The Design and Implementation of the FreeBSD Operating System, Second Edition
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FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_conf.c

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    1 /*-
    2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
    3  *
    4  * Copyright (c) 1999-2002 Poul-Henning Kamp
    5  * All rights reserved.
    6  *
    7  * Redistribution and use in source and binary forms, with or without
    8  * modification, are permitted provided that the following conditions
    9  * are met:
   10  * 1. Redistributions of source code must retain the above copyright
   11  *    notice, this list of conditions and the following disclaimer.
   12  * 2. Redistributions in binary form must reproduce the above copyright
   13  *    notice, this list of conditions and the following disclaimer in the
   14  *    documentation and/or other materials provided with the distribution.
   15  *
   16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   26  * SUCH DAMAGE.
   27  */
   28 
   29 #include <sys/cdefs.h>
   30 __FBSDID("$FreeBSD$");
   31 
   32 #include <sys/param.h>
   33 #include <sys/kernel.h>
   34 #include <sys/systm.h>
   35 #include <sys/bio.h>
   36 #include <sys/devctl.h>
   37 #include <sys/lock.h>
   38 #include <sys/mutex.h>
   39 #include <sys/module.h>
   40 #include <sys/malloc.h>
   41 #include <sys/conf.h>
   42 #include <sys/vnode.h>
   43 #include <sys/queue.h>
   44 #include <sys/poll.h>
   45 #include <sys/sx.h>
   46 #include <sys/ctype.h>
   47 #include <sys/ucred.h>
   48 #include <sys/taskqueue.h>
   49 #include <machine/stdarg.h>
   50 
   51 #include <fs/devfs/devfs_int.h>
   52 #include <vm/vm.h>
   53 
   54 static MALLOC_DEFINE(M_DEVT, "cdev", "cdev storage");
   55 
   56 struct mtx devmtx;
   57 static void destroy_devl(struct cdev *dev);
   58 static int destroy_dev_sched_cbl(struct cdev *dev,
   59     void (*cb)(void *), void *arg);
   60 static void destroy_dev_tq(void *ctx, int pending);
   61 static int make_dev_credv(int flags, struct cdev **dres, struct cdevsw *devsw,
   62     int unit, struct ucred *cr, uid_t uid, gid_t gid, int mode, const char *fmt,
   63     va_list ap);
   64 
   65 static struct cdev_priv_list cdevp_free_list =
   66     TAILQ_HEAD_INITIALIZER(cdevp_free_list);
   67 static SLIST_HEAD(free_cdevsw, cdevsw) cdevsw_gt_post_list =
   68     SLIST_HEAD_INITIALIZER(cdevsw_gt_post_list);
   69 
   70 void
   71 dev_lock(void)
   72 {
   73 
   74         mtx_lock(&devmtx);
   75 }
   76 
   77 /*
   78  * Free all the memory collected while the cdev mutex was
   79  * locked. Since devmtx is after the system map mutex, free() cannot
   80  * be called immediately and is postponed until cdev mutex can be
   81  * dropped.
   82  */
   83 static void
   84 dev_unlock_and_free(void)
   85 {
   86         struct cdev_priv_list cdp_free;
   87         struct free_cdevsw csw_free;
   88         struct cdev_priv *cdp;
   89         struct cdevsw *csw;
   90 
   91         dev_lock_assert_locked();
   92 
   93         /*
   94          * Make the local copy of the list heads while the dev_mtx is
   95          * held. Free it later.
