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


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FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_osd.c

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    1 /*-
    2  * Copyright (c) 2007 Pawel Jakub Dawidek <pjd@FreeBSD.org>
    3  * All rights reserved.
    4  *
    5  * Redistribution and use in source and binary forms, with or without
    6  * modification, are permitted provided that the following conditions
    7  * are met:
    8  * 1. Redistributions of source code must retain the above copyright
    9  *    notice, this list of conditions and the following disclaimer.
   10  * 2. Redistributions in binary form must reproduce the above copyright
   11  *    notice, this list of conditions and the following disclaimer in the
   12  *    documentation and/or other materials provided with the distribution.
   13  *
   14  * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
   15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
   18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   24  * SUCH DAMAGE.
   25  */
   26 
   27 #include <sys/cdefs.h>
   28 __FBSDID("$FreeBSD: stable/10/sys/kern/kern_osd.c 298834 2016-04-30 04:01:22Z jamie $");
   29 
   30 #include <sys/param.h>
   31 #include <sys/kernel.h>
   32 #include <sys/systm.h>
   33 #include <sys/sysctl.h>
   34 #include <sys/errno.h>
   35 #include <sys/jail.h>
   36 #include <sys/malloc.h>
   37 #include <sys/lock.h>
   38 #include <sys/mutex.h>
   39 #include <sys/rmlock.h>
   40 #include <sys/sx.h>
   41 #include <sys/queue.h>
   42 #include <sys/proc.h>
   43 #include <sys/osd.h>
   44 
   45 /* OSD (Object Specific Data) */
   46 
   47 /*
   48  * Lock key:
   49  *  (m) osd_module_lock
   50  *  (o) osd_object_lock
   51  *  (l) osd_list_lock
   52  */
   53 struct osd_master {
   54         struct sx                osd_module_lock;
   55         struct rmlock            osd_object_lock;
   56         struct mtx               osd_list_lock;
   57         LIST_HEAD(, osd)         osd_list;              /* (l) */
   58         osd_destructor_t        *osd_destructors;       /* (o) */
   59         osd_method_t            *osd_methods;           /* (m) */
   60         u_int                    osd_ntslots;           /* (m) */
   61         const u_int              osd_nmethods;
   62 };
   63 
   64 static MALLOC_DEFINE(M_OSD, "osd", "Object Specific Data");
   65 
   66 static int osd_debug = 0;
   67 TUNABLE_INT("debug.osd", &osd_debug);
   68 SYSCTL_INT(_debug, OID_AUTO, osd, CTLFLAG_RW, &osd_debug, 0, "OSD debug level");
   69 
   70 #define OSD_DEBUG(...)  do {                                            \
   71         if (osd_debug) {                                                \
   72                 printf("OSD (%s:%u): ", __func__, __LINE__);            \
   73                 printf(__VA_ARGS__);                                    \
   74                 printf("\n");                                           \
   75         }                                                               \
   76 } while (0)
   77 
   78 static void do_osd_del(u_int type, struct osd *osd, u_int slot,
   79     int list_locked);
   80 
   81 /*
   82  * List of objects with OSD.
   83  */
   84 struct osd_master osdm[OSD_LAST + 1] = {
   85         [OSD_JAIL] = { .osd_nmethods = PR_MAXMETHOD },
   86 };
   87 
   88 static void
   89 osd_default_destructor(void *value __unused)
   90 {
   91         /* Do nothing. */
   92 }
   93 
   94 int
   95 osd_register(u_int type, osd_destructor_t destructor, osd_method_t *methods)
   96 {
   97         void *newptr;
   98         u_int i, m;
   99 
  100         KASSERT(type >= OSD_FIRST && type <= OSD_LAST, ("Invalid type."));
  101 
  102         /*
  103          * If no destructor is given, use default one. We need to use some
  104          * destructor, because NULL destructor means unused slot.
  105          */
  106         if (destructor == NULL)
  107                 destructor = osd_default_destructor;
  108 
  109         sx_xlock(&osdm[type].osd_module_lock);
  110         /*
  111          * First, we try to find unused slot.
  112          */
  113         for (i = 0; i < osdm[type].osd_ntslots; i++) {
  114                 if (osdm[type].osd_destructors[i] == NULL) {
  115                         OSD_DEBUG("Unused slot found (type=%u, slot=%u).",
  116                             type, i);
  117                         break;
  118                 }
  119         }
  120         /*
  121          * If no unused slot was found, allocate one.
