/*- * Copyright (c) 2002 Poul-Henning Kamp * Copyright (c) 2002 Networks Associates Technology, Inc. * All rights reserved. * * This software was developed for the FreeBSD Project by Poul-Henning Kamp * and NAI Labs, the Security Research Division of Network Associates, Inc. * under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the * DARPA CHATS research program. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. The names of the authors may not be used to endorse or promote * products derived from this software without specific prior written * permission. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ /* * XXX: How do we in general know that objects referenced in events * have not been destroyed before we get around to handle the event ? */ #include __FBSDID("$FreeBSD$"); #include #include #include #include #include #include #include #include #include #include #include TAILQ_HEAD(event_tailq_head, g_event); static struct event_tailq_head g_events = TAILQ_HEAD_INITIALIZER(g_events); static u_int g_pending_events; static TAILQ_HEAD(,g_provider) g_doorstep = TAILQ_HEAD_INITIALIZER(g_doorstep); static struct mtx g_eventlock; static struct sx g_eventstall; #define G_N_EVENTREFS 20 struct g_event { TAILQ_ENTRY(g_event) events; g_event_t *func; void *arg; int flag; void *ref[G_N_EVENTREFS]; }; #define EV_DONE 0x80000 #define EV_WAKEUP 0x40000 #define EV_CANCELED 0x20000 void g_waitidle(void) { while (g_pending_events) tsleep(&g_pending_events, PPAUSE, "g_waitidle", hz/5); } void g_stall_events(void) { sx_xlock(&g_eventstall); } void g_release_events(void) { sx_xunlock(&g_eventstall); } void g_orphan_provider(struct g_provider *pp, int error) { g_trace(G_T_TOPOLOGY, "g_orphan_provider(%p(%s), %d)", pp, pp->name, error); KASSERT(error != 0, ("g_orphan_provider(%p(%s), 0) error must be non-zero\n", pp, pp->name)); pp->error = error; mtx_lock(&g_eventlock); KASSERT(!(pp->flags & G_PF_ORPHAN), ("g_orphan_provider(%p(%s)), already an orphan", pp, pp->name)); pp->flags |= G_PF_ORPHAN; TAILQ_INSERT_TAIL(&g_doorstep, pp, orphan); mtx_unlock(&g_eventlock); wakeup(&g_wait_event); } /* * This function is called once on each provider which the event handler * finds on its g_doorstep. */ static void g_orphan_register(struct g_provider *pp) { struct g_consumer *cp, *cp2; int wf; g_trace(G_T_TOPOLOGY, "g_orphan_register(%s)", pp->name); g_topology_assert(); wf = pp->flags & G_PF_WITHER; pp->flags &= ~G_PF_WITHER; /* * Tell all consumers the bad news. * Don't be surprised if they self-destruct. */ cp = LIST_FIRST(&pp->consumers); while (cp != NULL) { cp2 = LIST_NEXT(cp, consumers); KASSERT(cp->geom->orphan != NULL, ("geom %s has no orphan, class %s", cp->geom->name, cp->geom->class->name)); cp->geom->orphan(cp); cp = cp2; } if (LIST_EMPTY(&pp->consumers) && wf) g_destroy_provider(pp); else pp->flags |= wf; #ifdef notyet cp = LIST_FIRST(&pp->consumers); if (cp != NULL) return; if (pp->geom->flags & G_GEOM_WITHER) g_destroy_provider(pp); #endif } static int one_event(void) { struct g_event *ep; struct g_provider *pp; sx_xlock(&g_eventstall); g_topology_lock(); for (;;) { mtx_lock(&g_eventlock); pp = TAILQ_FIRST(&g_doorstep); if (pp != NULL) TAILQ_REMOVE(&g_doorstep, pp, orphan); mtx_unlock(&g_eventlock); if (pp == NULL) break; g_orphan_register(pp); } mtx_lock(&g_eventlock); ep = TAILQ_FIRST(&g_events); if (ep == NULL) { mtx_unlock(&g_eventlock); g_topology_unlock(); sx_xunlock(&g_eventstall); return (0); } TAILQ_REMOVE(&g_events, ep, events); mtx_unlock(&g_eventlock); g_topology_assert(); ep->func(ep->arg, 0); g_topology_assert(); if (ep->flag & EV_WAKEUP) { ep->flag |= EV_DONE; wakeup(ep); } else { g_free(ep); } g_pending_events--; if (g_pending_events == 0) wakeup(&g_pending_events); g_topology_unlock(); sx_xunlock(&g_eventstall); return (1); } void g_run_events() { while (one_event()) ; } void g_cancel_event(void *ref) { struct g_event *ep, *epn; struct g_provider *pp; u_int n; mtx_lock(&g_eventlock); TAILQ_FOREACH(pp, &g_doorstep, orphan) { if (pp != ref) continue; TAILQ_REMOVE(&g_doorstep, pp, orphan); break; } for (ep = TAILQ_FIRST(&g_events); ep != NULL; ep = epn) { epn = TAILQ_NEXT(ep, events); for (n = 0; n < G_N_EVENTREFS; n++) { if (ep->ref[n] == NULL) break; if (ep->ref[n] == ref) { TAILQ_REMOVE(&g_events, ep, events); ep->func(ep->arg, EV_CANCEL); if (ep->flag & EV_WAKEUP) { ep->flag |= EV_DONE; ep->flag |= EV_CANCELED; wakeup(ep); } else { g_free(ep); } if (--g_pending_events == 0) wakeup(&g_pending_events); break; } } } mtx_unlock(&g_eventlock); } static int g_post_event_x(g_event_t *func, void *arg, int flag, int wuflag, struct g_event **epp, va_list ap) { struct g_event *ep; void *p; u_int n; g_trace(G_T_TOPOLOGY, "g_post_event_x(%p, %p, %d, %d)", func, arg, flag, wakeup); KASSERT(wuflag == 0 || wuflag == EV_WAKEUP, ("Wrong wuflag in g_post_event_x(0x%x)", wuflag)); ep = g_malloc(sizeof *ep, flag | M_ZERO); if (ep == NULL) return (ENOMEM); ep->flag = wuflag; for (n = 0; n < G_N_EVENTREFS; n++) { p = va_arg(ap, void *); if (p == NULL) break; g_trace(G_T_TOPOLOGY, " ref %p", p); ep->ref[n] = p; } KASSERT(p == NULL, ("Too many references to event")); ep->func = func; ep->arg = arg; mtx_lock(&g_eventlock); g_pending_events++; TAILQ_INSERT_TAIL(&g_events, ep, events); mtx_unlock(&g_eventlock); wakeup(&g_wait_event); if (epp != NULL) *epp = ep; return (0); } int g_post_event(g_event_t *func, void *arg, int flag, ...) { va_list ap; int i; KASSERT(flag == M_WAITOK || flag == M_NOWAIT, ("Wrong flag to g_post_event")); va_start(ap, flag); i = g_post_event_x(func, arg, flag, 0, NULL, ap); va_end(ap); return (i); } /* * XXX: It might actually be useful to call this function with topology held. * XXX: This would ensure that the event gets created before anything else * XXX: changes. At present all users have a handle on things in some other * XXX: way, so this remains an XXX for now. */ int g_waitfor_event(g_event_t *func, void *arg, int flag, ...) { va_list ap; struct g_event *ep; int error; /* g_topology_assert_not(); */ KASSERT(flag == M_WAITOK || flag == M_NOWAIT, ("Wrong flag to g_post_event")); va_start(ap, flag); error = g_post_event_x(func, arg, flag, EV_WAKEUP, &ep, ap); va_end(ap); if (error) return (error); do tsleep(ep, PRIBIO, "g_waitfor_event", hz); while (!(ep->flag & EV_DONE)); if (ep->flag & EV_CANCELED) error = EAGAIN; g_free(ep); return (error); } void g_event_init() { mtx_init(&g_eventlock, "GEOM orphanage", NULL, MTX_DEF); sx_init(&g_eventstall, "GEOM event stalling"); }