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_waitidlelock(void) 94 { 95 96 g_topology_assert(); 97 while (g_pending_events) { 98 g_topology_unlock(); 99 tsleep(&g_pending_events, PPAUSE, "g_waitidle", hz/5); 100 g_topology_lock(); 101 } 102 } 103 104 void 105 g_orphan_provider(struct g_provider *pp, int error) 106 { 107 108 /* G_VALID_PROVIDER(pp) We likely lack topology lock */ 109 g_trace(G_T_TOPOLOGY, "g_orphan_provider(%p(%s), %d)", 110 pp, pp->name, error); 111 KASSERT(error != 0, 112 ("g_orphan_provider(%p(%s), 0) error must be non-zero\n", 113 pp, pp->name)); 114 115 pp->error = error; 116 mtx_lock(&g_eventlock); 117 KASSERT(!(pp->flags & G_PF_ORPHAN), 118 ("g_orphan_provider(%p(%s)), already an orphan", pp, pp->name)); 119 pp->flags |= G_PF_ORPHAN; 120 TAILQ_INSERT_TAIL(&g_doorstep, pp, orphan); 121 mtx_unlock(&g_eventlock); 122 wakeup(&g_wait_event); 123 } 124 125 /* 126 * This function is called once on each provider which the event handler 127 * finds on its g_doorstep. 128 */ 129 130 static void 131 g_orphan_register(struct g_provider *pp) 132 { 133 struct g_consumer *cp, *cp2; 134 int wf; 135 136 g_topology_assert(); 137 G_VALID_PROVIDER(pp); 138 g_trace(G_T_TOPOLOGY, "g_orphan_register(%s)", pp->name); 139 140 wf = pp->flags & G_PF_WITHER; 141 pp->flags &= ~G_PF_WITHER; 142 143 /* 144 * Tell all consumers the bad news. 145 * Don't be surprised if they self-destruct. 146 */ 147 cp = LIST_FIRST(&pp->consumers); 148 while (cp != NULL) { 149 cp2 = LIST_NEXT(cp, consumers); 150 KASSERT(cp->geom->orphan != NULL, 151 ("geom %s has no orphan, class %s", 152 cp->geom->name, cp->geom->class->name)); 153 cp->geom->orphan(cp); 154 cp = cp2; 155 } 156 if (LIST_EMPTY(&pp->consumers) && wf) 157 g_destroy_provider(pp); 158 else 159 pp->flags |= wf; 160 #ifdef notyet 161 cp = LIST_FIRST(&pp->consumers); 162 if (cp != NULL) 163 return; 164 if (pp->geom->flags & G_GEOM_WITHER) 165 g_destroy_provider(pp); 166 #endif 167 } 168 169 static int 170 one_event(void) 171 { 172 struct g_event *ep; 173 struct g_provider *pp; 174 175 g_topology_lock(); 176 for (;;) { 177 mtx_lock(&g_eventlock); 178 pp = TAILQ_FIRST(&g_doorstep); 179 if (pp != NULL) { 180 G_VALID_PROVIDER(pp); 181 TAILQ_REMOVE(&g_doorstep, pp, orphan); 182 } 183 mtx_unlock(&g_eventlock); 184 if (pp == NULL) 185 break; 186 g_orphan_register(pp); 187 } 188 mtx_lock(&g_eventlock); 189 ep = TAILQ_FIRST(&g_events); 190 if (ep == NULL) { 191 mtx_unlock(&g_eventlock); 192 g_topology_unlock(); 193 return (0); 194 } 195 TAILQ_REMOVE(&g_events, ep, events); 196 mtx_unlock(&g_eventlock); 197 g_topology_assert(); 198 ep->func(ep->arg, 0); 199 g_topology_assert(); 200 if (ep->flag & EV_WAKEUP) { 201 ep->flag |= EV_DONE; 202 wakeup(ep); 203 } else { 204 g_free(ep); 205 } 206 g_pending_events--; 207 if (g_pending_events == 0) 208 wakeup(&g_pending_events); 209 g_topology_unlock(); 210 return (1); 211 } 212 213 void 214 g_run_events() 215 { 216 int i; 217 218 while (one_event()) 219 ; 220 g_topology_lock(); 221 i = g_wither_work; 222 while (i) { 223 i = g_wither_washer(); 224 g_wither_work = i & 1; 225 i &= 2; 226 } 227 g_topology_unlock(); 228 } 229 230 void 231 g_cancel_event(void *ref) 