  122          */
  123         if (i == osdm[type].osd_ntslots) {
  124                 osdm[type].osd_ntslots++;
  125                 if (osdm[type].osd_nmethods != 0)
  126                         osdm[type].osd_methods = realloc(osdm[type].osd_methods,
  127                             sizeof(osd_method_t) * osdm[type].osd_ntslots *
  128                             osdm[type].osd_nmethods, M_OSD, M_WAITOK);
  129                 newptr = malloc(sizeof(osd_destructor_t) *
  130                     osdm[type].osd_ntslots, M_OSD, M_WAITOK);
  131                 rm_wlock(&osdm[type].osd_object_lock);
  132                 bcopy(osdm[type].osd_destructors, newptr,
  133                     sizeof(osd_destructor_t) * i);
  134                 free(osdm[type].osd_destructors, M_OSD);
  135                 osdm[type].osd_destructors = newptr;
  136                 rm_wunlock(&osdm[type].osd_object_lock);
  137                 OSD_DEBUG("New slot allocated (type=%u, slot=%u).",
  138                     type, i + 1);
  139         }
  140 
  141         osdm[type].osd_destructors[i] = destructor;
  142         if (osdm[type].osd_nmethods != 0) {
  143                 for (m = 0; m < osdm[type].osd_nmethods; m++)
  144                         osdm[type].osd_methods[i * osdm[type].osd_nmethods + m]
  145                             = methods != NULL ? methods[m] : NULL;
  146         }
  147         sx_xunlock(&osdm[type].osd_module_lock);
  148         return (i + 1);
  149 }
  150 
  151 void
  152 osd_deregister(u_int type, u_int slot)
  153 {
  154         struct osd *osd, *tosd;
  155 
  156         KASSERT(type >= OSD_FIRST && type <= OSD_LAST, ("Invalid type."));
  157         KASSERT(slot > 0, ("Invalid slot."));
  158         KASSERT(osdm[type].osd_destructors[slot - 1] != NULL, ("Unused slot."));
  159 
  160         sx_xlock(&osdm[type].osd_module_lock);
  161         rm_wlock(&osdm[type].osd_object_lock);
  162         /*
  163          * Free all OSD for the given slot.
  164          */
  165         mtx_lock(&osdm[type].osd_list_lock);
  166         LIST_FOREACH_SAFE(osd, &osdm[type].osd_list, osd_next, tosd)
  167                 do_osd_del(type, osd, slot, 1);
  168         mtx_unlock(&osdm[type].osd_list_lock);
  169         /*
  170          * Set destructor to NULL to free the slot.
  171          */
  172         osdm[type].osd_destructors[slot - 1] = NULL;
  173         if (slot == osdm[type].osd_ntslots) {
  174                 osdm[type].osd_ntslots--;
  175                 osdm[type].osd_destructors = realloc(osdm[type].osd_destructors,
  176                     sizeof(osd_destructor_t) * osdm[type].osd_ntslots, M_OSD,
  177                     M_NOWAIT | M_ZERO);
  178                 if (osdm[type].osd_nmethods != 0)
  179                         osdm[type].osd_methods = realloc(osdm[type].osd_methods,
  180                             sizeof(osd_method_t) * osdm[type].osd_ntslots *
  181                             osdm[type].osd_nmethods, M_OSD, M_NOWAIT | M_ZERO);
  182                 /*
  183                  * We always reallocate to smaller size, so we assume it will
  184                  * always succeed.
  185                  */
  186                 KASSERT(osdm[type].osd_destructors != NULL &&
  187                     (osdm[type].osd_nmethods == 0 ||
  188                      osdm[type].osd_methods != NULL), ("realloc() failed"));
  189                 OSD_DEBUG("Deregistration of the last slot (type=%u, slot=%u).",
  190                     type, slot);
  191         } else {
  192                 OSD_DEBUG("Slot deregistration (type=%u, slot=%u).",
  193                     type, slot);
  194         }
  195         rm_wunlock(&osdm[type].osd_object_lock);
  196         sx_xunlock(&osdm[type].osd_module_lock);
  197 }
  198 
  199 int
  200 osd_set(u_int type, struct osd *osd, u_int slot, void *value)
  201 {
  202 
  203         return (osd_set_reserved(type, osd, slot, NULL, value));
  204 }
  205 
  206 void *
  207 osd_reserve(u_int slot)
  208 {
  209 
  210         KASSERT(slot > 0, ("Invalid slot."));
  211 
  212         OSD_DEBUG("Reserving slot array (slot=%u).", slot);
  213         return (malloc(sizeof(void *) * slot, M_OSD, M_WAITOK | M_ZERO));
  214 }
  215 
  216 int
  217 osd_set_reserved(u_int type, struct osd *osd, u_int slot, void *rsv,
  218     void *value)
  219 {
  220         struct rm_priotracker tracker;
  221 
  222         KASSERT(type >= OSD_FIRST && type <= OSD_LAST, ("Invalid type."));
  223         KASSERT(slot > 0, ("Invalid slot."));
  224         KASSERT(osdm[type].osd_destructors[slot - 1] != NULL, ("Unused slot."));
  225 
  226         rm_rlock(&osdm[type].osd_object_lock, &tracker);
  227         if (slot > osd->osd_nslots) {
  228                 void *newptr;
  229 
  230                 if (value == NULL) {
  231                         OSD_DEBUG(
  232                             "Not allocating null slot (type=%u, slot=%u).",
  233                             type, slot);
  234                         rm_runlock(&osdm[type].osd_object_lock, &tracker);
  235                         if (rsv)
  236                                 osd_free_reserved(rsv);
  237                         return (0);
  238                 }
  239 
  240                 /*
  241                  * Too few slots allocated here, so we need to extend or create
  242                  * the array.
