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  */
  31
  32 /*
  33  * The kernel resource manager.  This code is responsible for keeping track
  34  * of hardware resources which are apportioned out to various drivers.
  35  * It does not actually assign those resources, and it is not expected
  36  * that end-device drivers will call into this code directly.  Rather,
  37  * the code which implements the buses that those devices are attached to,
  38  * and the code which manages CPU resources, will call this code, and the
  39  * end-device drivers will make upcalls to that code to actually perform
  40  * the allocation.
  41  *
  42  * There are two sorts of resources managed by this code.  The first is
  43  * the more familiar array (RMAN_ARRAY) type; resources in this class
  44  * consist of a sequence of individually-allocatable objects which have
  45  * been numbered in some well-defined order.  Most of the resources
  46  * are of this type, as it is the most familiar.  The second type is
  47  * called a gauge (RMAN_GAUGE), and models fungible resources (i.e.,
  48  * resources in which each instance is indistinguishable from every
  49  * other instance).  The principal anticipated application of gauges
  50  * is in the context of power consumption, where a bus may have a specific
  51  * power budget which all attached devices share.  RMAN_GAUGE is not
  52  * implemented yet.
  53  *
  54  * For array resources, we make one simplifying assumption: two clients
  55  * sharing the same resource must use the same range of indices.  That
  56  * is to say, sharing of overlapping-but-not-identical regions is not
  57  * permitted.
  58  */
  59
  60 #include <sys/param.h>
  61 #include <sys/systm.h>
  62 #include <sys/kernel.h>
  63 #include <sys/lock.h>
  64 #include <sys/malloc.h>
  65 #include <sys/bus.h>            /* XXX debugging */
  66 #include <machine/bus.h>
  67 #include <sys/rman.h>
  68
  69 static MALLOC_DEFINE(M_RMAN, "rman", "Resource manager");
  70
  71 struct  rman_head rman_head;
  72 #ifndef NULL_SIMPLELOCKS
  73 static  struct simplelock rman_lock; /* mutex to protect rman_head */
  74 #endif
  75 static  int int_rman_activate_resource(struct rman *rm, struct resource *r,
  76                                        struct resource **whohas);
  77 static  int int_rman_deactivate_resource(struct resource *r);
  78 static  int int_rman_release_resource(struct rman *rm, struct resource *r);
  79
  80 #define CIRCLEQ_TERMCOND(var, head)     (var == (void *)&(head))
  81
  82 int
  83 rman_init(struct rman *rm)
  84 {
  85         static int once;
  86
  87         if (once == 0) {
  88                 once = 1;
  89                 TAILQ_INIT(&rman_head);
  90                 simple_lock_init(&rman_lock);
  91         }
  92
  93         if (rm->rm_type == RMAN_UNINIT)
  94                 panic("rman_init");
  95         if (rm->rm_type == RMAN_GAUGE)
  96                 panic("implement RMAN_GAUGE");
  97
  98         CIRCLEQ_INIT(&rm->rm_list);
  99         rm->rm_slock = malloc(sizeof *rm->rm_slock, M_RMAN, M_NOWAIT);
 100         if (rm->rm_slock == 0)
 101                 return ENOMEM;
 102         simple_lock_init(rm->rm_slock);
 103
 104         simple_lock(&rman_lock);
 105         TAILQ_INSERT_TAIL(&rman_head, rm, rm_link);
 106         simple_unlock(&rman_lock);
 107         return 0;
 108 }
 109
 110 /*
 111  * NB: this interface is not robust against programming errors which
 112  * add multiple copies of the same region.
