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 80 void 81 g_waitidle(void) 82 { 83 84 g_topology_assert_not(); 85 mtx_assert(&Giant, MA_NOTOWNED); 86 87 mtx_lock(&g_eventlock); 88 while (!TAILQ_EMPTY(&g_events)) 89 msleep(&g_pending_events, &g_eventlock, PPAUSE, 90 "g_waitidle", hz/5); 91 mtx_unlock(&g_eventlock); 92 curthread->td_pflags &= ~TDP_GEOM; 93 } 94 95 #if 0 96 void 97 g_waitidlelock(void) 98 { 99 100 g_topology_assert(); 101 mtx_lock(&g_eventlock); 102 while (!TAILQ_EMPTY(&g_events)) { 103 g_topology_unlock(); 104 msleep(&g_pending_events, &g_eventlock, PPAUSE, 105 "g_waitidlel", hz/5); 106 g_topology_lock(); 107 } 108 mtx_unlock(&g_eventlock); 109 } 110 #endif 111 112 void 113 g_orphan_provider(struct g_provider *pp, int error) 114 { 115 116 /* G_VALID_PROVIDER(pp) We likely lack topology lock */ 117 g_trace(G_T_TOPOLOGY, "g_orphan_provider(%p(%s), %d)", 118 pp, pp->name, error); 119 KASSERT(error != 0, 120 ("g_orphan_provider(%p(%s), 0) error must be non-zero\n", 121 pp, pp->name)); 122 123 pp->error = error; 124 mtx_lock(&g_eventlock); 125 KASSERT(!(pp->flags & G_PF_ORPHAN), 126 ("g_orphan_provider(%p(%s)), already an orphan", pp, pp->name)); 127 pp->flags |= G_PF_ORPHAN; 128 TAILQ_INSERT_TAIL(&g_doorstep, pp, orphan); 129 mtx_unlock(&g_eventlock); 130 wakeup(&g_wait_event); 131 } 132 133 /* 134 * This function is called once on each provider which the event handler 135 * finds on its g_doorstep. 136 */ 137 138 static void 139 g_orphan_register(struct g_provider *pp) 140 { 141 struct g_consumer *cp, *cp2; 142 int wf; 143 144 g_topology_assert(); 145 G_VALID_PROVIDER(pp); 146 g_trace(G_T_TOPOLOGY, "g_orphan_register(%s)", pp->name); 147 148 g_cancel_event(pp); 149 150 wf = pp->flags & G_PF_WITHER; 151 pp->flags &= ~G_PF_WITHER; 152 153 /* 154 * Tell all consumers the bad news. 155 * Don't be surprised if they self-destruct. 156 */ 157 cp = LIST_FIRST(&pp->consumers); 158 while (cp != NULL) { 159 cp2 = LIST_NEXT(cp, consumers); 160 KASSERT(cp->geom->orphan != NULL, 161 ("geom %s has no orphan, class %s", 162 cp->geom->name, cp->geom->class->name)); 163 cp->geom->orphan(cp); 164 cp = cp2; 165 } 166 if (LIST_EMPTY(&pp->consumers) && wf) 167 g_destroy_provider(pp); 168 else 169 pp->flags |= wf; 170 #ifdef notyet 171 cp = LIST_FIRST(&pp->consumers); 172 if (cp != NULL) 173 return; 174 if (pp->geom->flags & G_GEOM_WITHER) 175 g_destroy_provider(pp); 176 #endif 177 } 178 179 static int 180 one_event(void) 181 { 182 struct g_event *ep; 183 struct g_provider *pp; 184 185 g_topology_lock(); 186 for (;;) { 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 } 196 mtx_unlock(&g_eventlock); 197 if (pp == NULL) 198 break; 199 g_orphan_register(pp); 200 } 201 mtx_lock(&g_eventlock); 202 ep = TAILQ_FIRST(&g_events); 203 if (ep == NULL) { 204 wakeup(&g_pending_events); 205 mtx_unlock(&g_eventlock); 206 g_topology_unlock(); 207 return (0); 208 } 209 mtx_unlock(&g_eventlock); 210 g_topology_assert(); 211 ep->func(ep->arg, 0); 212 g_topology_assert(); 213 mtx_lock(&g_eventlock); 214 TAILQ_REMOVE(&g_events, ep, events); 215 mtx_unlock(&g_eventlock); 216 if (ep->flag & EV_WAKEUP) { 217 ep->flag |= EV_DONE; 218 wakeup(ep); 219 } else { 220 g_free(ep); 221 } 222 g_topology_unlock(); 223 return (1); 224 } 225 226 void 227 g_run_events() 228 { 229 int i; 230 231 while (one_event()) 232 ; 233 