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