 113  */
 114 int
 115 rman_manage_region(struct rman *rm, u_long start, u_long end)
 116 {
 117         struct resource *r, *s;
 118
 119         r = malloc(sizeof *r, M_RMAN, M_NOWAIT);
 120         if (r == 0)
 121                 return ENOMEM;
 122         bzero(r, sizeof *r);
 123         r->r_sharehead = 0;
 124         r->r_start = start;
 125         r->r_end = end;
 126         r->r_flags = 0;
 127         r->r_dev = 0;
 128         r->r_rm = rm;
 129
 130         simple_lock(rm->rm_slock);
 131         for (s = CIRCLEQ_FIRST(&rm->rm_list);
 132              !CIRCLEQ_TERMCOND(s, rm->rm_list) && s->r_end < r->r_start;
 133              s = CIRCLEQ_NEXT(s, r_link))
 134                 ;
 135
 136         if (CIRCLEQ_TERMCOND(s, rm->rm_list)) {
 137                 CIRCLEQ_INSERT_TAIL(&rm->rm_list, r, r_link);
 138         } else {
 139                 CIRCLEQ_INSERT_BEFORE(&rm->rm_list, s, r, r_link);
 140         }
 141
 142         simple_unlock(rm->rm_slock);
 143         return 0;
 144 }
 145
 146 int
 147 rman_fini(struct rman *rm)
 148 {
 149         struct resource *r;
 150
 151         simple_lock(rm->rm_slock);
 152         CIRCLEQ_FOREACH(r, &rm->rm_list, r_link) {
 153                 if (r->r_flags & RF_ALLOCATED) {
 154                         simple_unlock(rm->rm_slock);
 155                         return EBUSY;
 156                 }
 157         }
 158
 159         /*
 160          * There really should only be one of these if we are in this
 161          * state and the code is working properly, but it can't hurt.
 162          */
 163         while (!CIRCLEQ_EMPTY(&rm->rm_list)) {
 164                 r = CIRCLEQ_FIRST(&rm->rm_list);
 165                 CIRCLEQ_REMOVE(&rm->rm_list, r, r_link);
 166                 free(r, M_RMAN);
 167         }
 168         simple_unlock(rm->rm_slock);
 169         simple_lock(&rman_lock);
 170         TAILQ_REMOVE(&rman_head, rm, rm_link);
 171         simple_unlock(&rman_lock);
 172         free(rm->rm_slock, M_RMAN);
 173
 174         return 0;
 175 }
 176
 177 struct resource *
 178 rman_reserve_resource(struct rman *rm, u_long start, u_long end, u_long count,
 179                       u_int flags, struct device *dev)
 180 {
 181         u_int   want_activate;
 182         struct  resource *r, *s, *rv;
 183         u_long  rstart, rend;
 184
 185         rv = 0;
 186
 187 #ifdef RMAN_DEBUG
 188         printf("rman_reserve_resource: <%s> request: [%#lx, %#lx], length "
 189                "%#lx, flags %u, device %s%d\n", rm->rm_descr, start, end,
 190                count, flags, device_get_name(dev), device_get_unit(dev));
 191 #endif /* RMAN_DEBUG */
 192         want_activate = (flags & RF_ACTIVE);
 193         flags &= ~RF_ACTIVE;
 194
 195         simple_lock(rm->rm_slock);
 196
 197         for (r = CIRCLEQ_FIRST(&rm->rm_list);
 198              !CIRCLEQ_TERMCOND(r, rm->rm_list) && r->r_end < start;
 199              r = CIRCLEQ_NEXT(r, r_link))
 200                 ;
 201
 202         if (CIRCLEQ_TERMCOND(r, rm->rm_list)) {
 203 #ifdef RMAN_DEBUG
 204                 printf("could not find a region\n");
 205 #endif RMAN_DEBUG
 206                 goto out;
 207         }
 208
 209         /*
 210          * First try to find an acceptable totally-unshared region.
