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_lock(); 187 for (;;) { 188 mtx_lock(&g_eventlock); 189 TAILQ_FOREACH(pp, &g_doorstep, orphan) { 190 if (pp->nstart == pp->nend) 191 break; 192 } 193 if (pp != NULL) { 194 G_VALID_PROVIDER(pp); 195 TAILQ_REMOVE(&g_doorstep, pp, orphan); 196 } 197 mtx_unlock(&g_eventlock); 198 if (pp == NULL) 199 break; 200 g_orphan_register(pp); 201 } 202 mtx_lock(&g_eventlock); 203 ep = TAILQ_FIRST(&g_events); 204 if (ep == NULL) { 205 wakeup(&g_pending_events); 206 mtx_unlock(&g_eventlock); 207 g_topology_unlock(); 208 return (0); 209 } 210 if (ep->flag & EV_INPROGRESS) { 211 mtx_unlock(&g_eventlock); 212 g_topology_unlock(); 213 return (1); 214 } 215 ep->flag |= EV_INPROGRESS; 216 mtx_unlock(&g_eventlock); 217 g_topology_assert(); 218 ep->func(ep->arg, 0); 219 g_topology_assert(); 220 mtx_lock(&g_eventlock); 221 TAILQ_REMOVE(&g_events, ep, events); 222 ep->flag &= ~EV_INPROGRESS; 223 mtx_unlock(&g_eventlock); 224 if (ep->flag & EV_WAKEUP) { 225 ep->flag |= EV_DONE; 226 wakeup(ep); 227 } else { 228 g_free(ep); 229 } 230 g_topology_unlock(); 231 return (1); 232 } 233 234 void 235 g_run_events() 236 { 237 int i; 238 239 while (one_event()) 240 ; 241 g_topology_lock(); 242 i = g_wither_work; 243 while (i) { 244 i = g_wither_washer(); 245 g_wither_work = i & 1; 246 i &= 2; 247 } 248 g_topology_unlock(); 249 } 250 251 void 252 g_cancel_event(void *ref) 253 { 254 struct g_event *ep, *epn; 255 struct g_provider *pp; 256 u_int n; 257 258 mtx_lock(&g_eventlock); 259 TAILQ_FOREACH(pp, &g_doorstep, orphan) { 260 if (pp != ref) 261 continue; 262 TAILQ_REMOVE(&g_doorstep, pp, orphan); 263 break; 264 } 265 TAILQ_FOREACH_SAFE(ep, &g_events, events, epn) { 266 if (ep->flag & EV_INPROGRESS) 267 continue; 268 for (n = 0; n < G_N_EVENTREFS; n++) { 269 if (ep->ref[n] == NULL) 270 break; 271 if (ep->ref[n] != ref) 272 continue; 273 TAILQ_REMOVE(&g_events, ep, events); 274 ep->func(ep->arg, EV_CANCEL); 275 mtx_assert(&g_eventlock, MA_OWNED); 276 if (ep->flag & EV_WAKEUP) { 277 ep->flag |= (EV_DONE|EV_CANCELED); 278 wakeup(ep); 279 } else { 280 g_free(ep); 281 } 282 break; 283 } 284 } 285 if (TAILQ_EMPTY(&g_events)) 286 wakeup(&g_pending_events); 287 mtx_unlock(&g_eventlock); 288 } 289 290 static int 291 g_post_event_x(g_event_t *func, void *arg, int flag, int wuflag, struct g_event **epp, va_list ap) 292 { 293 struct g_event *ep; 294 void *p; 295 u_int n; 296 297 g_trace(G_T_TOPOLOGY, "g_post_event_x(%p, %p, %d, %d)", 298 func, arg, flag, wuflag); 299 KASSERT(wuflag == 0 || wuflag == EV_WAKEUP, 300 ("Wrong wuflag in g_post_event_x(0x%x)", wuflag)); 301 ep = g_malloc(sizeof *ep, flag | M_ZERO); 302 if (ep == NULL) 303 return (ENOMEM); 304 ep->flag = wuflag; 305 for (n = 0; n < G_N_EVENTREFS; n++) { 306 p = va_arg(ap, void *); 307 if (p == NULL) 308 break; 309 g_trace(G_T_TOPOLOGY, " ref %p", p); 310 ep->ref[n] = p; 311 } 312 KASSERT(p == NULL, ("Too many references to event")); 313 ep->func = func; 314 ep->arg = arg; 315 mtx_lock(&g_eventlock); 316 TAILQ_INSERT_TAIL(&g_events, ep, events); 317 mtx_unlock(&g_eventlock); 318 wakeup(&g_wait_event); 319 if (epp != NULL) 320 *epp = ep; 321 curthread->td_pflags |= TDP_GEOM; 322 return (0); 323 } 324 325 int 326 g_post_event(g_event_t *func, void *arg, int flag, ...) 327 { 328 va_list ap; 329 int i; 330 331 KASSERT(flag == M_WAITOK || flag == M_NOWAIT, 332 ("Wrong flag to g_post_event")); 333 va_start(ap, flag); 334 i = g_post_event_x(func, arg, flag, 0, NULL, ap); 335 va_end(ap); 336 return (i); 337 } 338 339 void 340 g_do_wither() { 341 342 g_wither_work = 1; 343 wakeup(&g_wait_event); 344 } 345 346 /* 347 * XXX: It might actually be useful to call this function with topology held. 348 * XXX: This would ensure that the event gets created before anything else 349 * XXX: changes. At present all users have a handle on things in some other 350 * XXX: way, so this remains an XXX for now. 351 */ 352 353 int 354 g_waitfor_event(g_event_t *func, void *arg, int flag, ...) 355 { 356 va_list ap; 357 struct g_event *ep; 358 int error; 359 360 g_topology_assert_not(); 361 KASSERT(flag == M_WAITOK || flag == M_NOWAIT, 362 ("Wrong flag to g_post_event")); 363 va_start(ap, flag); 364 error = g_post_event_x(func, arg, flag, EV_WAKEUP, &ep, ap); 365 va_end(ap); 366 if (error) 367 return (error); 368 do 369 tsleep(ep, PRIBIO, "g_waitfor_event", hz); 370 while (!(ep->flag & EV_DONE)); 371 if (ep->flag & EV_CANCELED) 372 error = EAGAIN; 373 g_free(ep); 374 return (error); 375 } 376 377 void 378 g_event_init() 379 { 380 381 mtx_init(&g_eventlock, "GEOM orphanage", NULL, MTX_DEF); 382 } 383