kern_subr.c

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    1 /*
    2  * Copyright (c) 1982, 1986, 1991, 1993
    3  *      The Regents of the University of California.  All rights reserved.
    4  * (c) UNIX System Laboratories, Inc.
    5  * All or some portions of this file are derived from material licensed
    6  * to the University of California by American Telephone and Telegraph
    7  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
    8  * the permission of UNIX System Laboratories, Inc.
    9  *
   10  * Redistribution and use in source and binary forms, with or without
   11  * modification, are permitted provided that the following conditions
   12  * are met:
   13  * 1. Redistributions of source code must retain the above copyright
   14  *    notice, this list of conditions and the following disclaimer.
   15  * 2. Redistributions in binary form must reproduce the above copyright
   16  *    notice, this list of conditions and the following disclaimer in the
   17  *    documentation and/or other materials provided with the distribution.
   18  * 3. All advertising materials mentioning features or use of this software
   19  *    must display the following acknowledgement:
   20  *      This product includes software developed by the University of
   21  *      California, Berkeley and its contributors.
   22  * 4. Neither the name of the University nor the names of its contributors
   23  *    may be used to endorse or promote products derived from this software
   24  *    without specific prior written permission.
   25  *
   26  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   36  * SUCH DAMAGE.
   37  *
   38  *      @(#)kern_subr.c 8.3 (Berkeley) 1/21/94
   39  * $FreeBSD: releng/5.0/sys/kern/kern_subr.c 120697 2003-10-03 16:57:38Z nectar $
   40  */
   41 
   42 #include "opt_zero.h"
   43 
   44 #include <sys/param.h>
   45 #include <sys/systm.h>
   46 #include <sys/kernel.h>
   47 #include <sys/ktr.h>
   48 #include <sys/lock.h>
   49 #include <sys/mutex.h>
   50 #include <sys/proc.h>
   51 #include <sys/malloc.h>
   52 #include <sys/resourcevar.h>
   53 #include <sys/sched.h>
   54 #include <sys/sysctl.h>
   55 #include <sys/vnode.h>
   56 #include <machine/limits.h>
   57 
   58 #include <vm/vm.h>
   59 #include <vm/vm_page.h>
   60 #include <vm/vm_map.h>
   61 #ifdef ZERO_COPY_SOCKETS
   62 #include <vm/vm_param.h>
   63 #endif
   64 #if defined(ZERO_COPY_SOCKETS) || defined(ENABLE_VFS_IOOPT)
   65 #include <vm/vm_object.h>
   66 #endif
   67 
   68 SYSCTL_INT(_kern, KERN_IOV_MAX, iov_max, CTLFLAG_RD, NULL, UIO_MAXIOV, 
   69         "Maximum number of elements in an I/O vector; sysconf(_SC_IOV_MAX)");
   70 
   71 #if defined(ZERO_COPY_SOCKETS) || defined(ENABLE_VFS_IOOPT)
   72 static int userspaceco(caddr_t cp, u_int cnt, struct uio *uio,
   73                        struct vm_object *obj, int disposable);
   74 #endif
   75 
   76 #ifdef ZERO_COPY_SOCKETS
   77 /* Declared in uipc_socket.c */
   78 extern int so_zero_copy_receive;
   79 
   80 static int vm_pgmoveco(vm_map_t mapa, vm_object_t srcobj, vm_offset_t kaddr,
   81                        vm_offset_t uaddr);
   82 
   83 static int
   84 vm_pgmoveco(mapa, srcobj,  kaddr, uaddr)
   85         vm_map_t mapa;
   86         vm_object_t srcobj;
   87         vm_offset_t kaddr, uaddr;
   88 {
   89         vm_map_t map = mapa;
   90         vm_page_t kern_pg, user_pg;
   91         vm_object_t uobject;
   92         vm_map_entry_t entry;
   93         vm_pindex_t upindex, kpindex;
   94         vm_prot_t prot;
   95         boolean_t wired;
   96 
   97         /*
   98          * First lookup the kernel page.