 211          */
 212         for (s = r; !CIRCLEQ_TERMCOND(s, rm->rm_list);
 213              s = CIRCLEQ_NEXT(s, r_link)) {
 214 #ifdef RMAN_DEBUG
 215                 printf("considering [%#lx, %#lx]\n", s->r_start, s->r_end);
 216 #endif /* RMAN_DEBUG */
 217                 if (s->r_start > end) {
 218 #ifdef RMAN_DEBUG
 219                         printf("s->r_start (%#lx) > end (%#lx)\n", s->r_start, end);
 220 #endif /* RMAN_DEBUG */
 221                         break;
 222                 }
 223                 if (s->r_flags & RF_ALLOCATED) {
 224 #ifdef RMAN_DEBUG
 225                         printf("region is allocated\n");
 226 #endif /* RMAN_DEBUG */
 227                         continue;
 228                 }
 229                 rstart = max(s->r_start, start);
 230                 rstart = (rstart + ((1ul << RF_ALIGNMENT(flags))) - 1) &
 231                     ~((1ul << RF_ALIGNMENT(flags)) - 1);
 232                 rend = min(s->r_end, max(start + count, end));
 233 #ifdef RMAN_DEBUG
 234                 printf("truncated region: [%#lx, %#lx]; size %#lx (requested %#lx)\n",
 235                        rstart, rend, (rend - rstart + 1), count);
 236 #endif /* RMAN_DEBUG */
 237
 238                 if ((rend - rstart + 1) >= count) {
 239 #ifdef RMAN_DEBUG
 240                         printf("candidate region: [%#lx, %#lx], size %#lx\n",
 241                                rend, rstart, (rend - rstart + 1));
 242 #endif /* RMAN_DEBUG */
 243                         if ((s->r_end - s->r_start + 1) == count) {
 244 #ifdef RMAN_DEBUG
 245                                 printf("candidate region is entire chunk\n");
 246 #endif /* RMAN_DEBUG */
 247                                 rv = s;
 248                                 rv->r_flags |= RF_ALLOCATED | flags;
 249                                 rv->r_dev = dev;
 250                                 goto out;
 251                         }
 252
 253                         /*
 254                          * If s->r_start < rstart and
 255                          *    s->r_end > rstart + count - 1, then
 256                          * we need to split the region into three pieces
 257                          * (the middle one will get returned to the user).
 258                          * Otherwise, we are allocating at either the
 259                          * beginning or the end of s, so we only need to
 260                          * split it in two.  The first case requires
 261                          * two new allocations; the second requires but one.
 262                          */
 263                         rv = malloc(sizeof *rv, M_RMAN, M_NOWAIT);
 264                         if (rv == 0)
 265                                 goto out;
 266                         bzero(rv, sizeof *rv);
 267                         rv->r_start = rstart;
 268                         rv->r_end = rstart + count - 1;
 269                         rv->r_flags = flags | RF_ALLOCATED;
 270                         rv->r_dev = dev;
 271                         rv->r_sharehead = 0;
 272                         rv->r_rm = rm;
 273
 274                         if (s->r_start < rv->r_start && s->r_end > rv->r_end) {
 275 #ifdef RMAN_DEBUG
 276                                 printf("splitting region in three parts: "
 277                                        "[%#lx, %#lx]; [%#lx, %#lx]; [%#lx, %#lx]\n",
 278                                        s->r_start, rv->r_start - 1,
 279                                        rv->r_start, rv->r_end,
 280                                        rv->r_end + 1, s->r_end);
 281 #endif /* RMAN_DEBUG */
 282                                 /*
 283                                  * We are allocating in the middle.
 284                                  */
 285                                 r = malloc(sizeof *r, M_RMAN, M_NOWAIT);
 286                                 if (r == 0) {
 287                                         free(rv, M_RMAN);
 288                                         rv = 0;
 289                                         goto out;
 290                                 }
 291                                 bzero(r, sizeof *r);
 292                                 r->r_start = rv->r_end + 1;
 293                                 r->r_end = s->r_end;
 294                                 r->r_flags = s->r_flags;
 295                                 r->r_dev = 0;
 296                                 r->r_sharehead = 0;
 297                                 r->r_rm = rm;
 298                                 s->r_end = rv->r_start - 1;
 299                                 CIRCLEQ_INSERT_AFTER(&rm->rm_list, s, rv,
 300                                                      r_link);
 301                                 CIRCLEQ_INSERT_AFTER(&rm->rm_list, rv, r,
 302                                                      r_link);
 303                         } else if (s->r_start == rv->r_start) {
 304 #ifdef RMAN_DEBUG
 305                                 printf("allocating from the beginning\n");
 306 #endif /* RMAN_DEBUG */
 307                                 /*
 308                                  * We are allocating at the beginning.
