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 while (g_pending_events) 88 tsleep(&g_pending_events, PPAUSE, "g_waitidle", hz/5); 89 curthread->td_pflags &= ~TDP_GEOM; 90 } 91 92 void 93 g_orphan_provider(struct g_provider *pp, int error) 94 { 95 96 /* G_VALID_PROVIDER(pp) We likely lack topology lock */ 97 g_trace(G_T_TOPOLOGY, "g_orphan_provider(%p(%s), %d)", 98 pp, pp->name, error); 99 KASSERT(error != 0, 100 ("g_orphan_provider(%p(%s), 0) error must be non-zero\n", 101 pp, pp->name)); 102 103 pp->error = error; 104 mtx_lock(&g_eventlock); 105 KASSERT(!(pp->flags & G_PF_ORPHAN), 106 ("g_orphan_provider(%p(%s)), already an orphan", pp, pp->name)); 107 pp->flags |= G_PF_ORPHAN; 108 TAILQ_INSERT_TAIL(&g_doorstep, pp, orphan); 109 mtx_unlock(&g_eventlock); 110 wakeup(&g_wait_event); 111 } 112 113 /* 114 * This function is called once on each provider which the event handler 115 * finds on its g_doorstep. 116 */ 117 118 static void 119 g_orphan_register(struct g_provider *pp) 120 { 121 struct g_consumer *cp, *cp2; 122 int wf; 123 124 g_topology_assert(); 125 G_VALID_PROVIDER(pp); 126 g_trace(G_T_TOPOLOGY, "g_orphan_register(%s)", pp->name); 127 128 wf = pp->flags & G_PF_WITHER; 129 pp->flags &= ~G_PF_WITHER; 130 131 /* 132 * Tell all consumers the bad news. 133 * Don't be surprised if they self-destruct. 134 */ 135 cp = LIST_FIRST(&pp->consumers); 136 while (cp != NULL) { 137 cp2 = LIST_NEXT(cp, consumers); 138 KASSERT(cp->geom->orphan != NULL, 139 ("geom %s has no orphan, class %s", 140 cp->geom->name, cp->geom->class->name)); 141 cp->geom->orphan(cp); 142 cp = cp2; 143 } 144 if (LIST_EMPTY(&pp->consumers) && wf) 145 g_destroy_provider(pp); 146 else 147 pp->flags |= wf; 148 #ifdef notyet 149 cp = LIST_FIRST(&pp->consumers); 150 if (cp != NULL) 151 return; 152 if (pp->geom->flags & G_GEOM_WITHER) 153 g_destroy_provider(pp); 154 #endif 155 } 156 157 static int 158 one_event(void) 159 { 160 struct g_event *ep; 161 struct g_provider *pp; 162 163 g_topology_lock(); 164 for (;;) { 165 mtx_lock(&g_eventlock); 166 pp = TAILQ_FIRST(&g_doorstep); 167 if (pp != NULL) { 168 G_VALID_PROVIDER(pp); 169 TAILQ_REMOVE(&g_doorstep, pp, orphan); 170 } 171 mtx_unlock(&g_eventlock); 172 if (pp == NULL) 173 break; 174 g_orphan_register(pp); 175 } 176 mtx_lock(&g_eventlock); 177 ep = TAILQ_FIRST(&g_events); 178 if (ep == NULL) { 179 mtx_unlock(&g_eventlock); 180 g_topology_unlock(); 181 return (0); 182 } 183 TAILQ_REMOVE(&g_events, ep, events); 184 mtx_unlock(&g_eventlock); 185 g_topology_assert(); 186 ep->func(ep->arg, 0); 187 g_topology_assert(); 188 if (ep->flag & EV_WAKEUP) { 189 ep->flag |= EV_DONE; 190 wakeup(ep); 191 } else { 192 g_free(ep); 193 } 194 g_pending_events--; 195 if (g_pending_events == 0) 196 wakeup(&g_pending_events); 197 g_topology_unlock(); 198 return (1); 199 } 200 201 void 202 g_run_events() 203 { 204 int i; 205 206 while (one_event()) 207 ; 208 g_topology_lock(); 209 i = g_wither_work; 210 while (i) { 211 i = g_wither_washer(); 212 g_wither_work = i & 1; 213 i &= 2; 214 } 215 g_topology_unlock(); 216 } 217 218 void 219 g_cancel_event(void *ref) 220 { 221 struct g_event *ep, *epn; 222 