   99          */
  100         kern_pg = PHYS_TO_VM_PAGE(vtophys(kaddr));
  101 
  102         if ((vm_map_lookup(&map, uaddr,
  103                            VM_PROT_READ, &entry, &uobject,
  104                            &upindex, &prot, &wired)) != KERN_SUCCESS) {
  105                 return(EFAULT);
  106         }
  107         if ((user_pg = vm_page_lookup(uobject, upindex)) != NULL) {
  108                 do
  109                         vm_page_lock_queues();
  110                 while (vm_page_sleep_if_busy(user_pg, 1, "vm_pgmoveco"));
  111                 vm_page_busy(user_pg);
  112                 pmap_remove_all(user_pg);
  113                 vm_page_free(user_pg);
  114                 vm_page_unlock_queues();
  115         }
  116 
  117         if (kern_pg->busy || ((kern_pg->queue - kern_pg->pc) == PQ_FREE) ||
  118             (kern_pg->hold_count != 0)|| (kern_pg->flags & PG_BUSY)) {
  119                 printf("vm_pgmoveco: pindex(%lu), busy(%d), PG_BUSY(%d), "
  120                        "hold(%d) paddr(0x%lx)\n", (u_long)kern_pg->pindex,
  121                         kern_pg->busy, (kern_pg->flags & PG_BUSY) ? 1 : 0,
  122                         kern_pg->hold_count, (u_long)kern_pg->phys_addr);
  123                 if ((kern_pg->queue - kern_pg->pc) == PQ_FREE)
  124                         panic("vm_pgmoveco: renaming free page");
  125                 else
  126                         panic("vm_pgmoveco: renaming busy page");
  127         }
  128         kpindex = kern_pg->pindex;
  129         vm_page_busy(kern_pg);
  130         vm_page_rename(kern_pg, uobject, upindex);
  131         vm_page_flag_clear(kern_pg, PG_BUSY);
  132         kern_pg->valid = VM_PAGE_BITS_ALL;
  133         
  134         vm_map_lookup_done(map, entry);
  135         return(KERN_SUCCESS);
  136 }
  137 #endif /* ZERO_COPY_SOCKETS */
  138 
  139 int
  140 uiomove(cp, n, uio)
  141         register caddr_t cp;
  142         register int n;
  143         register struct uio *uio;
  144 {
  145         struct thread *td = curthread;
  146         register struct iovec *iov;
  147         u_int cnt;
  148         int error = 0;
  149         int save = 0;
  150 
  151         KASSERT(uio->uio_rw == UIO_READ || uio->uio_rw == UIO_WRITE,
  152             ("uiomove: mode"));
  153         KASSERT(uio->uio_segflg != UIO_USERSPACE || uio->uio_td == curthread,
  154             ("uiomove proc"));
  155 
  156         if (td) {
  157                 mtx_lock_spin(&sched_lock);
  158                 save = td->td_flags & TDF_DEADLKTREAT;
  159                 td->td_flags |= TDF_DEADLKTREAT;
  160                 mtx_unlock_spin(&sched_lock);
  161         }
  162 
  163         while (n > 0 && uio->uio_resid) {
  164                 iov = uio->uio_iov;
  165                 cnt = iov->iov_len;
  166                 if (cnt == 0) {
  167                         uio->uio_iov++;
  168                         uio->uio_iovcnt--;
  169                         continue;
  170                 }
  171                 if (cnt > n)
  172                         cnt = n;
  173 
  174                 switch (uio->uio_segflg) {
  175 
  176                 case UIO_USERSPACE:
  177                         if (ticks - PCPU_GET(switchticks) >= hogticks)
  178                                 uio_yield();
  179                         if (uio->uio_rw == UIO_READ)
  180                                 error = copyout(cp, iov->iov_base, cnt);
  181                         else
  182                                 error = copyin(iov->iov_base, cp, cnt);
  183                         if (error)
  184                                 goto out;
  185                         break;
  186 
  187                 case UIO_SYSSPACE:
  188                         if (uio->uio_rw == UIO_READ)
