326Sed * products derived from this software without specific prior written 23193326Sed * permission. 24198893Srdivacky * 25198893Srdivacky * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 26234353Sdim * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 27193326Sed * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 28226633Sdim * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 29226633Sdim * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 30249423Sdim * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 31198893Srdivacky * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 32234353Sdim * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 33234353Sdim * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 34193326Sed * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 35204643Srdivacky * SUCH DAMAGE. 36204643Srdivacky */ 37204643Srdivacky 38234353Sdim/* 39234353Sdim * XXX: How do we in general know that objects referenced in events 40193326Sed * have not been destroyed before we get around to handle the event ? 41243830Sdim */ 42199482Srdivacky 43199482Srdivacky#include <sys/param.h> 44193326Sed#include <sys/malloc.h> 45204643Srdivacky#include <sys/systm.h> 46204643Srdivacky#include <sys/kernel.h> 47204643Srdivacky#include <sys/lock.h> 48204643Srdivacky#include <sys/mutex.h> 49204643Srdivacky#include <sys/proc.h> 50234353Sdim#include <sys/errno.h> 51234353Sdim#include <sys/time.h> 52234353Sdim#include <geom/geom.h> 53193326Sed#include <geom/geom_int.h> 54193326Sed 55207632Srdivacky#include <machine/stdarg.h> 56193326Sed 57193326SedTAILQ_HEAD(event_tailq_head, g_event); 58 59static struct event_tailq_head g_events = TAILQ_HEAD_INITIALIZER(g_events); 60static u_int g_pending_events; 61static TAILQ_HEAD(,g_provider) g_doorstep = TAILQ_HEAD_INITIALIZER(g_doorstep); 62static struct mtx g_eventlock; 63static int g_wither_work; 64 65#define G_N_EVENTREFS 20 66 67struct 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 80void 81g_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 96static void 97ast_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 106static void 107geom_event_init(void *arg __unused) 108{ 109 ast_register(TDA_GEOM, ASTR_ASTF_REQUIRED | ASTR_TDP | ASTR_KCLEAR, 110 TDP_GEOM, ast_geom); 111} 112SYSINIT(geom_event, SI_SUB_INTRINSIC, SI_ORDER_ANY, geom_event_init, NULL); 113 114struct g_attrchanged_args { 115 struct g_provider *pp; 116 const char *attr; 117}; 118 119static void 120g_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 143int 144g_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 160void 161g_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 186static void 187g_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 233static int 234one_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 275void 276g_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 298void 299g_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 338struct g_event * 339g_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 347static void 348g_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 374void 375g_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 385static int 386g_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 403int 404g_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 417void 418g_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 434int 435g_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 461void 462g_event_init(void) 463{ 464 465 mtx_init(&g_eventlock, "GEOM orphanage", NULL, MTX_DEF); 466} 467