struct g_provider *pp; 223 u_int n; 224 225 mtx_lock(&g_eventlock); 226 TAILQ_FOREACH(pp, &g_doorstep, orphan) { 227 if (pp != ref) 228 continue; 229 TAILQ_REMOVE(&g_doorstep, pp, orphan); 230 break; 231 } 232 for (ep = TAILQ_FIRST(&g_events); ep != NULL; ep = epn) { 233 epn = TAILQ_NEXT(ep, events); 234 for (n = 0; n < G_N_EVENTREFS; n++) { 235 if (ep->ref[n] == NULL) 236 break; 237 if (ep->ref[n] == ref) { 238 TAILQ_REMOVE(&g_events, ep, events); 239 ep->func(ep->arg, EV_CANCEL); 240 if (ep->flag & EV_WAKEUP) { 241 ep->flag |= EV_DONE; 242 ep->flag |= EV_CANCELED; 243 wakeup(ep); 244 } else { 245 g_free(ep); 246 } 247 if (--g_pending_events == 0) 248 wakeup(&g_pending_events); 249 break; 250 } 251 } 252 } 253 mtx_unlock(&g_eventlock); 254 } 255 256 static int 257 g_post_event_x(g_event_t *func, void *arg, int flag, int wuflag, struct g_event **epp, va_list ap) 258 { 259 struct g_event *ep; 260 void *p; 261 u_int n; 262 263 g_trace(G_T_TOPOLOGY, "g_post_event_x(%p, %p, %d, %d)", 264 func, arg, flag, wakeup); 265 KASSERT(wuflag == 0 || wuflag == EV_WAKEUP, 266 ("Wrong wuflag in g_post_event_x(0x%x)", wuflag)); 267 ep = g_malloc(sizeof *ep, flag | M_ZERO); 268 if (ep == NULL) 269 return (ENOMEM); 270 ep->flag = wuflag; 271 for (n = 0; n < G_N_EVENTREFS; n++) { 272 p = va_arg(ap, void *); 273 if (p == NULL) 274 break; 275 g_trace(G_T_TOPOLOGY, " ref %p", p); 276 ep->ref[n] = p; 277 } 278 KASSERT(p == NULL, ("Too many references to event")); 279 ep->func = func; 280 ep->arg = arg; 281 mtx_lock(&g_eventlock); 282 g_pending_events++; 283 TAILQ_INSERT_TAIL(&g_events, ep, events); 284 mtx_unlock(&g_eventlock); 285 wakeup(&g_wait_event); 286 if (epp != NULL) 287 *epp = ep; 288 curthread->td_pflags |= TDP_GEOM; 289 return (0); 290 } 291 292 int 293 g_post_event(g_event_t *func, void *arg, int flag, ...) 294 { 295 va_list ap; 296 int i; 297 298 KASSERT(flag == M_WAITOK || flag == M_NOWAIT, 299 ("Wrong flag to g_post_event")); 300 va_start(ap, flag); 301 i = g_post_event_x(func, arg, flag, 0, NULL, ap); 302 va_end(ap); 303 return (i); 304 } 305 306 void 307 g_do_wither() { 308 309 g_wither_work = 1; 310 wakeup(&g_wait_event); 311 } 312 313 /* 314 * XXX: It might actually be useful to call this function with topology held. 315 * XXX: This would ensure that the event gets created before anything else 316 * XXX: changes. At present all users have a handle on things in some other 317 * XXX: way, so this remains an XXX for now. 318 */ 319 320 int 321 g_waitfor_event(g_event_t *func, void *arg, int flag, ...) 322 { 323 va_list ap; 324 struct g_event *ep; 325 int error; 326 327 g_topology_assert_not(); 328 KASSERT(flag == M_WAITOK || flag == M_NOWAIT, 329 ("Wrong flag to g_post_event")); 330 va_start(ap, flag); 331 error = g_post_event_x(func, arg, flag, EV_WAKEUP, &ep, ap); 332 va_end(ap); 333 if (error) 334 return (error); 335 do 336 tsleep(ep, PRIBIO, "g_waitfor_event", hz); 337 while (!(ep->flag & EV_DONE)); 338 if (ep->flag & EV_CANCELED) 339 error = EAGAIN; 340 g_free(ep); 341 return (error); 342 } 343 344 void 345 g_event_init() 346 { 347 348 mtx_init(&g_eventlock, "GEOM orphanage", NULL, MTX_DEF); 349 } 350