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 wf = pp->flags & G_PF_WITHER; 149 pp->flags &= ~G_PF_WITHER; 150 151 /* 152 * Tell all consumers the bad news. 153 * Don't be surprised if they self-destruct. 154 */ 155 cp = LIST_FIRST(&pp->consumers); 156 while (cp != NULL) { 157 cp2 = LIST_NEXT(cp, consumers); 158 KASSERT(cp->geom->orphan != NULL, 159 ("geom %s has no orphan, class %s", 160 cp->geom->name, cp->geom->class->name)); 161 cp->geom->orphan(cp); 162 cp = cp2; 163 } 164 if (LIST_EMPTY(&pp->consumers) && wf) 165 g_destroy_provider(pp); 166 else 167 pp->flags |= wf; 168 #ifdef notyet 169 cp = LIST_FIRST(&pp->consumers); 170 if (cp != NULL) 171 return; 172 if (pp->geom->flags & G_GEOM_WITHER) 173 g_destroy_provider(pp); 174 #endif 175 } 176 177 static int 178 one_event(void) 179 { 180 struct g_event *ep; 181 struct g_provider *pp; 182 183 g_topology_lock(); 184 for (;;) { 185 mtx_lock(&g_eventlock); 186 pp = TAILQ_FIRST(&g_doorstep); 187 if (pp != NULL) { 188 G_VALID_PROVIDER(pp); 189 TAILQ_REMOVE(&g_doorstep, pp, orphan); 190 } 191 mtx_unlock(&g_eventlock); 192 if (pp == NULL) 193 break; 194 g_orphan_register(pp); 195 } 196 mtx_lock(&g_eventlock); 197 ep = TAILQ_FIRST(&g_events); 198 if (ep == NULL) { 199 wakeup(&g_pending_events); 200 mtx_unlock(&g_eventlock); 201 g_topology_unlock(); 202 return (0); 203 } 204 mtx_unlock(&g_eventlock); 205 g_topology_assert(); 206 ep->func(ep->arg, 0); 207 g_topology_assert(); 208 mtx_lock(&g_eventlock); 209 TAILQ_REMOVE(&g_events, ep, events); 210 mtx_unlock(&g_eventlock); 211 if (ep->flag & EV_WAKEUP) { 212 ep->flag |= EV_DONE; 213 wakeup(ep); 214 } else { 215 g_free(ep); 216 } 217 g_topology_unlock(); 218 return (1); 219 } 220 221 void 222 g_run_events() 223 { 224 int i; 225 226 while (one_event()) 227 ; 228 g_topology_lock(); 229 i = g_wither_work; 230 while (i) { 231 i = g_wither_washer(); 232 g_wither_work = i & 1; 233 i &= 2; 234 } 235 g_topology_unlock(); 236 } 237 238 void 239 g_cancel_event(void *ref) 240 { 241 struct g_event *ep, *epn; 242 struct g_provider *pp; 243 u_int n; 244 245 mtx_lock(&g_eventlock); 246 TAILQ_FOREACH(pp, &g_doorstep, orphan) { 247 if (pp != ref) 248 continue; 249 TAILQ_REMOVE(&g_doorstep, pp, orphan); 250 break; 251 } 252 TAILQ_FOREACH_SAFE(ep, &g_events, events, epn) { 253 for (n = 0; n < G_N_EVENTREFS; n++) { 254 if (ep->ref[n] == NULL) 255 break; 256 if (ep->ref[n] != ref) 257 continue; 258 TAILQ_REMOVE(&g_events, ep, events); 259 ep->func(ep->arg, EV_CANCEL); 260 mtx_assert(&g_eventlock, MA_OWNED); 261 if (ep->flag & EV_WAKEUP) { 262 ep->flag |= (EV_DONE|EV_CANCELED); 263 wakeup(ep); 264 } else { 265 g_free(ep); 266 } 267 break; 268 } 269 } 270 if (TAILQ_EMPTY(&g_events)) 271 wakeup(&g_pending_events); 272 mtx_unlock(&g_eventlock); 273 } 274 275 static int 276 g_post_event_x(g_event_t *func, void *arg, int flag, int wuflag, struct g_event **epp, va_list ap) 277 { 278 struct g_event *ep; 279 void *p; 280 u_int n; 281 282 g_trace(G_T_TOPOLOGY, "g_post_event_x(%p, %p, %d, %d)", 283 func, arg, flag, wuflag); 284 KASSERT(wuflag == 0 || wuflag == EV_WAKEUP, 285 ("Wrong wuflag in g_post_event_x(0x%x)", wuflag)); 286 ep = g_malloc(sizeof *ep, flag | M_ZERO); 287 if (ep == NULL) 288 return (ENOMEM); 289 ep->flag = wuflag; 290 for (n = 0; n < G_N_EVENTREFS; n++) { 291 p = va_arg(ap, void *); 292 if (p == NULL) 293 break; 294 g_trace(G_T_TOPOLOGY, " ref %p", p); 295 ep->ref[n] = p; 296 } 297 KASSERT(p == NULL, ("Too many references to event")); 298 ep->func = func; 299 ep->arg = arg; 300 mtx_lock(&g_eventlock); 301 TAILQ_INSERT_TAIL(&g_events, ep, events); 302 mtx_unlock(&g_eventlock); 303 wakeup(&g_wait_event); 304 if (epp != NULL) 305 *epp = ep; 306 curthread->td_pflags |= TDP_GEOM; 307 return (0); 308 } 309 310 int 311 g_post_event(g_event_t *func, void *arg, int flag, ...) 312 { 313 va_list ap; 314 int i; 315 316 KASSERT(flag == M_WAITOK || flag == M_NOWAIT, 317 ("Wrong flag to g_post_event")); 318 va_start(ap, flag); 319 i = g_post_event_x(func, arg, flag, 0, NULL, ap); 320 va_end(ap); 321 return (i); 322 } 323 324 void 325 g_do_wither() { 326 327 g_wither_work = 1; 328 wakeup(&g_wait_event); 329 } 330 331 /* 332 * XXX: It might actually be useful to call this function with topology held. 333 * XXX: This would ensure that the event gets created before anything else 334 * XXX: changes. At present all users have a handle on things in some other 335 * XXX: way, so this remains an XXX for now. 336 */ 337 338 int 339 g_waitfor_event(g_event_t *func, void *arg, int flag, ...) 340 { 341 va_list ap; 342 struct g_event *ep; 343 int error; 344 345 g_topology_assert_not(); 346 KASSERT(flag == M_WAITOK || flag == M_NOWAIT, 347 ("Wrong flag to g_post_event")); 348 va_start(ap, flag); 349 error = g_post_event_x(func, arg, flag, EV_WAKEUP, &ep, ap); 350 va_end(ap); 351 if (error) 352 return (error); 353 do 354 tsleep(ep, PRIBIO, "g_waitfor_event", hz); 355 while (!(ep->flag & EV_DONE)); 356 if (ep->flag & EV_CANCELED) 357 error = EAGAIN; 358 g_free(ep); 359 return (error); 360 } 361 362 void 363 g_event_init() 364 { 365 366 mtx_init(&g_eventlock, "GEOM orphanage", NULL, MTX_DEF); 367 } 368