 309                                  */
 310                                 s->r_start = rv->r_end + 1;
 311                                 CIRCLEQ_INSERT_BEFORE(&rm->rm_list, s, rv,
 312                                                       r_link);
 313                         } else {
 314 #ifdef RMAN_DEBUG
 315                                 printf("allocating at the end\n");
 316 #endif /* RMAN_DEBUG */
 317                                 /*
 318                                  * We are allocating at the end.
 319                                  */
 320                                 s->r_end = rv->r_start - 1;
 321                                 CIRCLEQ_INSERT_AFTER(&rm->rm_list, s, rv,
 322                                                      r_link);
 323                         }
 324                         goto out;
 325                 }
 326         }
 327
 328         /*
 329          * Now find an acceptable shared region, if the client's requirements
 330          * allow sharing.  By our implementation restriction, a candidate
 331          * region must match exactly by both size and sharing type in order
 332          * to be considered compatible with the client's request.  (The
 333          * former restriction could probably be lifted without too much
 334          * additional work, but this does not seem warranted.)
 335          */
 336 #ifdef RMAN_DEBUG
 337         printf("no unshared regions found\n");
 338 #endif /* RMAN_DEBUG */
 339         if ((flags & (RF_SHAREABLE | RF_TIMESHARE)) == 0)
 340                 goto out;
 341
 342         for (s = r; !CIRCLEQ_TERMCOND(s, rm->rm_list);
 343              s = CIRCLEQ_NEXT(s, r_link)) {
 344                 if (s->r_start > end)
 345                         break;
 346                 if ((s->r_flags & flags) != flags)
 347                         continue;
 348                 rstart = max(s->r_start, start);
 349                 rend = min(s->r_end, max(start + count, end));
 350                 if (s->r_start >= start && s->r_end <= end
 351                     && (s->r_end - s->r_start + 1) == count) {
 352                         rv = malloc(sizeof *rv, M_RMAN, M_NOWAIT);
 353                         if (rv == 0)
 354                                 goto out;
 355                         bzero(rv, sizeof *rv);
 356                         rv->r_start = s->r_start;
 357                         rv->r_end = s->r_end;
 358                         rv->r_flags = s->r_flags &
 359                                 (RF_ALLOCATED | RF_SHAREABLE | RF_TIMESHARE);
 360                         rv->r_dev = dev;
 361                         rv->r_rm = rm;
 362                         if (s->r_sharehead == 0) {
 363                                 s->r_sharehead = malloc(sizeof *s->r_sharehead,
 364                                                         M_RMAN, M_NOWAIT);
 365                                 if (s->r_sharehead == 0) {
 366                                         free(rv, M_RMAN);
 367                                         rv = 0;
 368                                         goto out;
 369                                 }
 370                                 bzero(s->r_sharehead, sizeof *s->r_sharehead);
 371                                 LIST_INIT(s->r_sharehead);
 372                                 LIST_INSERT_HEAD(s->r_sharehead, s,
 373                                                  r_sharelink);
 374                                 s->r_flags |= RF_FIRSTSHARE;
 375                         }
 376                         rv->r_sharehead = s->r_sharehead;
 377                         LIST_INSERT_HEAD(s->r_sharehead, rv, r_sharelink);
 378                         goto out;
 379                 }
 380         }
 381
 382         /*
 383          * We couldn't find anything.
 384          */
 385 out:
 386         /*
 387          * If the user specified RF_ACTIVE in the initial flags,
 388          * which is reflected in `want_activate', we attempt to atomically
 389          * activate the resource.  If this fails, we release the resource
 390          * and indicate overall failure.  (This behavior probably doesn't
 391          * make sense for RF_TIMESHARE-type resources.)
