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- /*-
- * SPDX-License-Identifier: BSD-3-Clause
- *
- * 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 <sys/param.h>
- #include <sys/malloc.h>
- #include <sys/systm.h>
- #include <sys/kernel.h>
- #include <sys/lock.h>
- #include <sys/mutex.h>
- #include <sys/proc.h>
- #include <sys/errno.h>
- #include <sys/time.h>
- #include <geom/geom.h>
- #include <geom/geom_int.h>
- #include <machine/stdarg.h>
- 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 int g_wither_work;
- #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
- #define EV_INPROGRESS 0x10000
- void
- g_waitidle(struct thread *td)
- {
- g_topology_assert_not();
- mtx_lock(&g_eventlock);
- TSWAIT("GEOM events");
- while (!TAILQ_EMPTY(&g_events))
- msleep(&g_pending_events, &g_eventlock, PPAUSE,
- "g_waitidle", 0);
- TSUNWAIT("GEOM events");
- mtx_unlock(&g_eventlock);
- td->td_pflags &= ~TDP_GEOM;
- }
- static void
- ast_geom(struct thread *td, int tda __unused)
- {
- /*
- * If this thread tickled GEOM, we need to wait for the giggling to
- * stop before we return to userland.
- */
- g_waitidle(td);
- }
- static void
- geom_event_init(void *arg __unused)
- {
- ast_register(TDA_GEOM, ASTR_ASTF_REQUIRED | ASTR_TDP | ASTR_KCLEAR,
- TDP_GEOM, ast_geom);
- }
- SYSINIT(geom_event, SI_SUB_INTRINSIC, SI_ORDER_ANY, geom_event_init, NULL);
- struct g_attrchanged_args {
- struct g_provider *pp;
- const char *attr;
- };
- static void
- g_attr_changed_event(void *arg, int flag)
- {
- struct g_attrchanged_args *args;
- struct g_provider *pp;
- struct g_consumer *cp;
- struct g_consumer *next_cp;
- args = arg;
- pp = args->pp;
- g_topology_assert();
- if (flag != EV_CANCEL && g_shutdown == 0) {
- /*
- * Tell all consumers of the change.
- */
- LIST_FOREACH_SAFE(cp, &pp->consumers, consumers, next_cp) {
- if (cp->geom->attrchanged != NULL)
- cp->geom->attrchanged(cp, args->attr);
- }
- }
- g_free(args);
- }
- int
- g_attr_changed(struct g_provider *pp, const char *attr, int flag)
- {
- struct g_attrchanged_args *args;
- int error;
- args = g_malloc(sizeof *args, flag);
- if (args == NULL)
- return (ENOMEM);
- args->pp = pp;
- args->attr = attr;
- error = g_post_event(g_attr_changed_event, args, flag, pp, NULL);
- if (error != 0)
- g_free(args);
- return (error);
- }
- void
- g_orphan_provider(struct g_provider *pp, int error)
- {
- /* G_VALID_PROVIDER(pp) We likely lack topology lock */
- 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_topology_assert();
- G_VALID_PROVIDER(pp);
- g_trace(G_T_TOPOLOGY, "g_orphan_register(%s)", pp->name);
- g_cancel_event(pp);
- 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.
- */
- LIST_FOREACH_SAFE(cp, &pp->consumers, consumers, cp2) {
- KASSERT(cp->geom->orphan != NULL,
- ("geom %s has no orphan, class %s",
- cp->geom->name, cp->geom->class->name));
- /*
- * XXX: g_dev_orphan method does deferred destroying
- * and it is possible, that other event could already
- * call the orphan method. Check consumer's flags to
- * do not schedule it twice.
