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 <machine/stdarg.h> 51 #include <sys/errno.h> 52 #include <sys/time.h> 53 #include <geom/geom.h> 54 #include <geom/geom_int.h> 55 56 TAILQ_HEAD(event_tailq_head, g_event); 57 58 static struct event_tailq_head g_events = TAILQ_HEAD_INITIALIZER(g_events); 59 static u_int g_pending_events; 60 static TAILQ_HEAD(,g_provider) g_doorstep = TAILQ_HEAD_INITIALIZER(g_doorstep); 61 static struct mtx g_eventlock; 62 static int g_wither_work; 63 64 #define G_N_EVENTREFS 20 65 66 struct g_event { 67 TAILQ_ENTRY(g_event) events; 68 g_event_t *func; 69 void *arg; 70 int flag; 71 void *ref[G_N_EVENTREFS]; 72 }; 73 74 #define EV_DONE 0x80000 75 #define EV_WAKEUP 0x40000 76 #define EV_CANCELED 0x20000 77 78 void 79 g_waitidle(void) 80 { 81 82 while (g_pending_events) 83 tsleep(&g_pending_events, PPAUSE, "g_waitidle", hz/5); 84 } 85 86 void 87 g_orphan_provider(struct g_provider *pp, int error) 88 { 89 90 /* G_VALID_PROVIDER(pp) We likely lack topology lock */ 91 g_trace(G_T_TOPOLOGY, "g_orphan_provider(%p(%s), %d)", 92 pp, pp->name, error); 93 KASSERT(error != 0, 94 ("g_orphan_provider(%p(%s), 0) error must be non-zero\n", 95 pp, pp->name)); 96 97 pp->error = error; 98 mtx_lock(&g_eventlock); 99 KASSERT(!(pp->flags & G_PF_ORPHAN), 100 ("g_orphan_provider(%p(%s)), already an orphan", pp, pp->name)); 101 pp->flags |= G_PF_ORPHAN; 102 TAILQ_INSERT_TAIL(&g_doorstep, pp, orphan); 103 mtx_unlock(&g_eventlock); 104 wakeup(&g_wait_event); 105 } 106 107 /* 108 * This function is called once on each provider which the event handler 109 * finds on its g_doorstep. 110 */ 111 112 static void 113 g_orphan_register(struct g_provider *pp) 114 { 115 struct g_consumer *cp, *cp2; 116 int wf; 117 118 g_topology_assert(); 119 G_VALID_PROVIDER(pp); 120 g_trace(G_T_TOPOLOGY, "g_orphan_register(%s)", pp->name); 121 122 wf = pp->flags & G_PF_WITHER; 123 pp->flags &= ~G_PF_WITHER; 124 125 /* 126 * Tell all consumers the bad news. 127 * Don't be surprised if they self-destruct. 128 */ 129 cp = LIST_FIRST(&pp->consumers); 130 while (cp != NULL) { 131 cp2 = LIST_NEXT(cp, consumers); 132 KASSERT(cp->geom->orphan != NULL, 133 ("geom %s has no orphan, class %s", 134 cp->geom->name, cp->geom->class->name)); 135 cp->geom->orphan(cp); 136 cp = cp2; 137 } 138 if (LIST_EMPTY(&pp->consumers) && wf) 139 g_destroy_provider(pp); 140 else 141 pp->flags |= wf; 142 #ifdef notyet 143 cp = LIST_FIRST(&pp->consumers); 144 if (cp != NULL) 145 return; 146 if (pp->geom->flags & G_GEOM_WITHER) 147 g_destroy_provider(pp); 148 #endif 149 } 150 151 static int 152 one_event(void) 153 { 154 struct g_event *ep; 155 struct g_provider *pp; 156 157 g_topology_lock(); 158 for (;;) { 159 mtx_lock(&g_eventlock); 160 pp = TAILQ_FIRST(&g_doorstep); 161 if (pp != NULL) { 162 G_VALID_PROVIDER(pp); 163 TAILQ_REMOVE(&g_doorstep, pp, orphan); 164 } 165 mtx_unlock(&g_eventlock); 166 if (pp == NULL) 167 break; 168 g_orphan_register(pp); 169 } 170 mtx_lock(&g_eventlock); 171 ep = TAILQ_FIRST(&g_events); 172 if (ep == NULL) { 173 mtx_unlock(&g_eventlock); 174 g_topology_unlock(); 175 return (0); 176 } 177 TAILQ_REMOVE(&g_events, ep, events); 178 mtx_unlock(&g_eventlock); 179 g_topology_assert(); 180 ep->func(ep->arg, 0); 181 g_topology_assert(); 182 if (ep->flag & EV_WAKEUP) { 183 ep->flag |= EV_DONE; 184 wakeup(ep); 185 } else { 186 g_free(ep); 187 } 188 g_pending_events--; 189 if (g_pending_events == 0) 190 wakeup(&g_pending_events); 191 g_topology_unlock(); 