 392          */
 393         if (rv && want_activate) {
 394                 struct resource *whohas;
 395                 if (int_rman_activate_resource(rm, rv, &whohas)) {
 396                         int_rman_release_resource(rm, rv);
 397                         rv = 0;
 398                 }
 399         }
 400
 401         simple_unlock(rm->rm_slock);
 402         return (rv);
 403 }
 404
 405 static int
 406 int_rman_activate_resource(struct rman *rm, struct resource *r,
 407                            struct resource **whohas)
 408 {
 409         struct resource *s;
 410         int ok;
 411
 412         /*
 413          * If we are not timesharing, then there is nothing much to do.
 414          * If we already have the resource, then there is nothing at all to do.
 415          * If we are not on a sharing list with anybody else, then there is
 416          * little to do.
 417          */
 418         if ((r->r_flags & RF_TIMESHARE) == 0
 419             || (r->r_flags & RF_ACTIVE) != 0
 420             || r->r_sharehead == 0) {
 421                 r->r_flags |= RF_ACTIVE;
 422                 return 0;
 423         }
 424
 425         ok = 1;
 426         for (s = LIST_FIRST(r->r_sharehead); s && ok;
 427              s = LIST_NEXT(s, r_sharelink)) {
 428                 if ((s->r_flags & RF_ACTIVE) != 0) {
 429                         ok = 0;
 430                         *whohas = s;
 431                 }
 432         }
 433         if (ok) {
 434                 r->r_flags |= RF_ACTIVE;
 435                 return 0;
 436         }
 437         return EBUSY;
 438 }
 439
 440 int
 441 rman_activate_resource(struct resource *r)
 442 {
 443         int rv;
 444         struct resource *whohas;
 445         struct rman *rm;
 446
 447         rm = r->r_rm;
 448         simple_lock(rm->rm_slock);
 449         rv = int_rman_activate_resource(rm, r, &whohas);
 450         simple_unlock(rm->rm_slock);
 451         return rv;
 452 }
 453
 454 int
 455 rman_await_resource(struct resource *r, int pri, int timo)
 456 {
 457         int     rv, s;
 458         struct  resource *whohas;
 459         struct  rman *rm;
 460
 461         rm = r->r_rm;
 462         for (;;) {
 463                 simple_lock(rm->rm_slock);
 464                 rv = int_rman_activate_resource(rm, r, &whohas);
 465                 if (rv != EBUSY)
 466                         return (rv);    /* returns with simplelock */
 467
 468                 if (r->r_sharehead == 0)
 469                         panic("rman_await_resource");
 470                 /*
 471                  * splhigh hopefully will prevent a race between
 472                  * simple_unlock and tsleep where a process
 473                  * could conceivably get in and release the resource
 474                  * before we have a chance to sleep on it.
 475                  */
 476                 s = splhigh();
 477                 whohas->r_flags |= RF_WANTED;
 478                 simple_unlock(rm->rm_slock);
 479                 rv = tsleep(r->r_sharehead, pri, "rmwait", timo);
 480                 if (rv) {
 481                         splx(s);
 482                         return rv;
 483                 }
 484                 simple_lock(rm->rm_slock);
 485                 splx(s);
 486         }
 487 }
 488
 489 static int
 490 int_rman_deactivate_resource(struct resource *r)
 491 {
 492         struct  rman *rm;
 493
 494         rm = r->r_rm;
 495         r->r_flags &= ~RF_ACTIVE;
 496         if (r->r_flags & RF_WANTED) {
 497                 r->r_flags &= ~RF_WANTED;
 498                 wakeup(r->r_sharehead);
 499         }
 500         return 0;
 501 }
 502
 503 int
 504 rman_deactivate_resource(struct resource *r)
 505 {
 506         struct  rman *rm;
 507
 508         rm = r->r_rm;
 509         simple_lock(rm->rm_slock);
 510         int_rman_deactivate_resource(r);
 511         simple_unlock(rm->rm_slock);
 512         return 0;
 513 }
 514
 515 static int
 516 int_rman_release_resource(struct rman *rm, struct resource *r)
 517 {
 518         struct  resource *s, *t;
 519
 520         if (r->r_flags & RF_ACTIVE)
 521                 int_rman_deactivate_resource(r);
 522
 523         /*
 524          * Check for a sharing list first.  If there is one, then we don't
 525          * have to think as hard.