  189                                 bcopy(cp, iov->iov_base, cnt);
  190                         else
  191                                 bcopy(iov->iov_base, cp, cnt);
  192                         break;
  193                 case UIO_NOCOPY:
  194                         break;
  195                 }
  196                 iov->iov_base = (char *)iov->iov_base + cnt;
  197                 iov->iov_len -= cnt;
  198                 uio->uio_resid -= cnt;
  199                 uio->uio_offset += cnt;
  200                 cp += cnt;
  201                 n -= cnt;
  202         }
  203 out:
  204         if (td != curthread) printf("uiomove: IT CHANGED!");
  205         td = curthread; /* Might things have changed in copyin/copyout? */
  206         if (td) {
  207                 mtx_lock_spin(&sched_lock);
  208                 td->td_flags = (td->td_flags & ~TDF_DEADLKTREAT) | save;
  209                 mtx_unlock_spin(&sched_lock);
  210         }
  211         return (error);
  212 }
  213 
  214 /*
  215  * Wrapper for uiomove() that validates the arguments against a known-good
  216  * kernel buffer.  Currently, uiomove accepts a signed (n) argument, which
  217  * is almost definitely a bad thing, so we catch that here as well.  We
  218  * return a runtime failure, but it might be desirable to generate a runtime
  219  * assertion failure instead.
  220  */
  221 int
  222 uiomove_frombuf(void *buf, int buflen, struct uio *uio)
  223 {
  224         unsigned int offset, n;
  225 
  226         if (uio->uio_offset < 0 || uio->uio_resid < 0 ||
  227             (offset = uio->uio_offset) != uio->uio_offset)
  228                 return (EINVAL);
  229         if (buflen <= 0 || offset >= buflen)
  230                 return (0);
  231         if ((n = buflen - offset) > INT_MAX)
  232                 return (EINVAL);
  233         return (uiomove((char *)buf + offset, n, uio));
  234 }
  235 
  236 #if defined(ENABLE_VFS_IOOPT) || defined(ZERO_COPY_SOCKETS)
  237 /*
  238  * Experimental support for zero-copy I/O
  239  */
  240 static int
  241 userspaceco(cp, cnt, uio, obj, disposable)
  242         caddr_t cp;
  243         u_int cnt;
  244         struct uio *uio;
  245         struct vm_object *obj;
  246         int disposable;
  247 {
  248         struct iovec *iov;
  249         int error;
  250 
  251         iov = uio->uio_iov;
  252 
  253 #ifdef ZERO_COPY_SOCKETS
  254 
  255         if (uio->uio_rw == UIO_READ) {
  256                 if ((so_zero_copy_receive != 0)
  257                  && (obj != NULL)
  258                  && ((cnt & PAGE_MASK) == 0)
  259                  && ((((intptr_t) iov->iov_base) & PAGE_MASK) == 0)
  260                  && ((uio->uio_offset & PAGE_MASK) == 0)
  261                  && ((((intptr_t) cp) & PAGE_MASK) == 0)
  262                  && (obj->type == OBJT_DEFAULT)
  263                  && (disposable != 0)) {
  264                         /* SOCKET: use page-trading */
  265                         /*
  266                          * We only want to call vm_pgmoveco() on
  267                          * disposeable pages, since it gives the
  268                          * kernel page to the userland process.
  269                          */
  270                         error = vm_pgmoveco(&curproc->p_vmspace->vm_map,
  271                                             obj, (vm_offset_t)cp, 
  272                                             (vm_offset_t)iov->iov_base);
  273 
  274                         /*
  275                          * If we get an error back, attempt
  276                          * to use copyout() instead.  The
  277                          * disposable page should be freed
  278                          * automatically if we weren't able to move
  279                          * it into userland.
