sys/kern/subr_rman.c

   1 /*
   2  * Copyright 1998 Massachusetts Institute of Technology
   3  *
   4  * Permission to use, copy, modify, and distribute this software and
   5  * its documentation for any purpose and without fee is hereby
   6  * granted, provided that both the above copyright notice and this
   7  * permission notice appear in all copies, that both the above
   8  * copyright notice and this permission notice appear in all
   9  * supporting documentation, and that the name of M.I.T. not be used
  10  * in advertising or publicity pertaining to distribution of the
  11  * software without specific, written prior permission.  M.I.T. makes
  12  * no representations about the suitability of this software for any
  13  * purpose.  It is provided "as is" without express or implied
  14  * warranty.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY M.I.T. ``AS IS''.  M.I.T. DISCLAIMS
  17  * ALL EXPRESS OR IMPLIED WARRANTIES WITH REGARD TO THIS SOFTWARE,
  18  * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  19  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT
  20  * SHALL M.I.T. BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  21  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  22  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
  23  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  24  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  25  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  26  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  *
  29  * $FreeBSD: src/sys/kern/subr_rman.c,v 1.10.2.1 2001/06/05 08:06:08 imp Exp $
  30  * $DragonFly: src/sys/kern/subr_rman.c,v 1.14 2008/01/05 14:02:38 swildner Exp $
  31  */
  32
  33 /*
  34  * The kernel resource manager.  This code is responsible for keeping track
  35  * of hardware resources which are apportioned out to various drivers.
  36  * It does not actually assign those resources, and it is not expected
  37  * that end-device drivers will call into this code directly.  Rather,
  38  * the code which implements the buses that those devices are attached to,
  39  * and the code which manages CPU resources, will call this code, and the
  40  * end-device drivers will make upcalls to that code to actually perform
  41  * the allocation.
  42  *
  43  * There are two sorts of resources managed by this code.  The first is
  44  * the more familiar array (RMAN_ARRAY) type; resources in this class
  45  * consist of a sequence of individually-allocatable objects which have
  46  * been numbered in some well-defined order.  Most of the resources
  47  * are of this type, as it is the most familiar.  The second type is
  48  * called a gauge (RMAN_GAUGE), and models fungible resources (i.e.,
  49  * resources in which each instance is indistinguishable from every
  50  * other instance).  The principal anticipated application of gauges
  51  * is in the context of power consumption, where a bus may have a specific
  52  * power budget which all attached devices share.  RMAN_GAUGE is not
  53  * implemented yet.
  54  *
  55  * For array resources, we make one simplifying assumption: two clients
  56  * sharing the same resource must use the same range of indices.  That
  57  * is to say, sharing of overlapping-but-not-identical regions is not
  58  * permitted.
  59  */
  60
  61 #include <sys/param.h>
  62 #include <sys/systm.h>
  63 #include <sys/kernel.h>
  64 #include <sys/lock.h>
  65 #include <sys/malloc.h>
  66 #include <sys/bus.h>            /* XXX debugging */
  67 #include <sys/rman.h>
  68 #include <sys/sysctl.h>
  69
  70 int     rman_debug = 0;
  71 TUNABLE_INT("debug.rman_debug", &rman_debug);
  72 SYSCTL_INT(_debug, OID_AUTO, rman_debug, CTLFLAG_RW,
  73     &rman_debug, 0, "rman debug");
  74
  75 #define DPRINTF(params) if (rman_debug) kprintf params
  76
  77 static MALLOC_DEFINE(M_RMAN, "rman", "Resource manager");
  78
  79 struct  rman_head rman_head;
  80 static  struct lwkt_token rman_tok; /* mutex to protect rman_head */
  81 static  int int_rman_activate_resource(struct rman *rm, struct resource *r,
  82                                        struct resource **whohas);
  83 static  int int_rman_deactivate_resource(struct resource *r);
  84 static  int int_rman_release_resource(struct rman *rm, struct resource *r);
  85
  86 #define CIRCLEQ_TERMCOND(var, head)     (var == (void *)&(head))
  87
  88 int
  89 rman_init(struct rman *rm)
  90 {
  91         static int once;
  92         lwkt_tokref ilock;
  93
  94         if (once == 0) {
  95                 once = 1;
  96                 TAILQ_INIT(&rman_head);
  97                 lwkt_token_init(&rman_tok);
  98         }
  99
 100         if (rm->rm_type == RMAN_UNINIT)
 101                 panic("rman_init");
 102         if (rm->rm_type == RMAN_GAUGE)
 103                 panic("implement RMAN_GAUGE");
 104
 105         CIRCLEQ_INIT(&rm->rm_list);
 106         rm->rm_slock = kmalloc(sizeof *rm->rm_slock, M_RMAN, M_NOWAIT);
 107         if (rm->rm_slock == NULL)
 108                 return ENOMEM;
 109         lwkt_token_init(rm->rm_slock);
 110
 111         lwkt_gettoken(&ilock, &rman_tok);
 112         TAILQ_INSERT_TAIL(&rman_head, rm, rm_link);
 113         lwkt_reltoken(&ilock);
 114         return 0;
 115 }
 116
 117 /*
 118  * NB: this interface is not robust against programming errors which
 119  * add multiple copies of the same region.