232 { 233 struct g_event *ep, *epn; 234 struct g_provider *pp; 235 u_int n; 236 237 mtx_lock(&g_eventlock); 238 TAILQ_FOREACH(pp, &g_doorstep, orphan) { 239 if (pp != ref) 240 continue; 241 TAILQ_REMOVE(&g_doorstep, pp, orphan); 242 break; 243 } 244 for (ep = TAILQ_FIRST(&g_events); ep != NULL; ep = epn) { 245 epn = TAILQ_NEXT(ep, events); 246 for (n = 0; n < G_N_EVENTREFS; n++) { 247 if (ep->ref[n] == NULL) 248 break; 249 if (ep->ref[n] == ref) { 250 TAILQ_REMOVE(&g_events, ep, events); 251 ep->func(ep->arg, EV_CANCEL); 252 if (ep->flag & EV_WAKEUP) { 253 ep->flag |= EV_DONE; 254 ep->flag |= EV_CANCELED; 255 wakeup(ep); 256 } else { 257 g_free(ep); 258 } 259 if (--g_pending_events == 0) 260 wakeup(&g_pending_events); 261 break; 262 } 263 } 264 } 265 mtx_unlock(&g_eventlock); 266 } 267 268 static int 269 g_post_event_x(g_event_t *func, void *arg, int flag, int wuflag, struct g_event **epp, va_list ap) 270 { 271 struct g_event *ep; 272 void *p; 273 u_int n; 274 275 g_trace(G_T_TOPOLOGY, "g_post_event_x(%p, %p, %d, %d)", 276 func, arg, flag, wakeup); 277 KASSERT(wuflag == 0 || wuflag == EV_WAKEUP, 278 ("Wrong wuflag in g_post_event_x(0x%x)", wuflag)); 279 ep = g_malloc(sizeof *ep, flag | M_ZERO); 280 if (ep == NULL) 281 return (ENOMEM); 282 ep->flag = wuflag; 283 for (n = 0; n < G_N_EVENTREFS; n++) { 284 p = va_arg(ap, void *); 285 if (p == NULL) 286 break; 287 g_trace(G_T_TOPOLOGY, " ref %p", p); 288 ep->ref[n] = p; 289 } 290 KASSERT(p == NULL, ("Too many references to event")); 291 ep->func = func; 292 ep->arg = arg; 293 mtx_lock(&g_eventlock); 294 g_pending_events++; 295 TAILQ_INSERT_TAIL(&g_events, ep, events); 296 mtx_unlock(&g_eventlock); 297 wakeup(&g_wait_event); 298 if (epp != NULL) 299 *epp = ep; 300 curthread->td_pflags |= TDP_GEOM; 301 return (0); 302 } 303 304 int 305 g_post_event(g_event_t *func, void *arg, int flag, ...) 306 { 307 va_list ap; 308 int i; 309 310 KASSERT(flag == M_WAITOK || flag == M_NOWAIT, 311 ("Wrong flag to g_post_event")); 312 va_start(ap, flag); 313 i = g_post_event_x(func, arg, flag, 0, NULL, ap); 314 va_end(ap); 315 return (i); 316 } 317 318 void 319 g_do_wither() { 320 321 g_wither_work = 1; 322 wakeup(&g_wait_event); 323 } 324 325 /* 326 * XXX: It might actually be useful to call this function with topology held. 327 * XXX: This would ensure that the event gets created before anything else 328 * XXX: changes. At present all users have a handle on things in some other 329 * XXX: way, so this remains an XXX for now. 330 */ 331 332 int 333 g_waitfor_event(g_event_t *func, void *arg, int flag, ...) 334 { 335 va_list ap; 336 struct g_event *ep; 337 int error; 338 339 g_topology_assert_not(); 340 KASSERT(flag == M_WAITOK || flag == M_NOWAIT, 341 ("Wrong flag to g_post_event")); 342 va_start(ap, flag); 343 error = g_post_event_x(func, arg, flag, EV_WAKEUP, &ep, ap); 344 va_end(ap); 345 if (error) 346 return (error); 347 do 348 tsleep(ep, PRIBIO, "g_waitfor_event", hz); 349 while (!(ep->flag & EV_DONE)); 350 if (ep->flag & EV_CANCELED) 351 error = EAGAIN; 352 g_free(ep); 353 return (error); 354 } 355 356 void 357 g_event_init() 358 { 359 360 mtx_init(&g_eventlock, "GEOM orphanage", NULL, MTX_DEF); 361 } 362