  243                  */
  244                 if (rsv) {
  245                         /*
  246                          * Use the reserve passed in (assumed to be
  247                          * the right size).
  248                          */
  249                         newptr = rsv;
  250                         if (osd->osd_nslots != 0) {
  251                                 memcpy(newptr, osd->osd_slots,
  252                                     sizeof(void *) * osd->osd_nslots);
  253                                 free(osd->osd_slots, M_OSD);
  254                         }
  255                 } else {
  256                         newptr = realloc(osd->osd_slots, sizeof(void *) * slot,
  257                             M_OSD, M_NOWAIT | M_ZERO);
  258                         if (newptr == NULL) {
  259                                 rm_runlock(&osdm[type].osd_object_lock,
  260                                     &tracker);
  261                                 return (ENOMEM);
  262                         }
  263                 }
  264                 if (osd->osd_nslots == 0) {
  265                         /*
  266                          * First OSD for this object, so we need to put it
  267                          * onto the list.
  268                          */
  269                         mtx_lock(&osdm[type].osd_list_lock);
  270                         LIST_INSERT_HEAD(&osdm[type].osd_list, osd, osd_next);
  271                         mtx_unlock(&osdm[type].osd_list_lock);
  272                         OSD_DEBUG("Setting first slot (type=%u).", type);
  273                 } else
  274                         OSD_DEBUG("Growing slots array (type=%u).", type);
  275                 osd->osd_slots = newptr;
  276                 osd->osd_nslots = slot;
  277         } else if (rsv)
  278                 osd_free_reserved(rsv);
  279         OSD_DEBUG("Setting slot value (type=%u, slot=%u, value=%p).", type,
  280             slot, value);
  281         osd->osd_slots[slot - 1] = value;
  282         rm_runlock(&osdm[type].osd_object_lock, &tracker);
  283         return (0);
  284 }
  285 
  286 void
  287 osd_free_reserved(void *rsv)
  288 {
  289 
  290         OSD_DEBUG("Discarding reserved slot array.");
  291         free(rsv, M_OSD);
  292 }
  293 
  294 void *
  295 osd_get(u_int type, struct osd *osd, u_int slot)
  296 {
  297         struct rm_priotracker tracker;
  298         void *value;
  299 
  300         KASSERT(type >= OSD_FIRST && type <= OSD_LAST, ("Invalid type."));
  301         KASSERT(slot > 0, ("Invalid slot."));
  302         KASSERT(osdm[type].osd_destructors[slot - 1] != NULL, ("Unused slot."));
  303 
  304         rm_rlock(&osdm[type].osd_object_lock, &tracker);
  305         if (slot > osd->osd_nslots) {
  306                 value = NULL;
  307                 OSD_DEBUG("Slot doesn't exist (type=%u, slot=%u).", type, slot);
  308         } else {
  309                 value = osd->osd_slots[slot - 1];
  310                 OSD_DEBUG("Returning slot value (type=%u, slot=%u, value=%p).",
  311                     type, slot, value);
  312         }
  313         rm_runlock(&osdm[type].osd_object_lock, &tracker);
  314         return (value);
  315 }
  316 
  317 void
  318 osd_del(u_int type, struct osd *osd, u_int slot)
  319 {
  320         struct rm_priotracker tracker;
  321 
  322         rm_rlock(&osdm[type].osd_object_lock, &tracker);
  323         do_osd_del(type, osd, slot, 0);
  324         rm_runlock(&osdm[type].osd_object_lock, &tracker);
  325 }
  326 
  327 static void
  328 do_osd_del(u_int type, struct osd *osd, u_int slot, int list_locked)
  329 {
  330         int i;
  331 
  332         KASSERT(type >= OSD_FIRST && type <= OSD_LAST, ("Invalid type."));
  333         KASSERT(slot > 0, ("Invalid slot."));
  334         KASSERT(osdm[type].osd_destructors[slot - 1] != NULL, ("Unused slot."));
  335 
  336         OSD_DEBUG("Deleting slot (type=%u, slot=%u).", type, slot);
  337 
  338         if (slot > osd->osd_nslots) {
  339                 OSD_DEBUG("Slot doesn't exist (type=%u, slot=%u).", type, slot);
  340                 return;
  341         }
  342         if (osd->osd_slots[slot - 1] != NULL) {
  343                 osdm[type].osd_destructors[slot - 1](osd->osd_slots[slot - 1]);