  280                          */
  281                         if (error != 0)
  282                                 error = copyout(cp, iov->iov_base, cnt);
  283 #ifdef ENABLE_VFS_IOOPT
  284                 } else if ((vfs_ioopt != 0)
  285                  && ((cnt & PAGE_MASK) == 0)
  286                  && ((((intptr_t) iov->iov_base) & PAGE_MASK) == 0)
  287                  && ((uio->uio_offset & PAGE_MASK) == 0)
  288                  && ((((intptr_t) cp) & PAGE_MASK) == 0)) {
  289                         error = vm_uiomove(&curproc->p_vmspace->vm_map, obj,
  290                                            uio->uio_offset, cnt,
  291                                            (vm_offset_t) iov->iov_base, NULL);
  292 #endif /* ENABLE_VFS_IOOPT */
  293                 } else {
  294                         error = copyout(cp, iov->iov_base, cnt);
  295                 }
  296         } else {
  297                 error = copyin(iov->iov_base, cp, cnt);
  298         }
  299 #else /* ZERO_COPY_SOCKETS */
  300         if (uio->uio_rw == UIO_READ) {
  301 #ifdef ENABLE_VFS_IOOPT
  302                 if ((vfs_ioopt != 0)
  303                  && ((cnt & PAGE_MASK) == 0)
  304                  && ((((intptr_t) iov->iov_base) & PAGE_MASK) == 0)
  305                  && ((uio->uio_offset & PAGE_MASK) == 0)
  306                  && ((((intptr_t) cp) & PAGE_MASK) == 0)) {
  307                         error = vm_uiomove(&curproc->p_vmspace->vm_map, obj,
  308                                            uio->uio_offset, cnt,
  309                                            (vm_offset_t) iov->iov_base, NULL);
  310                 } else
  311 #endif /* ENABLE_VFS_IOOPT */
  312                 {
  313                         error = copyout(cp, iov->iov_base, cnt);
  314                 }
  315         } else {
  316                 error = copyin(iov->iov_base, cp, cnt);
  317         }
  318 #endif /* ZERO_COPY_SOCKETS */
  319 
  320         return (error);
  321 }
  322 
  323 int
  324 uiomoveco(cp, n, uio, obj, disposable)
  325         caddr_t cp;
  326         int n;
  327         struct uio *uio;
  328         struct vm_object *obj;
  329         int disposable;
  330 {
  331         struct iovec *iov;
  332         u_int cnt;
  333         int error;
  334 
  335         KASSERT(uio->uio_rw == UIO_READ || uio->uio_rw == UIO_WRITE,
  336             ("uiomoveco: mode"));
  337         KASSERT(uio->uio_segflg != UIO_USERSPACE || uio->uio_td == curthread,
  338             ("uiomoveco proc"));
  339 
  340         while (n > 0 && uio->uio_resid) {
  341                 iov = uio->uio_iov;
  342                 cnt = iov->iov_len;
  343                 if (cnt == 0) {
  344                         uio->uio_iov++;
  345                         uio->uio_iovcnt--;
  346                         continue;
  347                 }
  348                 if (cnt > n)
  349                         cnt = n;
  350 
  351                 switch (uio->uio_segflg) {
  352 
  353                 case UIO_USERSPACE:
  354                         if (ticks - PCPU_GET(switchticks) >= hogticks)
  355                                 uio_yield();
  356 
  357                         error = userspaceco(cp, cnt, uio, obj, disposable);
  358 
  359                         if (error)
  360                                 return (error);
  361                         break;
  362 
  363                 case UIO_SYSSPACE:
  364                         if (uio->uio_rw == UIO_READ)
  365                                 bcopy(cp, iov->iov_base, cnt);
  366                         else
  367                                 bcopy(iov->iov_base, cp, cnt);
  368                         break;
  369                 case UIO_NOCOPY:
  370                         break;
  371                 }
  372                 iov->iov_base = (char *)iov->iov_base + cnt;
  373                 iov->iov_len -= cnt;
  374                 uio->uio_resid -= cnt;
  375                 uio->uio_offset += cnt;
