1 /*- 2 * Copyright (c) 2002 Poul-Henning Kamp 3 * Copyright (c) 2002 Networks Associates Technology, Inc. 4 * All rights reserved. 5 * 6 * This software was developed for the FreeBSD Project by Poul-Henning Kamp 7 * and NAI Labs, the Security Research Division of Network Associates, Inc. 8 * under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the 9 * DARPA CHATS research program. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 3. The names of the authors may not be used to endorse or promote 20 * products derived from this software without specific prior written 21 * permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 */ 35 36 /* 37 * XXX: How do we in general know that objects referenced in events 38 * have not been destroyed before we get around to handle the event ? 39 */ 40 41 #include <sys/cdefs.h> 42 __FBSDID("$FreeBSD$"); 43 44 #include <sys/param.h> 45 #include <sys/malloc.h> 46 #include <sys/systm.h> 47 #include <sys/kernel.h> 48 #include <sys/lock.h> 49 #include <sys/mutex.h> 50 #include <sys/proc.h> 51 #include <sys/errno.h> 52 #include <sys/time.h> 53 #include <geom/geom.h> 54 #include <geom/geom_int.h> 55 56 #include <machine/stdarg.h> 57 58 TAILQ_HEAD(event_tailq_head, g_event); 59 60 static struct event_tailq_head g_events = TAILQ_HEAD_INITIALIZER(g_events); 61 static u_int g_pending_events; 62 static TAILQ_HEAD(,g_provider) g_doorstep = TAILQ_HEAD_INITIALIZER(g_doorstep); 63 static struct mtx g_eventlock; 64 static int g_wither_work; 65 66 #define G_N_EVENTREFS 20 67 68 struct g_event { 69 TAILQ_ENTRY(g_event) events; 70 g_event_t *func; 71 void *arg; 72 int flag; 73 void *ref[G_N_EVENTREFS]; 74 }; 75 76 #define EV_DONE 0x80000 77 #define EV_WAKEUP 0x40000 78 #define EV_CANCELED 0x20000 79 #define EV_INPROGRESS 0x10000 80 81 void 82 g_waitidle(void) 83 { 84 85 g_topology_assert_not(); 86 mtx_assert(&Giant, MA_NOTOWNED); 87 88 mtx_lock(&g_eventlock); 89 while (!TAILQ_EMPTY(&g_events)) 90 msleep(&g_pending_events, &g_eventlock, PPAUSE, 91 "g_waitidle", hz/5); 92 mtx_unlock(&g_eventlock); 93 curthread->td_pflags &= ~TDP_GEOM; 94 } 95 96 #if 0 97 void 98 g_waitidlelock(void) 99 { 100 101 g_topology_assert(); 102 mtx_lock(&g_eventlock); 103 while (!TAILQ_EMPTY(&g_events)) { 104 g_topology_unlock(); 105 msleep(&g_pending_events, &g_eventlock, PPAUSE, 106 "g_waitidlel", hz/5); 107 g_topology_lock(); 108 } 109 mtx_unlock(&g_eventlock); 110 } 111 #endif 112 113 void 114 g_orphan_provider(struct g_provider *pp, int error) 115 { 116 117 /* G_VALID_PROVIDER(pp) We likely lack topology lock */ 118 g_trace(G_T_TOPOLOGY, "g_orphan_provider(%p(%s), %d)", 119 pp, pp->name, error); 120 KASSERT(error != 0, 121 ("g_orphan_provider(%p(%s), 0) error must be non-zero\n", 122 pp, pp->name)); 123 124 pp->error = error; 125 mtx_lock(&g_eventlock); 126 KASSERT(!(pp->flags & G_PF_ORPHAN), 127 ("g_orphan_provider(%p(%s)), already an orphan", pp, pp->name)); 128 pp->flags |= G_PF_ORPHAN; 129 TAILQ_INSERT_TAIL(&g_doorstep, pp, orphan); 130 mtx_unlock(&g_eventlock); 131 wakeup(&g_wait_event); 132 } 133 134 /* 135 * This function is called once on each provider which the event handler 136 * finds on its g_doorstep. 