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 struct sx g_eventstall; 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_stall_events(void) 88 { 89 90 sx_xlock(&g_eventstall); 91 } 92 93 void 94 g_release_events(void) 95 { 96 97 sx_xunlock(&g_eventstall); 98 } 99 100 void 101 g_orphan_provider(struct g_provider *pp, int error) 102 { 103 104 g_trace(G_T_TOPOLOGY, "g_orphan_provider(%p(%s), %d)", 105 pp, pp->name, error); 106 KASSERT(error != 0, 107 ("g_orphan_provider(%p(%s), 0) error must be non-zero\n", 108 pp, pp->name)); 109 pp->error = error; 110 mtx_lock(&g_eventlock); 111 TAILQ_INSERT_TAIL(&g_doorstep, pp, orphan); 112 mtx_unlock(&g_eventlock); 113 wakeup(&g_wait_event); 114 } 115 116 /* 117 * This function is called once on each provider which the event handler 118 * finds on its g_doorstep. 119 */ 120 121 static void 122 g_orphan_register(struct g_provider *pp) 123 { 124 struct g_consumer *cp, *cp2; 125 126 g_trace(G_T_TOPOLOGY, "g_orphan_register(%s)", pp->name); 127 g_topology_assert(); 128 129 /* 130 * Tell all consumers the bad news. 131 * Don't be surprised if they self-destruct. 132 */ 133 cp = LIST_FIRST(&pp->consumers); 134 while (cp != NULL) { 135 cp2 = LIST_NEXT(cp, consumers); 136 KASSERT(cp->geom->orphan != NULL, 137 ("geom %s has no orphan, class %s", 138 cp->geom->name, cp->geom->class->name)); 139 cp->geom->orphan(cp); 140 cp = cp2; 141 } 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 sx_xlock(&g_eventstall); 158 g_topology_lock(); 159 for (;;) { 160 mtx_lock(&g_eventlock); 161 pp = TAILQ_FIRST(&g_doorstep); 162 if (pp != NULL) 163 TAILQ_REMOVE(&g_doorstep, pp, orphan); 164 mtx_unlock(&g_eventlock); 165 if (pp == NULL) 166 break; 167 g_orphan_register(pp); 168 } 169 mtx_lock(&g_eventlock); 170 ep = TAILQ_FIRST(&g_events); 171 if (ep == NULL) { 172 mtx_unlock(&g_eventlock); 173 g_topology_unlock(); 174 sx_xunlock(&g_eventstall); 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 sx_xunlock(&g_eventstall); 193 return (1); 194 } 195 196 void 197 g_run_events() 198 { 199 200 while (one_event()) 201 ; 202 } 203 204 void 205 g_cancel_event(void *ref) 206 { 207 struct g_event *ep, *epn; 208 struct g_provider *pp; 209 u_int n; 210 211 mtx_lock(&g_eventlock); 212 TAILQ_FOREACH(pp, &g_doorstep, orphan) { 213 if (pp != ref) 214 continue; 215 TAILQ_REMOVE(&g_doorstep, pp, orphan); 216 break; 217 } 218 for (ep = TAILQ_FIRST(&g_events); ep != NULL; ep = epn) { 219 epn = TAILQ_NEXT(ep, events); 220 for (n = 0; n < G_N_EVENTREFS; n++) { 221 if (ep->ref[n] == NULL) 222 break; 223 if (ep->ref[n] == ref) { 224 TAILQ_REMOVE(&g_events, ep, events); 225 ep->func(ep->arg, EV_CANCEL); 226 if (ep->flag & EV_WAKEUP) { 227 ep->flag |= EV_DONE; 228 ep->flag |= EV_CANCELED; 229 wakeup(ep); 230 } else { 231 g_free(ep); 232 } 233 break; 234 } 235 } 236 } 237 mtx_unlock(&g_eventlock); 238 } 239 240 static int 241 g_post_event_x(g_event_t *func, void *arg, int flag, struct g_event **epp, va_list ap) 242 { 243 struct g_event *ep; 244 void *p; 245 u_int n; 246 247 g_trace(G_T_TOPOLOGY, "g_post_event_x(%p, %p, %d", func, arg, flag); 248 ep = g_malloc(sizeof *ep, flag | M_ZERO); 249 if (ep == NULL) 250 return (ENOMEM); 251 ep->flag = flag; 252 for (n = 0; n < G_N_EVENTREFS; n++) { 253 p = va_arg(ap, void *); 254 if (p == NULL) 255 break; 256 g_trace(G_T_TOPOLOGY, " ref %p", p); 257 ep->ref[n++] = p; 258 } 259 KASSERT(p == NULL, ("Too many references to event")); 260 ep->func = func; 261 ep->arg = arg; 262 mtx_lock(&g_eventlock); 263 g_pending_events++; 264 TAILQ_INSERT_TAIL(&g_events, ep, events); 265 mtx_unlock(&g_eventlock); 266 wakeup(&g_wait_event); 267 if (epp != NULL) 268 *epp = ep; 269 return (0); 270 } 271 272 int 273 g_post_event(g_event_t *func, void *arg, int flag, ...) 274 { 275 va_list ap; 276 int i; 277 278 KASSERT(flag == M_WAITOK || flag == M_NOWAIT, 279 ("Wrong flag to g_post_event")); 280 va_start(ap, flag); 281 i = g_post_event_x(func, arg, flag, NULL, ap); 282 va_end(ap); 283 return (i); 284 } 285 286 287 /* 288 * XXX: It might actually be useful to call this function with topology held. 289 * XXX: This would ensure that the event gets created before anything else 290 * XXX: changes. At present all users have a handle on things in some other 291 * XXX: way, so this remains an XXX for now. 292 */ 293 294 int 295 g_waitfor_event(g_event_t *func, void *arg, int flag, ...) 296 { 297 va_list ap; 298 struct g_event *ep; 299 int error; 300 301 /* g_topology_assert_not(); */ 302 KASSERT(flag == M_WAITOK || flag == M_NOWAIT, 303 ("Wrong flag to g_post_event")); 304 va_start(ap, flag); 305 error = g_post_event_x(func, arg, flag | EV_WAKEUP, &ep, ap); 306 va_end(ap); 307 if (error) 308 return (error); 309 do 310 tsleep(ep, PRIBIO, "g_waitfor_event", hz); 311 while (!(ep->flag & EV_DONE)); 312 if (ep->flag & EV_CANCELED) 313 error = EAGAIN; 314 g_free(ep); 315 return (error); 316 } 317 318 void 319 g_event_init() 320 { 321 322 mtx_init(&g_eventlock, "GEOM orphanage", NULL, MTX_DEF); 323 sx_init(&g_eventstall, "GEOM event stalling"); 324 } 325