The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]

FreeBSD/Linux Kernel Cross Reference
sys/geom/geom_event.c

Version: -  FREEBSD  -  FREEBSD-13-STABLE  -  FREEBSD-13-0  -  FREEBSD-12-STABLE  -  FREEBSD-12-0  -  FREEBSD-11-STABLE  -  FREEBSD-11-0  -  FREEBSD-10-STABLE  -  FREEBSD-10-0  -  FREEBSD-9-STABLE  -  FREEBSD-9-0  -  FREEBSD-8-STABLE  -  FREEBSD-8-0  -  FREEBSD-7-STABLE  -  FREEBSD-7-0  -  FREEBSD-6-STABLE  -  FREEBSD-6-0  -  FREEBSD-5-STABLE  -  FREEBSD-5-0  -  FREEBSD-4-STABLE  -  FREEBSD-3-STABLE  -  FREEBSD22  -  l41  -  OPENBSD  -  linux-2.6  -  MK84  -  PLAN9  -  xnu-8792 
SearchContext: -  none  -  3  -  10 

    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: releng/5.3/sys/geom/geom_event.c 136588 2004-10-16 08:43:07Z cvs2svn $");
   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 <machine/stdarg.h>
   51 #include <sys/errno.h>
   52 #include <sys/time.h>
   53 #include <geom/geom.h>
   54 #include <geom/geom_int.h>
   55 
   56 TAILQ_HEAD(event_tailq_head, g_event);
   57 
   58 static struct event_tailq_head g_events = TAILQ_HEAD_INITIALIZER(g_events);
   59 static u_int g_pending_events;
   60 static TAILQ_HEAD(,g_provider) g_doorstep = TAILQ_HEAD_INITIALIZER(g_doorstep);
   61 static struct mtx g_eventlock;
   62 static int g_wither_work;
   63 
   64 #define G_N_EVENTREFS           20
   65 
   66 struct g_event {
   67         TAILQ_ENTRY(g_event)    events;
   68         g_event_t               *func;
   69         void                    *arg;
   70         int                     flag;
   71         void                    *ref[G_N_EVENTREFS];
   72 };
   73 
   74 #define EV_DONE         0x80000
   75 #define EV_WAKEUP       0x40000
   76 #define EV_CANCELED     0x20000
   77 
   78 void
   79 g_waitidle(void)
   80 {
   81 
   82         while (g_pending_events)
   83                 tsleep(&g_pending_events, PPAUSE, "g_waitidle", hz/5);
   84 }
   85 
   86 void
   87 g_orphan_provider(struct g_provider *pp, int error)
   88 {
   89 
   90         /* G_VALID_PROVIDER(pp)  We likely lack topology lock */
   91         g_trace(G_T_TOPOLOGY, "g_orphan_provider(%p(%s), %d)",
   92             pp, pp->name, error);
   93         KASSERT(error != 0,
   94             ("g_orphan_provider(%p(%s), 0) error must be non-zero\n",
   95              pp, pp->name));
   96         
   97         pp->error = error;
   98         mtx_lock(&g_eventlock);
   99         KASSERT(!(pp->flags & G_PF_ORPHAN),
  100             ("g_orphan_provider(%p(%s)), already an orphan", pp, pp->name));
  101         pp->flags |= G_PF_ORPHAN;
  102         TAILQ_INSERT_TAIL(&g_doorstep, pp, orphan);
  103         mtx_unlock(&g_eventlock);
  104         wakeup(&g_wait_event);
  105 }
  106 
  107 /*
  108  * This function is called once on each provider which the event handler
  109  * finds on its g_doorstep.
  110  */
  111 
  112 static void
  113 g_orphan_register(struct g_provider *pp)
  114 {
  115         struct g_consumer *cp, *cp2;
  116         int wf;
  117 
  118         g_topology_assert();
  119         G_VALID_PROVIDER(pp);
  120         g_trace(G_T_TOPOLOGY, "g_orphan_register(%s)", pp->name);
  121 
  122         wf = pp->flags & G_PF_WITHER;
  123         pp->flags &= ~G_PF_WITHER;
  124 
  125         /*
  126          * Tell all consumers the bad news.
  127          * Don't be surprised if they self-destruct.
  128          */
  129         cp = LIST_FIRST(&pp->consumers);
  130         while (cp != NULL) {
  131                 cp2 = LIST_NEXT(cp, consumers);
  132                 KASSERT(cp->geom->orphan != NULL,
  133                     ("geom %s has no orphan, class %s",
  134                     cp->geom->name, cp->geom->class->name));
