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  * SPDX-License-Identifier: BSD-3-Clause
    3  *
    4  * Copyright (c) 2002 Poul-Henning Kamp
    5  * Copyright (c) 2002 Networks Associates Technology, Inc.
    6  * All rights reserved.
    7  *
    8  * This software was developed for the FreeBSD Project by Poul-Henning Kamp
    9  * and NAI Labs, the Security Research Division of Network Associates, Inc.
   10  * under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the
   11  * DARPA CHATS research program.
   12  *
   13  * Redistribution and use in source and binary forms, with or without
   14  * modification, are permitted provided that the following conditions
   15  * are met:
   16  * 1. Redistributions of source code must retain the above copyright
   17  *    notice, this list of conditions and the following disclaimer.
   18  * 2. Redistributions in binary form must reproduce the above copyright
   19  *    notice, this list of conditions and the following disclaimer in the
   20  *    documentation and/or other materials provided with the distribution.
   21  * 3. The names of the authors may not be used to endorse or promote
   22  *    products derived from this software without specific prior written
   23  *    permission.
   24  *
   25  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   26  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   27  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   28  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   29  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   30  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   31  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   32  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   33  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   34  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   35  * SUCH DAMAGE.
   36  */
   37 
   38 /*
   39  * XXX: How do we in general know that objects referenced in events
   40  * have not been destroyed before we get around to handle the event ?
   41  */
   42 
   43 #include <sys/cdefs.h>
   44 __FBSDID("$FreeBSD$");
   45 
   46 #include <sys/param.h>
   47 #include <sys/malloc.h>
   48 #include <sys/systm.h>
   49 #include <sys/kernel.h>
   50 #include <sys/lock.h>
   51 #include <sys/mutex.h>
   52 #include <sys/proc.h>
   53 #include <sys/errno.h>
   54 #include <sys/time.h>
   55 #include <geom/geom.h>
   56 #include <geom/geom_int.h>
   57 
   58 #include <machine/stdarg.h>
   59 
   60 TAILQ_HEAD(event_tailq_head, g_event);
   61 
   62 static struct event_tailq_head g_events = TAILQ_HEAD_INITIALIZER(g_events);
   63 static u_int g_pending_events;
   64 static TAILQ_HEAD(,g_provider) g_doorstep = TAILQ_HEAD_INITIALIZER(g_doorstep);
   65 static struct mtx g_eventlock;
   66 static int g_wither_work;
   67 
   68 #define G_N_EVENTREFS           20
   69 
   70 struct g_event {
   71         TAILQ_ENTRY(g_event)    events;
   72         g_event_t               *func;
   73         void                    *arg;
   74         int                     flag;
   75         void                    *ref[G_N_EVENTREFS];
   76 };
   77 
   78 #define EV_DONE         0x80000
   79 #define EV_WAKEUP       0x40000
   80 #define EV_CANCELED     0x20000
   81 #define EV_INPROGRESS   0x10000
   82 
   83 void
   84 g_waitidle(struct thread *td)
   85 {
   86 
   87         g_topology_assert_not();
   88 
   89         mtx_lock(&g_eventlock);
   90         TSWAIT("GEOM events");
   91         while (!TAILQ_EMPTY(&g_events))
   92                 msleep(&g_pending_events, &g_eventlock, PPAUSE,
   93                     "g_waitidle", 0);
   94         TSUNWAIT("GEOM events");
   95         mtx_unlock(&g_eventlock);
   96         td->td_pflags &= ~TDP_GEOM;
   97 }
   98 
   99 static void
  100 ast_geom(struct thread *td, int tda __unused)
  101 {
  102         /*
  103          * If this thread tickled GEOM, we need to wait for the giggling to
  104          * stop before we return to userland.
  105          */
  106         g_waitidle(td);
  107 }
  108 
  109 static void
  110 geom_event_init(void *arg __unused)
  111 {
  112         ast_register(TDA_GEOM, ASTR_ASTF_REQUIRED | ASTR_TDP | ASTR_KCLEAR,
  113             TDP_GEOM, ast_geom);
  114 }
  115 SYSINIT(geom_event, SI_SUB_INTRINSIC, SI_ORDER_ANY, geom_event_init, NULL);
  116 
  117 struct g_attrchanged_args {
  118         struct g_provider *pp;
  119         const char *attr;
  120 };
  121 
  122 static void
  123 g_attr_changed_event(void *arg, int flag)
  124 {
  125         struct g_attrchanged_args *args;
  126         struct g_provider *pp;
  127         struct g_consumer *cp;
  128         struct g_consumer *next_cp;
  129 
  130         args = arg;
  131         pp = args->pp;
  132 
  133         g_topology_assert();
  134         if (flag != EV_CANCEL && g_shutdown == 0) {
  135                 /*
  136                  * Tell all consumers of the change.
