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 1.12 2007/05/20 07:43:24 y0netan1 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
  69 #ifdef RMAN_DEBUG
  70 #define DPRINTF(params) kprintf params
  71 #else
  72 #define DPRINTF(params)
  73 #endif
  74
  75 static MALLOC_DEFINE(M_RMAN, "rman", "Resource manager");
  76
  77 struct  rman_head rman_head;
  78 static  struct lwkt_token rman_tok; /* mutex to protect rman_head */
  79 static  int int_rman_activate_resource(struct rman *rm, struct resource *r,
  80                                        struct resource **whohas);
  81 static  int int_rman_deactivate_resource(struct resource *r);
  82 static  int int_rman_release_resource(struct rman *rm, struct resource *r);
  83
  84 #define CIRCLEQ_TERMCOND(var, head)     (var == (void *)&(head))
  85
  86 int
  87 rman_init(struct rman *rm)
  88 {
  89         static int once;
  90         lwkt_tokref ilock;
  91
  92         if (once == 0) {
  93                 once = 1;
  94                 TAILQ_INIT(&rman_head);
  95                 lwkt_token_init(&rman_tok);
  96         }
  97
  98         if (rm->rm_type == RMAN_UNINIT)
  99                 panic("rman_init");
 100         if (rm->rm_type == RMAN_GAUGE)
 101                 panic("implement RMAN_GAUGE");
 102
 103         CIRCLEQ_INIT(&rm->rm_list);
 104         rm->rm_slock = kmalloc(sizeof *rm->rm_slock, M_RMAN, M_NOWAIT);
 105         if (rm->rm_slock == NULL)
 106                 return ENOMEM;
 107         lwkt_token_init(rm->rm_slock);
 108
 109         lwkt_gettoken(&ilock, &rman_tok);
 110         TAILQ_INSERT_TAIL(&rman_head, rm, rm_link);
 111         lwkt_reltoken(&ilock);
 112         return 0;
 113 }
 114
 115 /*
 116  * NB: this interface is not robust against programming errors which
 117  * add multiple copies of the same region.
 118  */
 119 int
 120 rman_manage_region(struct rman *rm, u_long start, u_long end)
 121 {
 122         struct resource *r, *s;
 123         lwkt_tokref ilock;
 124
 125         DPRINTF(("rman_manage_region: <%s> request: start %#lx, end %#lx\n",
 126             rm->rm_descr, start, end));
 127         r = kmalloc(sizeof *r, M_RMAN, M_NOWAIT);
 128         if (r == 0)
 129                 return ENOMEM;
 130         bzero(r, sizeof *r);
 131         r->r_sharehead = 0;
 132         r->r_start = start;
 133         r->r_end = end;
 134         r->r_flags = 0;
 135         r->r_dev = 0;
 136         r->r_rm = rm;
 137
 138         lwkt_gettoken(&ilock, rm->rm_slock);
 139         for (s = CIRCLEQ_FIRST(&rm->rm_list);
 140              !CIRCLEQ_TERMCOND(s, rm->rm_list) && s->r_end < r->r_start;
 141              s = CIRCLEQ_NEXT(s, r_link))
 142                 ;
 143
 144         if (CIRCLEQ_TERMCOND(s, rm->rm_list)) {
 145                 CIRCLEQ_INSERT_TAIL(&rm->rm_list, r, r_link);
 146         } else {
 147                 CIRCLEQ_INSERT_BEFORE(&rm->rm_list, s, r, r_link);
 148         }
 149
 150         lwkt_reltoken(&ilock);
 151         return 0;
 152 }
 153
 154 int
 155 rman_fini(struct rman *rm)
 156 {
 157         struct resource *r;
 158         lwkt_tokref ilock;
 159
 160         lwkt_gettoken(&ilock, rm->rm_slock);
 161         CIRCLEQ_FOREACH(r, &rm->rm_list, r_link) {
 162                 if (r->r_flags & RF_ALLOCATED) {
 163                         lwkt_reltoken(&ilock);
 164                         return EBUSY;
 165                 }
 166         }
 167
 168         /*
 169          * There really should only be one of these if we are in this
 170          * state and the code is working properly, but it can't hurt.