  135                 cp->geom->orphan(cp);
  136                 cp = cp2;
  137         }
  138         if (LIST_EMPTY(&pp->consumers) && wf)
  139                 g_destroy_provider(pp);
  140         else
  141                 pp->flags |= wf;
  142 #ifdef notyet
  143         cp = LIST_FIRST(&pp->consumers);
  144         if (cp != NULL)
  145                 return;
  146         if (pp->geom->flags & G_GEOM_WITHER)
  147                 g_destroy_provider(pp);
  148 #endif
  149 }
  150 
  151 static int
  152 one_event(void)
  153 {
  154         struct g_event *ep;
  155         struct g_provider *pp;
  156 
  157         g_topology_lock();
  158         for (;;) {
  159                 mtx_lock(&g_eventlock);
  160                 pp = TAILQ_FIRST(&g_doorstep);
  161                 if (pp != NULL) {
  162                         G_VALID_PROVIDER(pp);
  163                         TAILQ_REMOVE(&g_doorstep, pp, orphan);
  164                 }
  165                 mtx_unlock(&g_eventlock);
  166                 if (pp == NULL)
  167                         break;
  168                 g_orphan_register(pp);
  169         }
  170         mtx_lock(&g_eventlock);
  171         ep = TAILQ_FIRST(&g_events);
  172         if (ep == NULL) {
  173                 mtx_unlock(&g_eventlock);
  174                 g_topology_unlock();
  175                 return (0);
  176         }
  177         TAILQ_REMOVE(&g_events, ep, events);
  178         mtx_unlock(&g_eventlock);
  179         g_topology_assert();
  180         ep->func(ep->arg, 0);
  181         g_topology_assert();
  182         if (ep->flag & EV_WAKEUP) {
  183                 ep->flag |= EV_DONE;
  184                 wakeup(ep);
  185         } else {
  186                 g_free(ep);
  187         }
  188         g_pending_events--;
  189         if (g_pending_events == 0)
  190                 wakeup(&g_pending_events);
  191         g_topology_unlock();
  192         return (1);
  193 }
  194 
  195 void
  196 g_run_events()
  197 {
  198         int i;
  199 
  200         while (one_event())
  201                 ;
  202         g_topology_lock();
  203         i = g_wither_work;
  204         while (i) {
  205                 i = g_wither_washer();
  206                 g_wither_work = i & 1;
  207                 i &= 2;
  208         }
  209         g_topology_unlock();
  210 }
  211 
  212 void
  213 g_cancel_event(void *ref)
  214 {
  215         struct g_event *ep, *epn;
  216         struct g_provider *pp;
  217         u_int n;
  218 
  219         mtx_lock(&g_eventlock);
  220         TAILQ_FOREACH(pp, &g_doorstep, orphan) {
  221                 if (pp != ref)
  222                         continue;
  223                 TAILQ_REMOVE(&g_doorstep, pp, orphan);
  224                 break;
  225         }
  226         for (ep = TAILQ_FIRST(&g_events); ep != NULL; ep = epn) {
  227                 epn = TAILQ_NEXT(ep, events);
  228                 for (n = 0; n < G_N_EVENTREFS; n++) {
  229                         if (ep->ref[n] == NULL)
  230                                 break;
  231                         if (ep->ref[n] == ref) {
  232                                 TAILQ_REMOVE(&g_events, ep, events);
  233                                 ep->func(ep->arg, EV_CANCEL);
  234                                 if (ep->flag & EV_WAKEUP) {
  235                                         ep->flag |= EV_DONE;
  236                                         ep->flag |= EV_CANCELED;
  237                                         wakeup(ep);
  238                                 } else {
  239                                         g_free(ep);