- */
- if (cp->flags & G_CF_ORPHAN)
- continue;
- cp->flags |= G_CF_ORPHAN;
- cp->geom->orphan(cp);
- }
- 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;
- g_topology_assert();
- mtx_lock(&g_eventlock);
- pp = TAILQ_FIRST(&g_doorstep);
- if (pp != NULL) {
- G_VALID_PROVIDER(pp);
- TAILQ_REMOVE(&g_doorstep, pp, orphan);
- mtx_unlock(&g_eventlock);
- g_orphan_register(pp);
- return (1);
- }
- ep = TAILQ_FIRST(&g_events);
- if (ep == NULL) {
- wakeup(&g_pending_events);
- return (0);
- }
- ep->flag |= EV_INPROGRESS;
- mtx_unlock(&g_eventlock);
- g_topology_assert();
- ep->func(ep->arg, 0);
- g_topology_assert();
- mtx_lock(&g_eventlock);
- TSRELEASE("GEOM events");
- TAILQ_REMOVE(&g_events, ep, events);
- ep->flag &= ~EV_INPROGRESS;
- if (ep->flag & EV_WAKEUP) {
- ep->flag |= EV_DONE;
- wakeup(ep);
- mtx_unlock(&g_eventlock);
- } else {
- mtx_unlock(&g_eventlock);
- g_free(ep);
- }
- return (1);
- }
- void
- g_run_events(void)
- {
- for (;;) {
- g_topology_lock();
- while (one_event())
- ;
- mtx_assert(&g_eventlock, MA_OWNED);
- if (g_wither_work) {
- g_wither_work = 0;
- mtx_unlock(&g_eventlock);
- g_wither_washer();
- g_topology_unlock();
- } else {
- g_topology_unlock();
- msleep(&g_wait_event, &g_eventlock, PRIBIO | PDROP,
- "-", 0);
- }
- }
- /* NOTREACHED */
- }
- 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;
- }
- TAILQ_FOREACH_SAFE(ep, &g_events, events, epn) {
- if (ep->flag & EV_INPROGRESS)
- continue;
- for (n = 0; n < G_N_EVENTREFS; n++) {
- if (ep->ref[n] == NULL)
- break;
- if (ep->ref[n] != ref)
- continue;
- TSRELEASE("GEOM events");
- TAILQ_REMOVE(&g_events, ep, events);
- ep->func(ep->arg, EV_CANCEL);
- mtx_assert(&g_eventlock, MA_OWNED);
- if (ep->flag & EV_WAKEUP) {
- ep->flag |= (EV_DONE|EV_CANCELED);
- wakeup(ep);
- } else {
- g_free(ep);
- }
- break;
- }
- }
- if (TAILQ_EMPTY(&g_events))
- wakeup(&g_pending_events);
- mtx_unlock(&g_eventlock);
- }
- struct g_event *
- g_alloc_event(int flag)
- {
- KASSERT(flag == M_WAITOK || flag == M_NOWAIT,
- ("Wrong flag to g_alloc_event"));
- return (g_malloc(sizeof(struct g_event), flag | M_ZERO));
- }
- static void
- g_post_event_ep_va(g_event_t *func, void *arg, int wuflag,
- struct g_event *ep, va_list ap)
- {
- void *p;
- u_int n;
- 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);
- TSHOLD("GEOM events");
- TAILQ_INSERT_TAIL(&g_events, ep, events);
- mtx_unlock(&g_eventlock);
- wakeup(&g_wait_event);
- curthread->td_pflags |= TDP_GEOM;
- ast_sched(curthread, TDA_GEOM);
- }
- void
- g_post_event_ep(g_event_t *func, void *arg, struct g_event *ep, ...)
- {
- va_list ap;
- va_start(ap, ep);
- g_post_event_ep_va(func, arg, 0, ep, ap);
- va_end(ap);
- }
- 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;
- g_trace(G_T_TOPOLOGY, "g_post_event_x(%p, %p, %d, %d)",
- func, arg, flag, wuflag);
- KASSERT(wuflag == 0 || wuflag == EV_WAKEUP,
- ("Wrong wuflag in g_post_event_x(0x%x)", wuflag));
- ep = g_alloc_event(flag);
- if (ep == NULL)
- return (ENOMEM);
- if (epp != NULL)
- *epp = ep;
- g_post_event_ep_va(func, arg, wuflag, ep, ap);
- 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);
- }
- void
- g_do_wither(void)
- {
- mtx_lock(&g_eventlock);
- g_wither_work = 1;
- mtx_unlock(&g_eventlock);
- wakeup(&g_wait_event);
- }
- /*
- * 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);
- mtx_lock(&g_eventlock);
- while (!(ep->flag & EV_DONE))
- msleep(ep, &g_eventlock, PRIBIO, "g_waitfor_event", 0);
- if (ep->flag & EV_CANCELED)
- error = EAGAIN;
- mtx_unlock(&g_eventlock);
- g_free(ep);
- return (error);
- }
- void
- g_event_init(void)
- {
- mtx_init(&g_eventlock, "GEOM orphanage", NULL, MTX_DEF);
- }
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