  376                 cp += cnt;
  377                 n -= cnt;
  378         }
  379         return (0);
  380 }
  381 #endif /* ENABLE_VFS_IOOPT || ZERO_COPY_SOCKETS */
  382 
  383 #ifdef ENABLE_VFS_IOOPT
  384 
  385 /*
  386  * Experimental support for zero-copy I/O
  387  */
  388 int
  389 uioread(n, uio, obj, nread)
  390         int n;
  391         struct uio *uio;
  392         struct vm_object *obj;
  393         int *nread;
  394 {
  395         int npagesmoved;
  396         struct iovec *iov;
  397         u_int cnt, tcnt;
  398         int error;
  399 
  400         *nread = 0;
  401         if (vfs_ioopt < 2)
  402                 return 0;
  403 
  404         error = 0;
  405 
  406         while (n > 0 && uio->uio_resid) {
  407                 iov = uio->uio_iov;
  408                 cnt = iov->iov_len;
  409                 if (cnt == 0) {
  410                         uio->uio_iov++;
  411                         uio->uio_iovcnt--;
  412                         continue;
  413                 }
  414                 if (cnt > n)
  415                         cnt = n;
  416 
  417                 if ((uio->uio_segflg == UIO_USERSPACE) &&
  418                         ((((intptr_t) iov->iov_base) & PAGE_MASK) == 0) &&
  419                                  ((uio->uio_offset & PAGE_MASK) == 0) ) {
  420 
  421                         if (cnt < PAGE_SIZE)
  422                                 break;
  423 
  424                         cnt &= ~PAGE_MASK;
  425 
  426                         if (ticks - PCPU_GET(switchticks) >= hogticks)
  427                                 uio_yield();
  428                         error = vm_uiomove(&curproc->p_vmspace->vm_map, obj,
  429                                                 uio->uio_offset, cnt,
  430                                                 (vm_offset_t) iov->iov_base, &npagesmoved);
  431 
  432                         if (npagesmoved == 0)
  433                                 break;
  434 
  435                         tcnt = npagesmoved * PAGE_SIZE;
  436                         cnt = tcnt;
  437 
  438                         if (error)
  439                                 break;
  440 
  441                         iov->iov_base = (char *)iov->iov_base + cnt;
  442                         iov->iov_len -= cnt;
  443                         uio->uio_resid -= cnt;
  444                         uio->uio_offset += cnt;
  445                         *nread += cnt;
  446                         n -= cnt;
  447                 } else {
  448                         break;
  449                 }
  450         }
  451         return error;
  452 }
  453 #endif /* ENABLE_VFS_IOOPT */
  454 
  455 /*
  456  * Give next character to user as result of read.
  457  */
  458 int
  459 ureadc(c, uio)
  460         register int c;
  461         register struct uio *uio;
  462 {
  463         register struct iovec *iov;
  464         register char *iov_base;
  465 
  466 again:
  467         if (uio->uio_iovcnt == 0 || uio->uio_resid == 0)
  468                 panic("ureadc");
  469         iov = uio->uio_iov;
  470         if (iov->iov_len == 0) {
  471                 uio->uio_iovcnt--;
  472                 uio->uio_iov++;
  473                 goto again;
  474         }
  475         switch (uio->uio_segflg) {
  476 
  477         case UIO_USERSPACE:
  478                 if (subyte(iov->iov_base, c) < 0)
  479                         return (EFAULT);
  480                 break;
  481 
  482         case UIO_SYSSPACE:
  483                 iov_base = iov->iov_base;
  484                 *iov_base = c;
  485                 iov->iov_base = iov_base;
  486                 break;
  487 
  488         case UIO_NOCOPY:
  489                 break;
  490         }
  491         iov->iov_base = (char *)iov->iov_base + 1;
  492         iov->iov_len--;
  493         uio->uio_resid--;
  494         uio->uio_offset++;
  495         return (0);
  496 }
  497 
  498 /*
  499  * General routine to allocate a hash table.