  240                                 }
  241                                 if (--g_pending_events == 0)
  242                                         wakeup(&g_pending_events);
  243                                 break;
  244                         }
  245                 }
  246         }
  247         mtx_unlock(&g_eventlock);
  248 }
  249 
  250 static int
  251 g_post_event_x(g_event_t *func, void *arg, int flag, int wuflag, struct g_event **epp, va_list ap)
  252 {
  253         struct g_event *ep;
  254         void *p;
  255         u_int n;
  256 
  257         g_trace(G_T_TOPOLOGY, "g_post_event_x(%p, %p, %d, %d)",
  258             func, arg, flag, wakeup);
  259         KASSERT(wuflag == 0 || wuflag == EV_WAKEUP,
  260             ("Wrong wuflag in g_post_event_x(0x%x)", wuflag));
  261         ep = g_malloc(sizeof *ep, flag | M_ZERO);
  262         if (ep == NULL)
  263                 return (ENOMEM);
  264         ep->flag = wuflag;
  265         for (n = 0; n < G_N_EVENTREFS; n++) {
  266                 p = va_arg(ap, void *);
  267                 if (p == NULL)
  268                         break;
  269                 g_trace(G_T_TOPOLOGY, "  ref %p", p);
  270                 ep->ref[n] = p;
  271         }
  272         KASSERT(p == NULL, ("Too many references to event"));
  273         ep->func = func;
  274         ep->arg = arg;
  275         mtx_lock(&g_eventlock);
  276         g_pending_events++;
  277         TAILQ_INSERT_TAIL(&g_events, ep, events);
  278         mtx_unlock(&g_eventlock);
  279         wakeup(&g_wait_event);
  280         if (epp != NULL)
  281                 *epp = ep;
  282         return (0);
  283 }
  284 
  285 int
  286 g_post_event(g_event_t *func, void *arg, int flag, ...)
  287 {
  288         va_list ap;
  289         int i;
  290 
  291         KASSERT(flag == M_WAITOK || flag == M_NOWAIT,
  292             ("Wrong flag to g_post_event"));
  293         va_start(ap, flag);
  294         i = g_post_event_x(func, arg, flag, 0, NULL, ap);
  295         va_end(ap);
  296         return (i);
  297 }
  298 
  299 void
  300 g_do_wither() {
  301 
  302         g_wither_work = 1;
  303         wakeup(&g_wait_event);
  304 }
  305 
  306 /*
  307  * XXX: It might actually be useful to call this function with topology held.
  308  * XXX: This would ensure that the event gets created before anything else
  309  * XXX: changes.  At present all users have a handle on things in some other
  310  * XXX: way, so this remains an XXX for now.
  311  */
  312 
  313 int
  314 g_waitfor_event(g_event_t *func, void *arg, int flag, ...)
  315 {
  316         va_list ap;
  317         struct g_event *ep;
  318         int error;
  319 
  320         g_topology_assert_not();
  321         KASSERT(flag == M_WAITOK || flag == M_NOWAIT,
  322             ("Wrong flag to g_post_event"));
  323         va_start(ap, flag);
  324         error = g_post_event_x(func, arg, flag, EV_WAKEUP, &ep, ap);
  325         va_end(ap);
  326         if (error)
  327                 return (error);
  328         do 
  329                 tsleep(ep, PRIBIO, "g_waitfor_event", hz);
  330         while (!(ep->flag & EV_DONE));
  331         if (ep->flag & EV_CANCELED)
  332                 error = EAGAIN;
  333         g_free(ep);
  334         return (error);
  335 }
  336 
  337 void
  338 g_event_init()
  339 {
  340 
  341         mtx_init(&g_eventlock, "GEOM orphanage", NULL, MTX_DEF);
  342 }

Cache object: a5ef72972e651411a4886a24ffb82a6f


[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]


This page is part of the FreeBSD/Linux Linux Kernel Cross-Reference, and was automatically generated using a modified version of the LXR engine.