 120  */
 121 int
 122 rman_manage_region(struct rman *rm, u_long start, u_long end)
 123 {
 124         struct resource *r, *s;
 125         lwkt_tokref ilock;
 126
 127         DPRINTF(("rman_manage_region: <%s> request: start %#lx, end %#lx\n",
 128             rm->rm_descr, start, end));
 129         r = kmalloc(sizeof *r, M_RMAN, M_NOWAIT | M_ZERO);
 130         if (r == 0)
 131                 return ENOMEM;
 132         r->r_sharehead = 0;
 133         r->r_start = start;
 134         r->r_end = end;
 135         r->r_flags = 0;
 136         r->r_dev = 0;
 137         r->r_rm = rm;
 138
 139         lwkt_gettoken(&ilock, rm->rm_slock);
 140         for (s = CIRCLEQ_FIRST(&rm->rm_list);
 141              !CIRCLEQ_TERMCOND(s, rm->rm_list) && s->r_end < r->r_start;
 142              s = CIRCLEQ_NEXT(s, r_link))
 143                 ;
 144
 145         if (CIRCLEQ_TERMCOND(s, rm->rm_list)) {
 146                 CIRCLEQ_INSERT_TAIL(&rm->rm_list, r, r_link);
 147         } else {
 148                 CIRCLEQ_INSERT_BEFORE(&rm->rm_list, s, r, r_link);
 149         }
 150
 151         lwkt_reltoken(&ilock);
 152         return 0;
 153 }
 154
 155 int
 156 rman_fini(struct rman *rm)
 157 {
 158         struct resource *r;
 159         lwkt_tokref ilock;
 160
 161         lwkt_gettoken(&ilock, rm->rm_slock);
 162         CIRCLEQ_FOREACH(r, &rm->rm_list, r_link) {
 163                 if (r->r_flags & RF_ALLOCATED) {
 164                         lwkt_reltoken(&ilock);
 165                         return EBUSY;
 166                 }
 167         }
 168
 169         /*
 170          * There really should only be one of these if we are in this
 171          * state and the code is working properly, but it can't hurt.
 172          */
 173         while (!CIRCLEQ_EMPTY(&rm->rm_list)) {
 174                 r = CIRCLEQ_FIRST(&rm->rm_list);
 175                 CIRCLEQ_REMOVE(&rm->rm_list, r, r_link);
 176                 kfree(r, M_RMAN);
 177         }
 178         lwkt_reltoken(&ilock);
 179         /* XXX what's the point of this if we are going to free the struct? */
 180         lwkt_gettoken(&ilock, &rman_tok);
 181         TAILQ_REMOVE(&rman_head, rm, rm_link);
 182         lwkt_reltoken(&ilock);
 183         kfree(rm->rm_slock, M_RMAN);
 184
 185         return 0;
 186 }
 187
 188 struct resource *
 189 rman_reserve_resource(struct rman *rm, u_long start, u_long end, u_long count,
 190                       u_int flags, struct device *dev)
 191 {
 192         u_int   want_activate;
 193         struct  resource *r, *s, *rv;
 194         u_long  rstart, rend;
 195         lwkt_tokref ilock;
 196
 197         rv = 0;
 198
 199         DPRINTF(("rman_reserve_resource: <%s> request: [%#lx, %#lx], length "
 200                "%#lx, flags %u, device %s\n", rm->rm_descr, start, end,
 201                count, flags,
 202                dev == NULL ? "<null>" : device_get_nameunit(dev)));
 203         want_activate = (flags & RF_ACTIVE);
 204         flags &= ~RF_ACTIVE;
 205
 206         lwkt_gettoken(&ilock, rm->rm_slock);
 207
 208         for (r = CIRCLEQ_FIRST(&rm->rm_list);
 209              !CIRCLEQ_TERMCOND(r, rm->rm_list) && r->r_end < start;
 210              r = CIRCLEQ_NEXT(r, r_link))
 211                 ;
 212
 213         if (CIRCLEQ_TERMCOND(r, rm->rm_list)) {
 214                 DPRINTF(("could not find a region\n"));
 215                 goto out;
 216         }
 217
 218         /*
 219          * First try to find an acceptable totally-unshared region.