 171          */
 172         while (!CIRCLEQ_EMPTY(&rm->rm_list)) {
 173                 r = CIRCLEQ_FIRST(&rm->rm_list);
 174                 CIRCLEQ_REMOVE(&rm->rm_list, r, r_link);
 175                 kfree(r, M_RMAN);
 176         }
 177         lwkt_reltoken(&ilock);
 178         /* XXX what's the point of this if we are going to free the struct? */
 179         lwkt_gettoken(&ilock, &rman_tok);
 180         TAILQ_REMOVE(&rman_head, rm, rm_link);
 181         lwkt_reltoken(&ilock);
 182         kfree(rm->rm_slock, M_RMAN);
 183
 184         return 0;
 185 }
 186
 187 struct resource *
 188 rman_reserve_resource(struct rman *rm, u_long start, u_long end, u_long count,
 189                       u_int flags, struct device *dev)
 190 {
 191         u_int   want_activate;
 192         struct  resource *r, *s, *rv;
 193         u_long  rstart, rend;
 194         lwkt_tokref ilock;
 195
 196         rv = 0;
 197
 198         DPRINTF(("rman_reserve_resource: <%s> request: [%#lx, %#lx], length "
 199                "%#lx, flags %u, device %s\n", rm->rm_descr, start, end,
 200                count, flags,
 201                dev == NULL ? "<null>" : device_get_nameunit(dev)));
 202         want_activate = (flags & RF_ACTIVE);
 203         flags &= ~RF_ACTIVE;
 204
 205         lwkt_gettoken(&ilock, rm->rm_slock);
 206
 207         for (r = CIRCLEQ_FIRST(&rm->rm_list);
 208              !CIRCLEQ_TERMCOND(r, rm->rm_list) && r->r_end < start;
 209              r = CIRCLEQ_NEXT(r, r_link))
 210                 ;
 211
 212         if (CIRCLEQ_TERMCOND(r, rm->rm_list)) {
 213                 DPRINTF(("could not find a region\n"));
 214                 goto out;
 215         }
 216
 217         /*
 218          * First try to find an acceptable totally-unshared region.
 219          */
 220         for (s = r; !CIRCLEQ_TERMCOND(s, rm->rm_list);
 221              s = CIRCLEQ_NEXT(s, r_link)) {
 222                 DPRINTF(("considering [%#lx, %#lx]\n", s->r_start, s->r_end));
 223                 if (s->r_start > end) {
 224                         DPRINTF(("s->r_start (%#lx) > end (%#lx)\n",
 225                             s->r_start, end));
 226                         break;
 227                 }
 228                 if (s->r_flags & RF_ALLOCATED) {
 229                         DPRINTF(("region is allocated\n"));
 230                         continue;
 231                 }
 232                 rstart = max(s->r_start, start);
 233                 rstart = (rstart + ((1ul << RF_ALIGNMENT(flags))) - 1) &
 234                     ~((1ul << RF_ALIGNMENT(flags)) - 1);
 235                 rend = min(s->r_end, max(start + count, end));
 236                 DPRINTF(("truncated region: [%#lx, %#lx]; size %#lx (requested %#lx)\n",
 237                        rstart, rend, (rend - rstart + 1), count));
 238
 239                 if ((rend - rstart + 1) >= count) {
 240                         DPRINTF(("candidate region: [%#lx, %#lx], size %#lx\n",
 241                                rstart, rend, (rend - rstart + 1)));
 242                         if ((s->r_end - s->r_start + 1) == count) {
 243                                 DPRINTF(("candidate region is entire chunk\n"));
 244                                 rv = s;
 245                                 rv->r_flags |= RF_ALLOCATED | flags;
 246                                 rv->r_dev = dev;
 247                                 goto out;
 248                         }
 249
 250                         /*
 251                          * If s->r_start < rstart and
 252                          *    s->r_end > rstart + count - 1, then
 253                          * we need to split the region into three pieces
 254                          * (the middle one will get returned to the user).
 255                          * Otherwise, we are allocating at either the
 256                          * beginning or the end of s, so we only need to
 257                          * split it in two.  The first case requires
 258                          * two new allocations; the second requires but one.
 259                          */
 260                         rv = kmalloc(sizeof *rv, M_RMAN, M_NOWAIT);
 261                         if (rv == 0)
 262                                 goto out;
 263                         bzero(rv, sizeof *rv);
 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, M_NOWAIT);
 281                                 if (r == 0) {
 282                                         kfree(rv, M_RMAN);
 283                                         rv = 0;
 284                                         goto out;
 285                                 }
 286                                 bzero(r, sizeof *r);
 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);
 342                         if (rv == 0)
 343                                 goto out;
 344                         bzero(rv, sizeof *rv);
 345                         rv->r_start = s->r_start;
 346                         rv->r_end = s->r_end;
 347                         rv->r_flags = s->r_flags &
 348                                 (RF_ALLOCATED | RF_SHAREABLE | RF_TIMESHARE);
 349                         rv->r_dev = dev;
 350                         rv->r_rm = rm;
 351                         if (s->r_sharehead == 0) {
 352                                 s->r_sharehead = kmalloc(sizeof *s->r_sharehead,
 353                                                         M_RMAN, M_NOWAIT);
 354                                 if (s->r_sharehead == 0) {
 355                                         kfree(rv, M_RMAN);
 356                                         rv = 0;
 357                                         goto out;
 358                                 }
 359                                 bzero(s->r_sharehead, sizeof *s->r_sharehead);
 360                                 LIST_INIT(s->r_sharehead);
 361                                 LIST_INSERT_HEAD(s->r_sharehead, s,
 362                                                  r_sharelink);
 363                                 s->r_flags |= RF_FIRSTSHARE;
 364                         }
 365                         rv->r_sharehead = s->r_sharehead;
 366                         LIST_INSERT_HEAD(s->r_sharehead, rv, r_sharelink);
 367                         goto out;
 368                 }
 369         }
 370
 371         /*
 372          * We couldn't find anything.