   96          */
   97         TAILQ_INIT(&cdp_free);
   98         TAILQ_CONCAT(&cdp_free, &cdevp_free_list, cdp_list);
   99         csw_free = cdevsw_gt_post_list;
  100         SLIST_INIT(&cdevsw_gt_post_list);
  101 
  102         mtx_unlock(&devmtx);
  103 
  104         while ((cdp = TAILQ_FIRST(&cdp_free)) != NULL) {
  105                 TAILQ_REMOVE(&cdp_free, cdp, cdp_list);
  106                 devfs_free(&cdp->cdp_c);
  107         }
  108         while ((csw = SLIST_FIRST(&csw_free)) != NULL) {
  109                 SLIST_REMOVE_HEAD(&csw_free, d_postfree_list);
  110                 free(csw, M_DEVT);
  111         }
  112 }
  113 
  114 static void
  115 dev_free_devlocked(struct cdev *cdev)
  116 {
  117         struct cdev_priv *cdp;
  118 
  119         dev_lock_assert_locked();
  120         cdp = cdev2priv(cdev);
  121         KASSERT((cdp->cdp_flags & CDP_UNREF_DTR) == 0,
  122             ("destroy_dev() was not called after delist_dev(%p)", cdev));
  123         TAILQ_INSERT_HEAD(&cdevp_free_list, cdp, cdp_list);
  124 }
  125 
  126 static void
  127 cdevsw_free_devlocked(struct cdevsw *csw)
  128 {
  129 
  130         dev_lock_assert_locked();
  131         SLIST_INSERT_HEAD(&cdevsw_gt_post_list, csw, d_postfree_list);
  132 }
  133 
  134 void
  135 dev_unlock(void)
  136 {
  137 
  138         mtx_unlock(&devmtx);
  139 }
  140 
  141 void
  142 dev_ref(struct cdev *dev)
  143 {
  144 
  145         dev_lock_assert_unlocked();
  146         mtx_lock(&devmtx);
  147         dev->si_refcount++;
  148         mtx_unlock(&devmtx);
  149 }
  150 
  151 void
  152 dev_refl(struct cdev *dev)
  153 {
  154 
  155         dev_lock_assert_locked();
  156         dev->si_refcount++;
  157 }
  158 
  159 void
  160 dev_rel(struct cdev *dev)
  161 {
  162         int flag = 0;
  163 
  164         dev_lock_assert_unlocked();
  165         dev_lock();
  166         dev->si_refcount--;
  167         KASSERT(dev->si_refcount >= 0,
  168             ("dev_rel(%s) gave negative count", devtoname(dev)));
  169         if (dev->si_devsw == NULL && dev->si_refcount == 0) {
  170                 LIST_REMOVE(dev, si_list);
  171                 flag = 1;
  172         }
  173         dev_unlock();
  174         if (flag)
  175                 devfs_free(dev);
  176 }
  177 
  178 struct cdevsw *
  179 dev_refthread(struct cdev *dev, int *ref)
  180 {
  181         struct cdevsw *csw;
  182         struct cdev_priv *cdp;
  183 
  184         dev_lock_assert_unlocked();
  185         if ((dev->si_flags & SI_ETERNAL) != 0) {
  186                 *ref = 0;
  187                 return (dev->si_devsw);
  188         }
  189         cdp = cdev2priv(dev);
  190         mtx_lock(&cdp->cdp_threadlock);
  191         csw = dev->si_devsw;
  192         if (csw != NULL) {
  193                 if ((cdp->cdp_flags & CDP_SCHED_DTR) == 0)
  194                         atomic_add_long(&dev->si_threadcount, 1);
  195                 else
  196                         csw = NULL;
  197         }
  198         mtx_unlock(&cdp->cdp_threadlock);
  199         if (csw != NULL)
  200                 *ref = 1;
  201         return (csw);
  202 }
  203 
  204 struct cdevsw *
  205 devvn_refthread(struct vnode *vp, struct cdev **devp, int *ref)
  206 {
  207         struct cdevsw *csw;
  208         struct cdev_priv *cdp;
  209         struct cdev *dev;
  210 
  211         dev_lock_assert_unlocked();
  212         if ((vp->v_vflag & VV_ETERNALDEV) != 0) {
  213                 dev = vp->v_rdev;
  214                 if (dev == NULL)
  215                         return (NULL);
  216                 KASSERT((dev->si_flags & SI_ETERNAL) != 0,
  217                     ("Not eternal cdev"));
  218                 *ref = 0;
  219                 csw = dev->si_devsw;
  220                 KASSERT(csw != NULL, ("Eternal cdev is destroyed"));
  221                 *devp = dev;
  222                 return (csw);
  223         }
  224 
  225         csw = NULL;
  226         VI_LOCK(vp);
  227         dev = vp->v_rdev;
  228         if (dev == NULL) {
  229                 VI_UNLOCK(vp);
  230                 return (NULL);
  231         }
  232         cdp = cdev2priv(dev);
  233         mtx_lock(&cdp->cdp_threadlock);
  234         if ((cdp->cdp_flags & CDP_SCHED_DTR) == 0) {
  235                 csw = dev->si_devsw;
  236                 if (csw != NULL)
  237                         atomic_add_long(&dev->si_threadcount, 1);
  238         }