 526          */
 527         if (r->r_sharehead) {
 528                 /*
 529                  * If a sharing list exists, then we know there are at
 530                  * least two sharers.
 531                  *
 532                  * If we are in the main circleq, appoint someone else.
 533                  */
 534                 LIST_REMOVE(r, r_sharelink);
 535                 s = LIST_FIRST(r->r_sharehead);
 536                 if (r->r_flags & RF_FIRSTSHARE) {
 537                         s->r_flags |= RF_FIRSTSHARE;
 538                         CIRCLEQ_INSERT_BEFORE(&rm->rm_list, r, s, r_link);
 539                         CIRCLEQ_REMOVE(&rm->rm_list, r, r_link);
 540                 }
 541
 542                 /*
 543                  * Make sure that the sharing list goes away completely
 544                  * if the resource is no longer being shared at all.
 545                  */
 546                 if (LIST_NEXT(s, r_sharelink) == 0) {
 547                         free(s->r_sharehead, M_RMAN);
 548                         s->r_sharehead = 0;
 549                         s->r_flags &= ~RF_FIRSTSHARE;
 550                 }
 551                 goto out;
 552         }
 553
 554         /*
 555          * Look at the adjacent resources in the list and see if our
 556          * segment can be merged with any of them.
 557          */
 558         s = CIRCLEQ_PREV(r, r_link);
 559         t = CIRCLEQ_NEXT(r, r_link);
 560
 561         if (s != (void *)&rm->rm_list && (s->r_flags & RF_ALLOCATED) == 0
 562             && t != (void *)&rm->rm_list && (t->r_flags & RF_ALLOCATED) == 0) {
 563                 /*
 564                  * Merge all three segments.
 565                  */
 566                 s->r_end = t->r_end;
 567                 CIRCLEQ_REMOVE(&rm->rm_list, r, r_link);
 568                 CIRCLEQ_REMOVE(&rm->rm_list, t, r_link);
 569                 free(t, M_RMAN);
 570         } else if (s != (void *)&rm->rm_list
 571                    && (s->r_flags & RF_ALLOCATED) == 0) {
 572                 /*
 573                  * Merge previous segment with ours.
 574                  */
 575                 s->r_end = r->r_end;
 576                 CIRCLEQ_REMOVE(&rm->rm_list, r, r_link);
 577         } else if (t != (void *)&rm->rm_list
 578                    && (t->r_flags & RF_ALLOCATED) == 0) {
 579                 /*
 580                  * Merge next segment with ours.
 581                  */
 582                 t->r_start = r->r_start;
 583                 CIRCLEQ_REMOVE(&rm->rm_list, r, r_link);
 584         } else {
 585                 /*
 586                  * At this point, we know there is nothing we
 587                  * can potentially merge with, because on each
 588                  * side, there is either nothing there or what is
 589                  * there is still allocated.  In that case, we don't
 590                  * want to remove r from the list; we simply want to
 591                  * change it to an unallocated region and return
 592                  * without freeing anything.
 593                  */
 594                 r->r_flags &= ~RF_ALLOCATED;
 595                 return 0;
 596         }
 597
 598 out:
 599         free(r, M_RMAN);
 600         return 0;
 601 }
 602
 603 int
 604 rman_release_resource(struct resource *r)
 605 {
 606         int     rv;
 607         struct  rman *rm = r->r_rm;
 608
 609         simple_lock(rm->rm_slock);
 610         rv = int_rman_release_resource(rm, r);
 611         simple_unlock(rm->rm_slock);
 612         return (rv);
 613 }
 614
 615 uint32_t
 616 rman_make_alignment_flags(uint32_t size)
 617 {
 618         int     i;
 619
 620         /*
 621          * Find the hightest bit set, and add one if more than one bit
 622          * set.  We're effectively computing the ceil(log2(size)) here.
 623          */
 624         for (i = 32; i > 0; i--)
 625                 if ((1 << i) & size)
 626                         break;
 627         if (~(1 << i) & size)
 628                 i++;
 629
 630         return(RF_ALIGNMENT_LOG2(i));
 631 }