 373          */
 374 out:
 375         /*
 376          * If the user specified RF_ACTIVE in the initial flags,
 377          * which is reflected in `want_activate', we attempt to atomically
 378          * activate the resource.  If this fails, we release the resource
 379          * and indicate overall failure.  (This behavior probably doesn't
 380          * make sense for RF_TIMESHARE-type resources.)
 381          */
 382         if (rv && want_activate) {
 383                 struct resource *whohas;
 384                 if (int_rman_activate_resource(rm, rv, &whohas)) {
 385                         int_rman_release_resource(rm, rv);
 386                         rv = 0;
 387                 }
 388         }
 389         lwkt_reltoken(&ilock);
 390         return (rv);
 391 }
 392
 393 static int
 394 int_rman_activate_resource(struct rman *rm, struct resource *r,
 395                            struct resource **whohas)
 396 {
 397         struct resource *s;
 398         int ok;
 399
 400         /*
 401          * If we are not timesharing, then there is nothing much to do.
 402          * If we already have the resource, then there is nothing at all to do.
 403          * If we are not on a sharing list with anybody else, then there is
 404          * little to do.
 405          */
 406         if ((r->r_flags & RF_TIMESHARE) == 0
 407             || (r->r_flags & RF_ACTIVE) != 0
 408             || r->r_sharehead == 0) {
 409                 r->r_flags |= RF_ACTIVE;
 410                 return 0;
 411         }
 412
 413         ok = 1;
 414         for (s = LIST_FIRST(r->r_sharehead); s && ok;
 415              s = LIST_NEXT(s, r_sharelink)) {
 416                 if ((s->r_flags & RF_ACTIVE) != 0) {
 417                         ok = 0;
 418                         *whohas = s;
 419                 }
 420         }
 421         if (ok) {
 422                 r->r_flags |= RF_ACTIVE;
 423                 return 0;
 424         }
 425         return EBUSY;
 426 }
 427
 428 int
 429 rman_activate_resource(struct resource *r)
 430 {
 431         int rv;
 432         struct resource *whohas;
 433         lwkt_tokref ilock;
 434         struct rman *rm;
 435
 436         rm = r->r_rm;
 437         lwkt_gettoken(&ilock, rm->rm_slock);
 438         rv = int_rman_activate_resource(rm, r, &whohas);
 439         lwkt_reltoken(&ilock);
 440         return rv;
 441 }
 442
 443 #if 0
 444
 445 /* XXX */
 446 int
 447 rman_await_resource(struct resource *r, lwkt_tokref_t ilock, int slpflags, int timo)
 448 {
 449         int     rv;
 450         struct  resource *whohas;
 451         struct  rman *rm;
 452
 453         rm = r->r_rm;
 454         for (;;) {
 455                 lwkt_gettoken(ilock, rm->rm_slock);
 456                 rv = int_rman_activate_resource(rm, r, &whohas);
 457                 if (rv != EBUSY)
 458                         return (rv);    /* returns with ilock held */
 459
 460                 if (r->r_sharehead == 0)
 461                         panic("rman_await_resource");
 462                 /*
 463                  * A critical section will hopefully will prevent a race
 464                  * between lwkt_reltoken and tsleep where a process
 465                  * could conceivably get in and release the resource
 466                  * before we have a chance to sleep on it. YYY
 467                  */
 468                 crit_enter();
 469                 whohas->r_flags |= RF_WANTED;
 470                 rv = tsleep(r->r_sharehead, slpflags, "rmwait", timo);
 471                 if (rv) {
 472                         lwkt_reltoken(ilock);
 473                         crit_exit();
 474                         return rv;
 475                 }
 476                 crit_exit();
 477         }
 478 }
 479
 480 #endif
 481
 482 static int
 483 int_rman_deactivate_resource(struct resource *r)
 484 {
 485         struct  rman *rm;
 486
 487         rm = r->r_rm;
 488         r->r_flags &= ~RF_ACTIVE;
 489         if (r->r_flags & RF_WANTED) {
 490                 r->r_flags &= ~RF_WANTED;
 491                 wakeup(r->r_sharehead);
 492         }
 493         return 0;
 494 }
 495
 496 int
 497 rman_deactivate_resource(struct resource *r)
 498 {
 499         lwkt_tokref ilock;
 500         struct rman *rm;
 501
 502         rm = r->r_rm;
 503         lwkt_gettoken(&ilock, rm->rm_slock);
 504         int_rman_deactivate_resource(r);
 505         lwkt_reltoken(&ilock);
 506         return 0;
 507 }
 508
 509 static int
 510 int_rman_release_resource(struct rman *rm, struct resource *r)
 511 {
 512         struct  resource *s, *t;
 513
 514         if (r->r_flags & RF_ACTIVE)
 515                 int_rman_deactivate_resource(r);
 516
 517         /*
 518          * Check for a sharing list first.  If there is one, then we don't
 519          * have to think as hard.