  137                  */
  138                 LIST_FOREACH_SAFE(cp, &pp->consumers, consumers, next_cp) {
  139                         if (cp->geom->attrchanged != NULL)
  140                                 cp->geom->attrchanged(cp, args->attr);
  141                 }
  142         }
  143         g_free(args);
  144 }
  145 
  146 int
  147 g_attr_changed(struct g_provider *pp, const char *attr, int flag)
  148 {
  149         struct g_attrchanged_args *args;
  150         int error;
  151 
  152         args = g_malloc(sizeof *args, flag);
  153         if (args == NULL)
  154                 return (ENOMEM);
  155         args->pp = pp;
  156         args->attr = attr;
  157         error = g_post_event(g_attr_changed_event, args, flag, pp, NULL);
  158         if (error != 0)
  159                 g_free(args);
  160         return (error);
  161 }
  162 
  163 void
  164 g_orphan_provider(struct g_provider *pp, int error)
  165 {
  166 
  167         /* G_VALID_PROVIDER(pp)  We likely lack topology lock */
  168         g_trace(G_T_TOPOLOGY, "g_orphan_provider(%p(%s), %d)",
  169             pp, pp->name, error);
  170         KASSERT(error != 0,
  171             ("g_orphan_provider(%p(%s), 0) error must be non-zero\n",
  172              pp, pp->name));
  173 
  174         pp->error = error;
  175         mtx_lock(&g_eventlock);
  176         KASSERT(!(pp->flags & G_PF_ORPHAN),
  177             ("g_orphan_provider(%p(%s)), already an orphan", pp, pp->name));
  178         pp->flags |= G_PF_ORPHAN;
  179         TAILQ_INSERT_TAIL(&g_doorstep, pp, orphan);
  180         mtx_unlock(&g_eventlock);
  181         wakeup(&g_wait_event);
  182 }
  183 
  184 /*
  185  * This function is called once on each provider which the event handler
  186  * finds on its g_doorstep.
  187  */
  188 
  189 static void
  190 g_orphan_register(struct g_provider *pp)
  191 {
  192         struct g_consumer *cp, *cp2;
  193         int wf;
  194 
  195         g_topology_assert();
  196         G_VALID_PROVIDER(pp);
  197         g_trace(G_T_TOPOLOGY, "g_orphan_register(%s)", pp->name);
  198 
  199         g_cancel_event(pp);
  200 
  201         wf = pp->flags & G_PF_WITHER;
  202         pp->flags &= ~G_PF_WITHER;
  203 
  204         /*
  205          * Tell all consumers the bad news.
  206          * Don't be surprised if they self-destruct.
  207          */
  208         LIST_FOREACH_SAFE(cp, &pp->consumers, consumers, cp2) {
  209                 KASSERT(cp->geom->orphan != NULL,
  210                     ("geom %s has no orphan, class %s",
  211                     cp->geom->name, cp->geom->class->name));
  212                 /*
  213                  * XXX: g_dev_orphan method does deferred destroying
  214                  * and it is possible, that other event could already
  215                  * call the orphan method. Check consumer's flags to
  216                  * do not schedule it twice.