 220          */
 221         for (s = r; !CIRCLEQ_TERMCOND(s, rm->rm_list);
 222              s = CIRCLEQ_NEXT(s, r_link)) {
 223                 DPRINTF(("considering [%#lx, %#lx]\n", s->r_start, s->r_end));
 224                 if (s->r_start > end) {
 225                         DPRINTF(("s->r_start (%#lx) > end (%#lx)\n",
 226                             s->r_start, end));
 227                         break;
 228                 }
 229                 if (s->r_flags & RF_ALLOCATED) {
 230                         DPRINTF(("region is allocated\n"));
 231                         continue;
 232                 }
 233                 rstart = max(s->r_start, start);
 234                 rstart = (rstart + ((1ul << RF_ALIGNMENT(flags))) - 1) &
 235                     ~((1ul << RF_ALIGNMENT(flags)) - 1);
 236                 rend = min(s->r_end, max(start + count, end));
 237                 DPRINTF(("truncated region: [%#lx, %#lx]; size %#lx (requested %#lx)\n",
 238                        rstart, rend, (rend - rstart + 1), count));
 239
 240                 if ((rend - rstart + 1) >= count) {
 241                         DPRINTF(("candidate region: [%#lx, %#lx], size %#lx\n",
 242                                rstart, rend, (rend - rstart + 1)));
 243                         if ((s->r_end - s->r_start + 1) == count) {
 244                                 DPRINTF(("candidate region is entire chunk\n"));
 245                                 rv = s;
 246                                 rv->r_flags |= RF_ALLOCATED | flags;
 247                                 rv->r_dev = dev;
 248                                 goto out;
 249                         }
 250
 251                         /*
 252                          * If s->r_start < rstart and
 253                          *    s->r_end > rstart + count - 1, then
 254                          * we need to split the region into three pieces
 255                          * (the middle one will get returned to the user).
 256                          * Otherwise, we are allocating at either the
 257                          * beginning or the end of s, so we only need to
 258                          * split it in two.  The first case requires
 259                          * two new allocations; the second requires but one.
 260                          */
 261                         rv = kmalloc(sizeof *rv, M_RMAN, M_NOWAIT | M_ZERO);
 262                         if (rv == 0)
 263                                 goto out;
 264                         rv->r_start = rstart;
 265                         rv->r_end = rstart + count - 1;
 266                         rv->r_flags = flags | RF_ALLOCATED;
 267                         rv->r_dev = dev;
 268                         rv->r_sharehead = 0;
 269                         rv->r_rm = rm;
 270
 271                         if (s->r_start < rv->r_start && s->r_end > rv->r_end) {
 272                                 DPRINTF(("splitting region in three parts: "
 273                                        "[%#lx, %#lx]; [%#lx, %#lx]; [%#lx, %#lx]\n",
 274                                        s->r_start, rv->r_start - 1,
 275                                        rv->r_start, rv->r_end,
 276                                        rv->r_end + 1, s->r_end));
 277                                 /*
 278                                  * We are allocating in the middle.