  344                 osd->osd_slots[slot - 1] = NULL;
  345         }
  346         for (i = osd->osd_nslots - 1; i >= 0; i--) {
  347                 if (osd->osd_slots[i] != NULL) {
  348                         OSD_DEBUG("Slot still has a value (type=%u, slot=%u).",
  349                             type, i + 1);
  350                         break;
  351                 }
  352         }
  353         if (i == -1) {
  354                 /* No values left for this object. */
  355                 OSD_DEBUG("No more slots left (type=%u).", type);
  356                 if (!list_locked)
  357                         mtx_lock(&osdm[type].osd_list_lock);
  358                 LIST_REMOVE(osd, osd_next);
  359                 if (!list_locked)
  360                         mtx_unlock(&osdm[type].osd_list_lock);
  361                 free(osd->osd_slots, M_OSD);
  362                 osd->osd_slots = NULL;
  363                 osd->osd_nslots = 0;
  364         } else if (slot == osd->osd_nslots) {
  365                 /* This was the last slot. */
  366                 osd->osd_slots = realloc(osd->osd_slots,
  367                     sizeof(void *) * (i + 1), M_OSD, M_NOWAIT | M_ZERO);
  368                 /*
  369                  * We always reallocate to smaller size, so we assume it will
  370                  * always succeed.
  371                  */
  372                 KASSERT(osd->osd_slots != NULL, ("realloc() failed"));
  373                 osd->osd_nslots = i + 1;
  374                 OSD_DEBUG("Reducing slots array to %u (type=%u).",
  375                     osd->osd_nslots, type);
  376         }
  377 }
  378 
  379 int
  380 osd_call(u_int type, u_int method, void *obj, void *data)
  381 {
  382         osd_method_t methodfun;
  383         int error, i;
  384 
  385         KASSERT(type >= OSD_FIRST && type <= OSD_LAST, ("Invalid type."));
  386         KASSERT(method < osdm[type].osd_nmethods, ("Invalid method."));
  387 
  388         /*
  389          * Call this method for every slot that defines it, stopping if an
  390          * error is encountered.
  391          */
  392         error = 0;
  393         sx_slock(&osdm[type].osd_module_lock);
  394         for (i = 0; i < osdm[type].osd_ntslots; i++) {
  395                 methodfun = osdm[type].osd_methods[i * osdm[type].osd_nmethods +
  396                     method];
  397                 if (methodfun != NULL && (error = methodfun(obj, data)) != 0)
  398                         break;
  399         }
  400         sx_sunlock(&osdm[type].osd_module_lock);
  401         return (error);
  402 }
  403 
  404 void
  405 osd_exit(u_int type, struct osd *osd)
  406 {
  407         struct rm_priotracker tracker;
  408         u_int i;
  409 
  410         KASSERT(type >= OSD_FIRST && type <= OSD_LAST, ("Invalid type."));
  411 
  412         if (osd->osd_nslots == 0) {
  413                 KASSERT(osd->osd_slots == NULL, ("Non-null osd_slots."));
  414                 /* No OSD attached, just leave. */
  415                 return;
  416         }
  417 
  418         rm_rlock(&osdm[type].osd_object_lock, &tracker);
  419         for (i = 1; i <= osd->osd_nslots; i++) {
  420                 if (osdm[type].osd_destructors[i - 1] != NULL)
  421                         do_osd_del(type, osd, i, 0);
  422                 else
  423                         OSD_DEBUG("Unused slot (type=%u, slot=%u).", type, i);
  424         }
  425         rm_runlock(&osdm[type].osd_object_lock, &tracker);
  426         OSD_DEBUG("Object exit (type=%u).", type);
  427 }
  428 
  429 static void
  430 osd_init(void *arg __unused)
  431 {
  432         u_int i;
  433 
  434         for (i = OSD_FIRST; i <= OSD_LAST; i++) {
  435                 sx_init(&osdm[i].osd_module_lock, "osd_module");
  436                 rm_init(&osdm[i].osd_object_lock, "osd_object");
  437                 mtx_init(&osdm[i].osd_list_lock, "osd_list", NULL, MTX_DEF);
  438                 LIST_INIT(&osdm[i].osd_list);
  439                 osdm[i].osd_destructors = NULL;
  440                 osdm[i].osd_ntslots = 0;
  441                 osdm[i].osd_methods = NULL;
  442         }
  443 }
  444 SYSINIT(osd, SI_SUB_LOCK, SI_ORDER_ANY, osd_init, NULL);

Cache object: f7e48d9e171a4be899476a2722bc96a3


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