192 return (1); 193 } 194 195 void 196 g_run_events() 197 { 198 int i; 199 200 while (one_event()) 201 ; 202 g_topology_lock(); 203 i = g_wither_work; 204 while (i) { 205 i = g_wither_washer(); 206 g_wither_work = i & 1; 207 i &= 2; 208 } 209 g_topology_unlock(); 210 } 211 212 void 213 g_cancel_event(void *ref) 214 { 215 struct g_event *ep, *epn; 216 struct g_provider *pp; 217 u_int n; 218 219 mtx_lock(&g_eventlock); 220 TAILQ_FOREACH(pp, &g_doorstep, orphan) { 221 if (pp != ref) 222 continue; 223 TAILQ_REMOVE(&g_doorstep, pp, orphan); 224 break; 225 } 226 for (ep = TAILQ_FIRST(&g_events); ep != NULL; ep = epn) { 227 epn = TAILQ_NEXT(ep, events); 228 for (n = 0; n < G_N_EVENTREFS; n++) { 229 if (ep->ref[n] == NULL) 230 break; 231 if (ep->ref[n] == ref) { 232 TAILQ_REMOVE(&g_events, ep, events); 233 ep->func(ep->arg, EV_CANCEL); 234 if (ep->flag & EV_WAKEUP) { 235 ep->flag |= EV_DONE; 236 ep->flag |= EV_CANCELED; 237 wakeup(ep); 238 } else { 239 g_free(ep); 240 } 241 if (--g_pending_events == 0) 242 wakeup(&g_pending_events); 243 break; 244 } 245 } 246 } 247 mtx_unlock(&g_eventlock); 248 } 249 250 static int 251 g_post_event_x(g_event_t *func, void *arg, int flag, int wuflag, struct g_event **epp, va_list ap) 252 { 253 struct g_event *ep; 254 void *p; 255 u_int n; 256 257 g_trace(G_T_TOPOLOGY, "g_post_event_x(%p, %p, %d, %d)", 258 func, arg, flag, wakeup); 259 KASSERT(wuflag == 0 || wuflag == EV_WAKEUP, 260 ("Wrong wuflag in g_post_event_x(0x%x)", wuflag)); 261 ep = g_malloc(sizeof *ep, flag | M_ZERO); 262 if (ep == NULL) 263 return (ENOMEM); 264 ep->flag = wuflag; 265 for (n = 0; n < G_N_EVENTREFS; n++) { 266 p = va_arg(ap, void *); 267 if (p == NULL) 268 break; 269 g_trace(G_T_TOPOLOGY, " ref %p", p); 270 ep->ref[n] = p; 271 } 272 KASSERT(p == NULL, ("Too many references to event")); 273 ep->func = func; 274 ep->arg = arg; 275 mtx_lock(&g_eventlock); 276 g_pending_events++; 277 TAILQ_INSERT_TAIL(&g_events, ep, events); 278 mtx_unlock(&g_eventlock); 279 wakeup(&g_wait_event); 280 if (epp != NULL) 281 *epp = ep; 282 return (0); 283 } 284 285 int 286 g_post_event(g_event_t *func, void *arg, int flag, ...) 287 { 288 va_list ap; 289 int i; 290 291 KASSERT(flag == M_WAITOK || flag == M_NOWAIT, 292 ("Wrong flag to g_post_event")); 293 va_start(ap, flag); 294 i = g_post_event_x(func, arg, flag, 0, NULL, ap); 295 va_end(ap); 296 return (i); 297 } 298 299 void 300 g_do_wither() { 301 302 g_wither_work = 1; 303 wakeup(&g_wait_event); 304 } 305 306 /* 307 * XXX: It might actually be useful to call this function with topology held. 308 * XXX: This would ensure that the event gets created before anything else 309 * XXX: changes. At present all users have a handle on things in some other 310 * XXX: way, so this remains an XXX for now. 311 */ 312 313 int 314 g_waitfor_event(g_event_t *func, void *arg, int flag, ...) 315 { 316 va_list ap; 317 struct g_event *ep; 318 int error; 319 320 g_topology_assert_not(); 321 KASSERT(flag == M_WAITOK || flag == M_NOWAIT, 322 ("Wrong flag to g_post_event")); 323 va_start(ap, flag); 324 error = g_post_event_x(func, arg, flag, EV_WAKEUP, &ep, ap); 325 va_end(ap); 326 if (error) 327 return (error); 328 do 329 tsleep(ep, PRIBIO, "g_waitfor_event", hz); 330 while (!(ep->flag & EV_DONE)); 331 if (ep->flag & EV_CANCELED) 332 error = EAGAIN; 333 g_free(ep); 334 return (error); 335 } 336 337 void 338 g_event_init() 339 { 340 341 mtx_init(&g_eventlock, "GEOM orphanage", NULL, MTX_DEF); 342 } 343