 279                                  */
 280                                 r = kmalloc(sizeof *r, M_RMAN,
 281                                     M_NOWAIT | M_ZERO);
 282                                 if (r == 0) {
 283                                         kfree(rv, M_RMAN);
 284                                         rv = 0;
 285                                         goto out;
 286                                 }
 287                                 r->r_start = rv->r_end + 1;
 288                                 r->r_end = s->r_end;
 289                                 r->r_flags = s->r_flags;
 290                                 r->r_dev = 0;
 291                                 r->r_sharehead = 0;
 292                                 r->r_rm = rm;
 293                                 s->r_end = rv->r_start - 1;
 294                                 CIRCLEQ_INSERT_AFTER(&rm->rm_list, s, rv,
 295                                                      r_link);
 296                                 CIRCLEQ_INSERT_AFTER(&rm->rm_list, rv, r,
 297                                                      r_link);
 298                         } else if (s->r_start == rv->r_start) {
 299                                 DPRINTF(("allocating from the beginning\n"));
 300                                 /*
 301                                  * We are allocating at the beginning.
 302                                  */
 303                                 s->r_start = rv->r_end + 1;
 304                                 CIRCLEQ_INSERT_BEFORE(&rm->rm_list, s, rv,
 305                                                       r_link);
 306                         } else {
 307                                 DPRINTF(("allocating at the end\n"));
 308                                 /*
 309                                  * We are allocating at the end.
 310                                  */
 311                                 s->r_end = rv->r_start - 1;
 312                                 CIRCLEQ_INSERT_AFTER(&rm->rm_list, s, rv,
 313                                                      r_link);
 314                         }
 315                         goto out;
 316                 }
 317         }
 318
 319         /*
 320          * Now find an acceptable shared region, if the client's requirements
 321          * allow sharing.  By our implementation restriction, a candidate
 322          * region must match exactly by both size and sharing type in order
 323          * to be considered compatible with the client's request.  (The
 324          * former restriction could probably be lifted without too much
 325          * additional work, but this does not seem warranted.)
 326          */
 327         DPRINTF(("no unshared regions found\n"));
 328         if ((flags & (RF_SHAREABLE | RF_TIMESHARE)) == 0)
 329                 goto out;
 330
 331         for (s = r; !CIRCLEQ_TERMCOND(s, rm->rm_list);
 332              s = CIRCLEQ_NEXT(s, r_link)) {
 333                 if (s->r_start > end)
 334                         break;
 335                 if ((s->r_flags & flags) != flags)
 336                         continue;
 337                 rstart = max(s->r_start, start);
 338                 rend = min(s->r_end, max(start + count, end));
 339                 if (s->r_start >= start && s->r_end <= end
 340                     && (s->r_end - s->r_start + 1) == count) {
 341                         rv = kmalloc(sizeof *rv, M_RMAN, M_NOWAIT | M_ZERO);
 342                         if (rv == 0)
 343                                 goto out;
 344                         rv->r_start = s->r_start;
 345                         rv->r_end = s->r_end;
 346                         rv->r_flags = s->r_flags &
 347                                 (RF_ALLOCATED | RF_SHAREABLE | RF_TIMESHARE);
 348                         rv->r_dev = dev;
 349                         rv->r_rm = rm;
 350                         if (s->r_sharehead == 0) {
 351                                 s->r_sharehead = kmalloc(sizeof *s->r_sharehead,
 352                                                         M_RMAN,
 353                                                         M_NOWAIT | M_ZERO);
 354                                 if (s->r_sharehead == 0) {
 355                                         kfree(rv, M_RMAN);
 356                                         rv = 0;
 357                                         goto out;
 358                                 }
 359                                 LIST_INIT(s->r_sharehead);
 360                                 LIST_INSERT_HEAD(s->r_sharehead, s,
 361                                                  r_sharelink);
 362                                 s->r_flags |= RF_FIRSTSHARE;
 363                         }
 364                         rv->r_sharehead = s->r_sharehead;
 365                         LIST_INSERT_HEAD(s->r_sharehead, rv, r_sharelink);
 366                         goto out;
 367                 }
 368         }
 369
 370         /*
 371          * We couldn't find anything.
 372          */
 373 out:
 374         /*
 375          * If the user specified RF_ACTIVE in the initial flags,
 376          * which is reflected in `want_activate', we attempt to atomically
 377          * activate the resource.  If this fails, we release the resource
 378          * and indicate overall failure.  (This behavior probably doesn't
 379          * make sense for RF_TIMESHARE-type resources.)