137 */ 138 139 static void 140 g_orphan_register(struct g_provider *pp) 141 { 142 struct g_consumer *cp, *cp2; 143 int wf; 144 145 g_topology_assert(); 146 G_VALID_PROVIDER(pp); 147 g_trace(G_T_TOPOLOGY, "g_orphan_register(%s)", pp->name); 148 149 g_cancel_event(pp); 150 151 wf = pp->flags & G_PF_WITHER; 152 pp->flags &= ~G_PF_WITHER; 153 154 /* 155 * Tell all consumers the bad news. 156 * Don't be surprised if they self-destruct. 157 */ 158 cp = LIST_FIRST(&pp->consumers); 159 while (cp != NULL) { 160 cp2 = LIST_NEXT(cp, consumers); 161 KASSERT(cp->geom->orphan != NULL, 162 ("geom %s has no orphan, class %s", 163 cp->geom->name, cp->geom->class->name)); 164 cp->geom->orphan(cp); 165 cp = cp2; 166 } 167 if (LIST_EMPTY(&pp->consumers) && wf) 168 g_destroy_provider(pp); 169 else 170 pp->flags |= wf; 171 #ifdef notyet 172 cp = LIST_FIRST(&pp->consumers); 173 if (cp != NULL) 174 return; 175 if (pp->geom->flags & G_GEOM_WITHER) 176 g_destroy_provider(pp); 177 #endif 178 } 179 180 static int 181 one_event(void) 182 { 183 struct g_event *ep; 184 struct g_provider *pp; 185 186 g_topology_assert(); 187 mtx_lock(&g_eventlock); 188 TAILQ_FOREACH(pp, &g_doorstep, orphan) { 189 if (pp->nstart == pp->nend) 190 break; 191 } 192 if (pp != NULL) { 193 G_VALID_PROVIDER(pp); 194 TAILQ_REMOVE(&g_doorstep, pp, orphan); 195 mtx_unlock(&g_eventlock); 196 g_orphan_register(pp); 197 return (1); 198 } 199 200 ep = TAILQ_FIRST(&g_events); 201 if (ep == NULL) { 202 wakeup(&g_pending_events); 203 return (0); 204 } 205 if (ep->flag & EV_INPROGRESS) { 206 mtx_unlock(&g_eventlock); 207 return (1); 208 } 209 ep->flag |= EV_INPROGRESS; 210 mtx_unlock(&g_eventlock); 211 g_topology_assert(); 212 ep->func(ep->arg, 0); 213 g_topology_assert(); 214 mtx_lock(&g_eventlock); 215 TAILQ_REMOVE(&g_events, ep, events); 216 ep->flag &= ~EV_INPROGRESS; 217 if (ep->flag & EV_WAKEUP) { 218 ep->flag |= EV_DONE; 219 mtx_unlock(&g_eventlock); 220 wakeup(ep); 221 } else { 222 mtx_unlock(&g_eventlock); 223 g_free(ep); 224 } 225 return (1); 226 } 227 228 void 229 g_run_events() 230 { 231 int i; 232 233 for (;;) { 234 g_topology_lock(); 235 while (one_event()) 236 ; 237 mtx_assert(&g_eventlock, MA_OWNED); 238 i = g_wither_work; 239 if (i) { 240 mtx_unlock(&g_eventlock); 241 while (i) { 242 i = g_wither_washer(); 243 g_wither_work = i & 1; 244 i &= 2; 245 } 246 g_topology_unlock(); 247 } else { 248 g_topology_unlock(); 249 msleep(&g_wait_event, &g_eventlock, PRIBIO | PDROP, 250 "-", 0); 251 } 252 } 253 /* NOTREACHED */ 254 } 255 256 void 257 g_cancel_event(void *ref) 258 { 259 struct g_event *ep, *epn; 260 struct g_provider *pp; 261 u_int n; 262 263 mtx_lock(&g_eventlock); 264 TAILQ_FOREACH(pp, &g_doorstep, orphan) { 265 if (pp != ref) 266 continue; 267 TAILQ_REMOVE(&g_doorstep, pp, orphan); 268 break; 269 } 270 TAILQ_FOREACH_SAFE(ep, &g_events, events, epn) { 271 if (ep->flag & EV_INPROGRESS) 272 continue; 273 for (n = 0; n < G_N_EVENTREFS; n++) { 274 if (ep->ref[n] == NULL) 275 break; 276 if (ep->ref[n] != ref) 277 continue; 278 TAILQ_REMOVE(&g_events, ep, events); 279 ep->func(ep->arg, EV_CANCEL); 280 mtx_assert(&g_eventlock, MA_OWNED); 281 if (ep->flag & EV_WAKEUP) { 282 ep->flag |= (EV_DONE|EV_CANCELED); 283 wakeup(ep); 284 } else { 285 g_free(ep); 286 } 287 break; 288 } 289 } 290 if (TAILQ_EMPTY(&g_events)) 291 wakeup(&g_pending_events); 292 mtx_unlock(&g_eventlock); 293 } 294 295 static int 296 g_post_event_x(g_event_t *func, void *arg, int flag, int wuflag, struct g_event **epp, va_list ap) 297 { 298 struct g_event *ep; 299 void *p; 300 u_int n; 301 302 g_trace(G_T_TOPOLOGY, "g_post_event_x(%p, %p, %d, %d)", 303 func, arg, flag, wuflag); 304 KASSERT(wuflag == 0 || wuflag == EV_WAKEUP, 305 ("Wrong wuflag in g_post_event_x(0x%x)", wuflag)); 306 ep = g_malloc(sizeof *ep, flag | M_ZERO); 307 if (ep == NULL) 308 return (ENOMEM); 309 ep->flag = wuflag; 310 for (n = 0; n < G_N_EVENTREFS; n++) { 311 p = va_arg(ap, void *); 312 if (p == NULL) 313 break; 314 g_trace(G_T_TOPOLOGY, " ref %p", p); 315 ep->ref[n] = p; 316 } 317 KASSERT(p == NULL, ("Too many references to event")); 318 ep->func = func; 319 ep->arg = arg; 320 mtx_lock(&g_eventlock); 321 TAILQ_INSERT_TAIL(&g_events, ep, events); 322 mtx_unlock(&g_eventlock); 323 wakeup(&g_wait_event); 324 if (epp != NULL) 325 *epp = ep; 326 curthread->td_pflags |= TDP_GEOM; 327 return (0); 328 } 329 330 int 331 g_post_event(g_event_t *func, void *arg, int flag, ...) 332 { 333 va_list ap; 334 int i; 335 336 KASSERT(flag == M_WAITOK || flag == M_NOWAIT, 337 ("Wrong flag to g_post_event")); 338 va_start(ap, flag); 339 i = g_post_event_x(func, arg, flag, 0, NULL, ap); 340 va_end(ap); 341 return (i); 342 } 343 344 void 345 g_do_wither() 346 { 347 348 mtx_lock(&g_eventlock); 349 g_wither_work = 1; 350 mtx_unlock(&g_eventlock); 351 wakeup(&g_wait_event); 352 } 353 354 /* 355 * XXX: It might actually be useful to call this function with topology held. 356 * XXX: This would ensure that the event gets created before anything else 357 * XXX: changes. At present all users have a handle on things in some other 358 * XXX: way, so this remains an XXX for now. 359 */ 360 361 int 362 g_waitfor_event(g_event_t *func, void *arg, int flag, ...) 363 { 364 va_list ap; 365 struct g_event *ep; 366 int error; 367 368 g_topology_assert_not(); 369 KASSERT(flag == M_WAITOK || flag == M_NOWAIT, 370 ("Wrong flag to g_post_event")); 371 va_start(ap, flag); 372 error = g_post_event_x(func, arg, flag, EV_WAKEUP, &ep, ap); 373 va_end(ap); 374 if (error) 375 return (error); 376 377 mtx_lock(&g_eventlock); 378 while (!(ep->flag & EV_DONE)) 379 msleep(ep, &g_eventlock, PRIBIO, "g_waitfor_event", hz); 380 if (ep->flag & EV_CANCELED) 381 error = EAGAIN; 382 mtx_unlock(&g_eventlock); 383 384 g_free(ep); 385 return (error); 386 } 387 388 void 389 g_event_init() 390 { 391 392 mtx_init(&g_eventlock, "GEOM orphanage", NULL, MTX_DEF); 393 } 394