  217                  */
  218                 if (cp->flags & G_CF_ORPHAN)
  219                         continue;
  220                 cp->flags |= G_CF_ORPHAN;
  221                 cp->geom->orphan(cp);
  222         }
  223         if (LIST_EMPTY(&pp->consumers) && wf)
  224                 g_destroy_provider(pp);
  225         else
  226                 pp->flags |= wf;
  227 #ifdef notyet
  228         cp = LIST_FIRST(&pp->consumers);
  229         if (cp != NULL)
  230                 return;
  231         if (pp->geom->flags & G_GEOM_WITHER)
  232                 g_destroy_provider(pp);
  233 #endif
  234 }
  235 
  236 static int
  237 one_event(void)
  238 {
  239         struct g_event *ep;
  240         struct g_provider *pp;
  241 
  242         g_topology_assert();
  243         mtx_lock(&g_eventlock);
  244         pp = TAILQ_FIRST(&g_doorstep);
  245         if (pp != NULL) {
  246                 G_VALID_PROVIDER(pp);
  247                 TAILQ_REMOVE(&g_doorstep, pp, orphan);
  248                 mtx_unlock(&g_eventlock);
  249                 g_orphan_register(pp);
  250                 return (1);
  251         }
  252 
  253         ep = TAILQ_FIRST(&g_events);
  254         if (ep == NULL) {
  255                 wakeup(&g_pending_events);
  256                 return (0);
  257         }
  258         ep->flag |= EV_INPROGRESS;
  259         mtx_unlock(&g_eventlock);
  260         g_topology_assert();
  261         ep->func(ep->arg, 0);
  262         g_topology_assert();
  263         mtx_lock(&g_eventlock);
  264         TSRELEASE("GEOM events");
  265         TAILQ_REMOVE(&g_events, ep, events);
  266         ep->flag &= ~EV_INPROGRESS;
  267         if (ep->flag & EV_WAKEUP) {
  268                 ep->flag |= EV_DONE;
  269                 wakeup(ep);
  270                 mtx_unlock(&g_eventlock);
  271         } else {
  272                 mtx_unlock(&g_eventlock);
  273                 g_free(ep);
  274         }
  275         return (1);
  276 }
  277 
  278 void
  279 g_run_events(void)
  280 {
  281 
  282         for (;;) {
  283                 g_topology_lock();
  284                 while (one_event())
  285                         ;
  286                 mtx_assert(&g_eventlock, MA_OWNED);
  287                 if (g_wither_work) {
  288                         g_wither_work = 0;
  289                         mtx_unlock(&g_eventlock);
  290                         g_wither_washer();
  291                         g_topology_unlock();
  292                 } else {
  293                         g_topology_unlock();
  294                         msleep(&g_wait_event, &g_eventlock, PRIBIO | PDROP,
  295                             "-", 0);
  296                 }
  297         }
  298         /* NOTREACHED */
  299 }
  300 
  301 void
  302 g_cancel_event(void *ref)
  303 {
  304         struct g_event *ep, *epn;
  305         struct g_provider *pp;
  306         u_int n;
  307 
  308         mtx_lock(&g_eventlock);
  309         TAILQ_FOREACH(pp, &g_doorstep, orphan) {
  310                 if (pp != ref)
  311                         continue;
  312                 TAILQ_REMOVE(&g_doorstep, pp, orphan);
  313                 break;
  314         }
  315         TAILQ_FOREACH_SAFE(ep, &g_events, events, epn) {
  316                 if (ep->flag & EV_INPROGRESS)
  317                         continue;
  318                 for (n = 0; n < G_N_EVENTREFS; n++) {
  319                         if (ep->ref[n] == NULL)
  320                                 break;
  321                         if (ep->ref[n] != ref)
  322                                 continue;
  323                         TSRELEASE("GEOM events");
  324                         TAILQ_REMOVE(&g_events, ep, events);
  325                         ep->func(ep->arg, EV_CANCEL);
  326                         mtx_assert(&g_eventlock, MA_OWNED);
  327                         if (ep->flag & EV_WAKEUP) {
  328                                 ep->flag |= (EV_DONE|EV_CANCELED);
  329                                 wakeup(ep);
  330                         } else {
  331                                 g_free(ep);
  332                         }
  333                         break;
  334                 }
  335         }
  336         if (TAILQ_EMPTY(&g_events))
  337                 wakeup(&g_pending_events);
  338         mtx_unlock(&g_eventlock);
  339 }
  340 
  341 struct g_event *
  342 g_alloc_event(int flag)
  343 {
  344         KASSERT(flag == M_WAITOK || flag == M_NOWAIT,
  345             ("Wrong flag to g_alloc_event"));
  346 
  347         return (g_malloc(sizeof(struct g_event), flag | M_ZERO));
  348 }
  349 
  350 static void
  351 g_post_event_ep_va(g_event_t *func, void *arg, int wuflag,
  352     struct g_event *ep, va_list ap)
  353 {
  354         void *p;
  355         u_int n;
  356 
  357         ep->flag = wuflag;
  358         for (n = 0; n < G_N_EVENTREFS; n++) {
  359                 p = va_arg(ap, void *);
  360                 if (p == NULL)
  361                         break;
  362                 g_trace(G_T_TOPOLOGY, "  ref %p", p);
  363                 ep->ref[n] = p;
  364         }
  365         KASSERT(p == NULL, ("Too many references to event"));
  366         ep->func = func;
  367         ep->arg = arg;
  368         mtx_lock(&g_eventlock);
  369         TSHOLD("GEOM events");
  370         TAILQ_INSERT_TAIL(&g_events, ep, events);
  371         mtx_unlock(&g_eventlock);
  372         wakeup(&g_wait_event);
  373         curthread->td_pflags |= TDP_GEOM;
  374         ast_sched(curthread, TDA_GEOM);
  375 }
  376 
  377 void
  378 g_post_event_ep(g_event_t *func, void *arg, struct g_event *ep, ...)