  500  */
  501 void *
  502 hashinit(elements, type, hashmask)
  503         int elements;
  504         struct malloc_type *type;
  505         u_long *hashmask;
  506 {
  507         long hashsize;
  508         LIST_HEAD(generic, generic) *hashtbl;
  509         int i;
  510 
  511         if (elements <= 0)
  512                 panic("hashinit: bad elements");
  513         for (hashsize = 1; hashsize <= elements; hashsize <<= 1)
  514                 continue;
  515         hashsize >>= 1;
  516         hashtbl = malloc((u_long)hashsize * sizeof(*hashtbl), type, M_WAITOK);
  517         for (i = 0; i < hashsize; i++)
  518                 LIST_INIT(&hashtbl[i]);
  519         *hashmask = hashsize - 1;
  520         return (hashtbl);
  521 }
  522 
  523 void
  524 hashdestroy(vhashtbl, type, hashmask)
  525         void *vhashtbl;
  526         struct malloc_type *type;
  527         u_long hashmask;
  528 {
  529         LIST_HEAD(generic, generic) *hashtbl, *hp;
  530 
  531         hashtbl = vhashtbl;
  532         for (hp = hashtbl; hp <= &hashtbl[hashmask]; hp++)
  533                 if (!LIST_EMPTY(hp))
  534                         panic("hashdestroy: hash not empty");
  535         free(hashtbl, type);
  536 }
  537 
  538 static int primes[] = { 1, 13, 31, 61, 127, 251, 509, 761, 1021, 1531, 2039,
  539                         2557, 3067, 3583, 4093, 4603, 5119, 5623, 6143, 6653,
  540                         7159, 7673, 8191, 12281, 16381, 24571, 32749 };
  541 #define NPRIMES (sizeof(primes) / sizeof(primes[0]))
  542 
  543 /*
  544  * General routine to allocate a prime number sized hash table.
  545  */
  546 void *
  547 phashinit(elements, type, nentries)
  548         int elements;
  549         struct malloc_type *type;
  550         u_long *nentries;
  551 {
  552         long hashsize;
  553         LIST_HEAD(generic, generic) *hashtbl;
  554         int i;
  555 
  556         if (elements <= 0)
  557                 panic("phashinit: bad elements");
  558         for (i = 1, hashsize = primes[1]; hashsize <= elements;) {
  559                 i++;
  560                 if (i == NPRIMES)
  561                         break;
  562                 hashsize = primes[i];
  563         }
  564         hashsize = primes[i - 1];
  565         hashtbl = malloc((u_long)hashsize * sizeof(*hashtbl), type, M_WAITOK);
  566         for (i = 0; i < hashsize; i++)
  567                 LIST_INIT(&hashtbl[i]);
  568         *nentries = hashsize;
  569         return (hashtbl);
  570 }
  571 
  572 void
  573 uio_yield()
  574 {
  575         struct thread *td;
  576 
  577         td = curthread;
  578         mtx_lock_spin(&sched_lock);
  579         DROP_GIANT();
  580         sched_prio(td, td->td_ksegrp->kg_user_pri); /* XXXKSE */
  581         td->td_proc->p_stats->p_ru.ru_nivcsw++;
  582         mi_switch();
  583         mtx_unlock_spin(&sched_lock);
  584         PICKUP_GIANT();
  585 }
  586 
  587 int
  588 copyinfrom(const void *src, void *dst, size_t len, int seg)
  589 {
  590         int error = 0;
  591 
  592         switch (seg) {
  593         case UIO_USERSPACE:
  594                 error = copyin(src, dst, len);
  595                 break;
  596         case UIO_SYSSPACE:
  597                 bcopy(src, dst, len);
  598                 break;
  599         default:
  600                 panic("copyinfrom: bad seg %d\n", seg);
  601         }
  602         return (error);
  603 }
  604 
  605 int
  606 copyinstrfrom(const void *src, void *dst, size_t len, size_t *copied, int seg)
  607 {
  608         int error = 0;
  609 
  610         switch (seg) {
  611         case UIO_USERSPACE:
  612                 error = copyinstr(src, dst, len, copied);
  613                 break;
  614         case UIO_SYSSPACE:
  615                 error = copystr(src, dst, len, copied);
  616                 break;
  617         default:
  618                 panic("copyinstrfrom: bad seg %d\n", seg);
  619         }
  620         return (error);
  621 }
Cache object: cd61b4d78a01ceeb6ecf9ddc04fa1489
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FreeBSD/Linux Kernel Cross Reference sys/kern/kern_subr.c

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