g_topology_lock(); 234 i = g_wither_work; 235 while (i) { 236 i = g_wither_washer(); 237 g_wither_work = i & 1; 238 i &= 2; 239 } 240 g_topology_unlock(); 241 } 242 243 void 244 g_cancel_event(void *ref) 245 { 246 struct g_event *ep, *epn; 247 struct g_provider *pp; 248 u_int n; 249 250 mtx_lock(&g_eventlock); 251 TAILQ_FOREACH(pp, &g_doorstep, orphan) { 252 if (pp != ref) 253 continue; 254 TAILQ_REMOVE(&g_doorstep, pp, orphan); 255 break; 256 } 257 TAILQ_FOREACH_SAFE(ep, &g_events, events, epn) { 258 for (n = 0; n < G_N_EVENTREFS; n++) { 259 if (ep->ref[n] == NULL) 260 break; 261 if (ep->ref[n] != ref) 262 continue; 263 TAILQ_REMOVE(&g_events, ep, events); 264 ep->func(ep->arg, EV_CANCEL); 265 mtx_assert(&g_eventlock, MA_OWNED); 266 if (ep->flag & EV_WAKEUP) { 267 ep->flag |= (EV_DONE|EV_CANCELED); 268 wakeup(ep); 269 } else { 270 g_free(ep); 271 } 272 break; 273 } 274 } 275 if (TAILQ_EMPTY(&g_events)) 276 wakeup(&g_pending_events); 277 mtx_unlock(&g_eventlock); 278 } 279 280 static int 281 g_post_event_x(g_event_t *func, void *arg, int flag, int wuflag, struct g_event **epp, va_list ap) 282 { 283 struct g_event *ep; 284 void *p; 285 u_int n; 286 287 g_trace(G_T_TOPOLOGY, "g_post_event_x(%p, %p, %d, %d)", 288 func, arg, flag, wuflag); 289 KASSERT(wuflag == 0 || wuflag == EV_WAKEUP, 290 ("Wrong wuflag in g_post_event_x(0x%x)", wuflag)); 291 ep = g_malloc(sizeof *ep, flag | M_ZERO); 292 if (ep == NULL) 293 return (ENOMEM); 294 ep->flag = wuflag; 295 for (n = 0; n < G_N_EVENTREFS; n++) { 296 p = va_arg(ap, void *); 297 if (p == NULL) 298 break; 299 g_trace(G_T_TOPOLOGY, " ref %p", p); 300 ep->ref[n] = p; 301 } 302 KASSERT(p == NULL, ("Too many references to event")); 303 ep->func = func; 304 ep->arg = arg; 305 mtx_lock(&g_eventlock); 306 TAILQ_INSERT_TAIL(&g_events, ep, events); 307 mtx_unlock(&g_eventlock); 308 wakeup(&g_wait_event); 309 if (epp != NULL) 310 *epp = ep; 311 curthread->td_pflags |= TDP_GEOM; 312 return (0); 313 } 314 315 int 316 g_post_event(g_event_t *func, void *arg, int flag, ...) 317 { 318 va_list ap; 319 int i; 320 321 KASSERT(flag == M_WAITOK || flag == M_NOWAIT, 322 ("Wrong flag to g_post_event")); 323 va_start(ap, flag); 324 i = g_post_event_x(func, arg, flag, 0, NULL, ap); 325 va_end(ap); 326 return (i); 327 } 328 329 void 330 g_do_wither() { 331 332 g_wither_work = 1; 333 wakeup(&g_wait_event); 334 } 335 336 /* 337 * XXX: It might actually be useful to call this function with topology held. 338 * XXX: This would ensure that the event gets created before anything else 339 * XXX: changes. At present all users have a handle on things in some other 340 * XXX: way, so this remains an XXX for now. 341 */ 342 343 int 344 g_waitfor_event(g_event_t *func, void *arg, int flag, ...) 345 { 346 va_list ap; 347 struct g_event *ep; 348 int error; 349 350 g_topology_assert_not(); 351 KASSERT(flag == M_WAITOK || flag == M_NOWAIT, 352 ("Wrong flag to g_post_event")); 353 va_start(ap, flag); 354 error = g_post_event_x(func, arg, flag, EV_WAKEUP, &ep, ap); 355 va_end(ap); 356 if (error) 357 return (error); 358 do 359 tsleep(ep, PRIBIO, "g_waitfor_event", hz); 360 while (!(ep->flag & EV_DONE)); 361 if (ep->flag & EV_CANCELED) 362 error = EAGAIN; 363 g_free(ep); 364 return (error); 365 } 366 367 void 368 g_event_init() 369 { 370 371 mtx_init(&g_eventlock, "GEOM orphanage", NULL, MTX_DEF); 372 } 373