  379 {
  380         va_list ap;
  381 
  382         va_start(ap, ep);
  383         g_post_event_ep_va(func, arg, 0, ep, ap);
  384         va_end(ap);
  385 }
  386 
  387 
  388 static int
  389 g_post_event_x(g_event_t *func, void *arg, int flag, int wuflag, struct g_event **epp, va_list ap)
  390 {
  391         struct g_event *ep;
  392 
  393         g_trace(G_T_TOPOLOGY, "g_post_event_x(%p, %p, %d, %d)",
  394             func, arg, flag, wuflag);
  395         KASSERT(wuflag == 0 || wuflag == EV_WAKEUP,
  396             ("Wrong wuflag in g_post_event_x(0x%x)", wuflag));
  397         ep = g_alloc_event(flag);
  398         if (ep == NULL)
  399                 return (ENOMEM);
  400         if (epp != NULL)
  401                 *epp = ep;
  402         g_post_event_ep_va(func, arg, wuflag, ep, ap);
  403         return (0);
  404 }
  405 
  406 int
  407 g_post_event(g_event_t *func, void *arg, int flag, ...)
  408 {
  409         va_list ap;
  410         int i;
  411 
  412         KASSERT(flag == M_WAITOK || flag == M_NOWAIT,
  413             ("Wrong flag to g_post_event"));
  414         va_start(ap, flag);
  415         i = g_post_event_x(func, arg, flag, 0, NULL, ap);
  416         va_end(ap);
  417         return (i);
  418 }
  419 
  420 void
  421 g_do_wither(void)
  422 {
  423 
  424         mtx_lock(&g_eventlock);
  425         g_wither_work = 1;
  426         mtx_unlock(&g_eventlock);
  427         wakeup(&g_wait_event);
  428 }
  429 
  430 /*
  431  * XXX: It might actually be useful to call this function with topology held.
  432  * XXX: This would ensure that the event gets created before anything else
  433  * XXX: changes.  At present all users have a handle on things in some other
  434  * XXX: way, so this remains an XXX for now.
  435  */
  436 
  437 int
  438 g_waitfor_event(g_event_t *func, void *arg, int flag, ...)
  439 {
  440         va_list ap;
  441         struct g_event *ep;
  442         int error;
  443 
  444         g_topology_assert_not();
  445         KASSERT(flag == M_WAITOK || flag == M_NOWAIT,
  446             ("Wrong flag to g_post_event"));
  447         va_start(ap, flag);
  448         error = g_post_event_x(func, arg, flag, EV_WAKEUP, &ep, ap);
  449         va_end(ap);
  450         if (error)
  451                 return (error);
  452 
  453         mtx_lock(&g_eventlock);
  454         while (!(ep->flag & EV_DONE))
  455                 msleep(ep, &g_eventlock, PRIBIO, "g_waitfor_event", 0);
  456         if (ep->flag & EV_CANCELED)
  457                 error = EAGAIN;
  458         mtx_unlock(&g_eventlock);
  459 
  460         g_free(ep);
  461         return (error);
  462 }
  463 
  464 void
  465 g_event_init(void)
  466 {
  467 
  468         mtx_init(&g_eventlock, "GEOM orphanage", NULL, MTX_DEF);
  469 }
Cache object: a2f29d7ec4d08349da57949dcca5991a
[ 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.
FreeBSD/Linux Kernel Cross Reference sys/geom/geom_event.c

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