 520          */
 521         if (r->r_sharehead) {
 522                 /*
 523                  * If a sharing list exists, then we know there are at
 524                  * least two sharers.
 525                  *
 526                  * If we are in the main circleq, appoint someone else.
 527                  */
 528                 LIST_REMOVE(r, r_sharelink);
 529                 s = LIST_FIRST(r->r_sharehead);
 530                 if (r->r_flags & RF_FIRSTSHARE) {
 531                         s->r_flags |= RF_FIRSTSHARE;
 532                         CIRCLEQ_INSERT_BEFORE(&rm->rm_list, r, s, r_link);
 533                         CIRCLEQ_REMOVE(&rm->rm_list, r, r_link);
 534                 }
 535
 536                 /*
 537                  * Make sure that the sharing list goes away completely
 538                  * if the resource is no longer being shared at all.
 539                  */
 540                 if (LIST_NEXT(s, r_sharelink) == 0) {
 541                         kfree(s->r_sharehead, M_RMAN);
 542                         s->r_sharehead = 0;
 543                         s->r_flags &= ~RF_FIRSTSHARE;
 544                 }
 545                 goto out;
 546         }
 547
 548         /*
 549          * Look at the adjacent resources in the list and see if our
 550          * segment can be merged with any of them.
 551          */
 552         s = CIRCLEQ_PREV(r, r_link);
 553         t = CIRCLEQ_NEXT(r, r_link);
 554
 555         if (s != (void *)&rm->rm_list && (s->r_flags & RF_ALLOCATED) == 0
 556             && t != (void *)&rm->rm_list && (t->r_flags & RF_ALLOCATED) == 0) {
 557                 /*
 558                  * Merge all three segments.
 559                  */
 560                 s->r_end = t->r_end;
 561                 CIRCLEQ_REMOVE(&rm->rm_list, r, r_link);
 562                 CIRCLEQ_REMOVE(&rm->rm_list, t, r_link);
 563                 kfree(t, M_RMAN);
 564         } else if (s != (void *)&rm->rm_list
 565                    && (s->r_flags & RF_ALLOCATED) == 0) {
 566                 /*
 567                  * Merge previous segment with ours.
 568                  */
 569                 s->r_end = r->r_end;
 570                 CIRCLEQ_REMOVE(&rm->rm_list, r, r_link);
 571         } else if (t != (void *)&rm->rm_list
 572                    && (t->r_flags & RF_ALLOCATED) == 0) {
 573                 /*
 574                  * Merge next segment with ours.
 575                  */
 576                 t->r_start = r->r_start;
 577                 CIRCLEQ_REMOVE(&rm->rm_list, r, r_link);
 578         } else {
 579                 /*
 580                  * At this point, we know there is nothing we
 581                  * can potentially merge with, because on each
 582                  * side, there is either nothing there or what is
 583                  * there is still allocated.  In that case, we don't
 584                  * want to remove r from the list; we simply want to
 585                  * change it to an unallocated region and return
 586                  * without freeing anything.
 587                  */
 588                 r->r_flags &= ~RF_ALLOCATED;
 589                 return 0;
 590         }
 591
 592 out:
 593         kfree(r, M_RMAN);
 594         return 0;
 595 }
 596
 597 int
 598 rman_release_resource(struct resource *r)
 599 {
 600         struct  rman *rm = r->r_rm;
 601         lwkt_tokref ilock;
 602         int     rv;
 603
 604         lwkt_gettoken(&ilock, rm->rm_slock);
 605         rv = int_rman_release_resource(rm, r);
 606         lwkt_reltoken(&ilock);
 607         return (rv);
 608 }
 609
 610 uint32_t
 611 rman_make_alignment_flags(uint32_t size)
 612 {
 613         int     i;
 614
 615         /*
 616          * Find the hightest bit set, and add one if more than one bit
 617          * set.  We're effectively computing the ceil(log2(size)) here.
 618          */
 619         for (i = 32; i > 0; i--)
 620                 if ((1 << i) & size)
 621                         break;
 622         if (~(1 << i) & size)
 623                 i++;
 624
 625         return(RF_ALIGNMENT_LOG2(i));
 626 }