 380          */
 381         if (rv && want_activate) {
 382                 struct resource *whohas;
 383                 if (int_rman_activate_resource(rm, rv, &whohas)) {
 384                         int_rman_release_resource(rm, rv);
 385                         rv = 0;
 386                 }
 387         }
 388         lwkt_reltoken(&ilock);
 389         return (rv);
 390 }
 391
 392 static int
 393 int_rman_activate_resource(struct rman *rm, struct resource *r,
 394                            struct resource **whohas)
 395 {
 396         struct resource *s;
 397         int ok;
 398
 399         /*
 400          * If we are not timesharing, then there is nothing much to do.
 401          * If we already have the resource, then there is nothing at all to do.
 402          * If we are not on a sharing list with anybody else, then there is
 403          * little to do.
 404          */
 405         if ((r->r_flags & RF_TIMESHARE) == 0
 406             || (r->r_flags & RF_ACTIVE) != 0
 407             || r->r_sharehead == 0) {
 408                 r->r_flags |= RF_ACTIVE;
 409                 return 0;
 410         }
 411
 412         ok = 1;
 413         for (s = LIST_FIRST(r->r_sharehead); s && ok;
 414              s = LIST_NEXT(s, r_sharelink)) {
 415                 if ((s->r_flags & RF_ACTIVE) != 0) {
 416                         ok = 0;
 417                         *whohas = s;
 418                 }
 419         }
 420         if (ok) {
 421                 r->r_flags |= RF_ACTIVE;
 422                 return 0;
 423         }
 424         return EBUSY;
 425 }
 426
 427 int
 428 rman_activate_resource(struct resource *r)
 429 {
 430         int rv;
 431         struct resource *whohas;
 432         lwkt_tokref ilock;
 433         struct rman *rm;
 434
 435         rm = r->r_rm;
 436         lwkt_gettoken(&ilock, rm->rm_slock);
 437         rv = int_rman_activate_resource(rm, r, &whohas);
 438         lwkt_reltoken(&ilock);
 439         return rv;
 440 }
 441
 442 #if 0
 443
 444 /* XXX */
 445 int
 446 rman_await_resource(struct resource *r, lwkt_tokref_t ilock, int slpflags, int timo)
 447 {
 448         int     rv;
 449         struct  resource *whohas;
 450         struct  rman *rm;
 451
 452         rm = r->r_rm;
 453         for (;;) {
 454                 lwkt_gettoken(ilock, rm->rm_slock);
 455                 rv = int_rman_activate_resource(rm, r, &whohas);
 456                 if (rv != EBUSY)
 457                         return (rv);    /* returns with ilock held */
 458
 459                 if (r->r_sharehead == 0)
 460                         panic("rman_await_resource");
 461                 /*
 462                  * A critical section will hopefully will prevent a race
 463                  * between lwkt_reltoken and tsleep where a process
 464                  * could conceivably get in and release the resource
 465                  * before we have a chance to sleep on it. YYY
 466                  */
 467                 crit_enter();
 468                 whohas->r_flags |= RF_WANTED;
 469                 rv = tsleep(r->r_sharehead, slpflags, "rmwait", timo);
 470                 if (rv) {
 471                         lwkt_reltoken(ilock);
 472                         crit_exit();
 473                         return rv;
 474                 }
 475                 crit_exit();
 476         }
 477 }
 478
 479 #endif
 480
 481 static int
 482 int_rman_deactivate_resource(struct resource *r)
 483 {
 484         struct  rman *rm;
 485
 486         rm = r->r_rm;
 487         r->r_flags &= ~RF_ACTIVE;
 488         if (r->r_flags & RF_WANTED) {
 489                 r->r_flags &= ~RF_WANTED;
 490                 wakeup(r->r_sharehead);
 491         }
 492         return 0;
 493 }
 494
 495 int
 496 rman_deactivate_resource(struct resource *r)
 497 {
 498         lwkt_tokref ilock;
 499         struct rman *rm;
 500
 501         rm = r->r_rm;
 502         lwkt_gettoken(&ilock, rm->rm_slock);
 503         int_rman_deactivate_resource(r);
 504         lwkt_reltoken(&ilock);
 505         return 0;
 506 }
 507
 508 static int
 509 int_rman_release_resource(struct rman *rm, struct resource *r)
 510 {
 511         struct  resource *s, *t;
 512
 513         if (r->r_flags & RF_ACTIVE)
 514                 int_rman_deactivate_resource(r);
 515
 516         /*
 517          * Check for a sharing list first.  If there is one, then we don't
 518          * have to think as hard.
 519          */
 520         if (r->r_sharehead) {
 521                 /*
 522                  * If a sharing list exists, then we know there are at
 523                  * least two sharers.
 524                  *
 525                  * If we are in the main circleq, appoint someone else.
 526                  */
 527                 LIST_REMOVE(r, r_sharelink);
 528                 s = LIST_FIRST(r->r_sharehead);
 529                 if (r->r_flags & RF_FIRSTSHARE) {
 530                         s->r_flags |= RF_FIRSTSHARE;
 531                         CIRCLEQ_INSERT_BEFORE(&rm->rm_list, r, s, r_link);
 532                         CIRCLEQ_REMOVE(&rm->rm_list, r, r_link);
 533                 }
 534
 535                 /*
 536                  * Make sure that the sharing list goes away completely
 537                  * if the resource is no longer being shared at all.
 538                  */
 539                 if (LIST_NEXT(s, r_sharelink) == 0) {
 540                         kfree(s->r_sharehead, M_RMAN);
 541                         s->r_sharehead = 0;
 542                         s->r_flags &= ~RF_FIRSTSHARE;
 543                 }
 544                 goto out;
 545         }
 546
 547         /*
 548          * Look at the adjacent resources in the list and see if our
 549          * segment can be merged with any of them.
 550          */
 551         s = CIRCLEQ_PREV(r, r_link);
 552         t = CIRCLEQ_NEXT(r, r_link);
 553
 554         if (s != (void *)&rm->rm_list && (s->r_flags & RF_ALLOCATED) == 0
 555             && t != (void *)&rm->rm_list && (t->r_flags & RF_ALLOCATED) == 0) {
 556                 /*
 557                  * Merge all three segments.
 558                  */
 559                 s->r_end = t->r_end;
 560                 CIRCLEQ_REMOVE(&rm->rm_list, r, r_link);
 561                 CIRCLEQ_REMOVE(&rm->rm_list, t, r_link);
 562                 kfree(t, M_RMAN);
 563         } else if (s != (void *)&rm->rm_list
 564                    && (s->r_flags & RF_ALLOCATED) == 0) {
 565                 /*
 566                  * Merge previous segment with ours.
 567                  */
 568                 s->r_end = r->r_end;
 569                 CIRCLEQ_REMOVE(&rm->rm_list, r, r_link);
 570         } else if (t != (void *)&rm->rm_list
 571                    && (t->r_flags & RF_ALLOCATED) == 0) {
 572                 /*
 573                  * Merge next segment with ours.
 574                  */
 575                 t->r_start = r->r_start;
 576                 CIRCLEQ_REMOVE(&rm->rm_list, r, r_link);
 577         } else {
 578                 /*
 579                  * At this point, we know there is nothing we
 580                  * can potentially merge with, because on each
 581                  * side, there is either nothing there or what is
 582                  * there is still allocated.  In that case, we don't
 583                  * want to remove r from the list; we simply want to
 584                  * change it to an unallocated region and return
 585                  * without freeing anything.
 586                  */
 587                 r->r_flags &= ~RF_ALLOCATED;
 588                 return 0;
 589         }
 590
 591 out:
 592         kfree(r, M_RMAN);
 593         return 0;
 594 }
 595
 596 int
 597 rman_release_resource(struct resource *r)
 598 {
 599         struct  rman *rm = r->r_rm;
 600         lwkt_tokref ilock;
 601         int     rv;
 602
 603         lwkt_gettoken(&ilock, rm->rm_slock);
 604         rv = int_rman_release_resource(rm, r);
 605         lwkt_reltoken(&ilock);
 606         return (rv);
 607 }
 608
 609 uint32_t
 610 rman_make_alignment_flags(uint32_t size)
 611 {
 612         int     i;
 613
 614         /*
 615          * Find the hightest bit set, and add one if more than one bit
 616          * set.  We're effectively computing the ceil(log2(size)) here.
 617          */
 618         for (i = 32; i > 0; i--)
 619                 if ((1 << i) & size)
 620                         break;
 621         if (~(1 << i) & size)
 622                 i++;
 623
 624         return(RF_ALIGNMENT_LOG2(i));
 625 }