  239         mtx_unlock(&cdp->cdp_threadlock);
  240         VI_UNLOCK(vp);
  241         if (csw != NULL) {
  242                 *devp = dev;
  243                 *ref = 1;
  244         }
  245         return (csw);
  246 }
  247 
  248 void    
  249 dev_relthread(struct cdev *dev, int ref)
  250 {
  251 
  252         dev_lock_assert_unlocked();
  253         if (!ref)
  254                 return;
  255         KASSERT(dev->si_threadcount > 0,
  256             ("%s threadcount is wrong", dev->si_name));
  257         atomic_subtract_rel_long(&dev->si_threadcount, 1);
  258 }
  259 
  260 int
  261 nullop(void)
  262 {
  263 
  264         return (0);
  265 }
  266 
  267 int
  268 eopnotsupp(void)
  269 {
  270 
  271         return (EOPNOTSUPP);
  272 }
  273 
  274 static int
  275 enxio(void)
  276 {
  277         return (ENXIO);
  278 }
  279 
  280 static int
  281 enodev(void)
  282 {
  283         return (ENODEV);
  284 }
  285 
  286 /* Define a dead_cdevsw for use when devices leave unexpectedly. */
  287 
  288 #define dead_open       (d_open_t *)enxio
  289 #define dead_close      (d_close_t *)enxio
  290 #define dead_read       (d_read_t *)enxio
  291 #define dead_write      (d_write_t *)enxio
  292 #define dead_ioctl      (d_ioctl_t *)enxio
  293 #define dead_poll       (d_poll_t *)enodev
  294 #define dead_mmap       (d_mmap_t *)enodev
  295 
  296 static void
  297 dead_strategy(struct bio *bp)
  298 {
  299 
  300         biofinish(bp, NULL, ENXIO);
  301 }
  302 
  303 #define dead_dump       (dumper_t *)enxio
  304 #define dead_kqfilter   (d_kqfilter_t *)enxio
  305 #define dead_mmap_single (d_mmap_single_t *)enodev
  306 
  307 static struct cdevsw dead_cdevsw = {
  308         .d_version =    D_VERSION,
  309         .d_open =       dead_open,
  310         .d_close =      dead_close,
  311         .d_read =       dead_read,
  312         .d_write =      dead_write,
  313         .d_ioctl =      dead_ioctl,
  314         .d_poll =       dead_poll,
  315         .d_mmap =       dead_mmap,
  316         .d_strategy =   dead_strategy,
  317         .d_name =       "dead",
  318         .d_dump =       dead_dump,
  319         .d_kqfilter =   dead_kqfilter,
  320         .d_mmap_single = dead_mmap_single
  321 };
  322 
  323 /* Default methods if driver does not specify method */
  324 
  325 #define null_open       (d_open_t *)nullop
  326 #define null_close      (d_close_t *)nullop
  327 #define no_read         (d_read_t *)enodev
  328 #define no_write        (d_write_t *)enodev
  329 #define no_ioctl        (d_ioctl_t *)enodev
  330 #define no_mmap         (d_mmap_t *)enodev
  331 #define no_kqfilter     (d_kqfilter_t *)enodev
  332 #define no_mmap_single  (d_mmap_single_t *)enodev
  333 
  334 static void
  335 no_strategy(struct bio *bp)
  336 {
  337 
  338         biofinish(bp, NULL, ENODEV);
  339 }
  340 
  341 static int
  342 no_poll(struct cdev *dev __unused, int events, struct thread *td __unused)
  343 {
  344 
  345         return (poll_no_poll(events));
  346 }
  347 
  348 #define no_dump         (dumper_t *)enodev
  349 
  350 static int
  351 giant_open(struct cdev *dev, int oflags, int devtype, struct thread *td)
  352 {
  353         struct cdevsw *dsw;
  354         int ref, retval;
  355 
  356         dsw = dev_refthread(dev, &ref);
  357         if (dsw == NULL)
  358                 return (ENXIO);
  359         mtx_lock(&Giant);
  360         retval = dsw->d_gianttrick->d_open(dev, oflags, devtype, td);
  361         mtx_unlock(&Giant);
  362         dev_relthread(dev, ref);
  363         return (retval);
  364 }
  365 
  366 static int
  367 giant_fdopen(struct cdev *dev, int oflags, struct thread *td, struct file *fp)
  368 {
  369         struct cdevsw *dsw;
  370         int ref, retval;
  371 
  372         dsw = dev_refthread(dev, &ref);
  373         if (dsw == NULL)
  374                 return (ENXIO);
  375         mtx_lock(&Giant);
  376         retval = dsw->d_gianttrick->d_fdopen(dev, oflags, td, fp);
  377         mtx_unlock(&Giant);
  378         dev_relthread(dev, ref);
  379         return (retval);
  380 }
  381 
  382 static int
  383 giant_close(struct cdev *dev, int fflag, int devtype, struct thread *td)
  384 {
  385         struct cdevsw *dsw;
  386         int ref, retval;
  387 
  388         dsw = dev_refthread(dev, &ref);
  389         if (dsw == NULL)
  390                 return (ENXIO);
  391         mtx_lock(&Giant);
  392         retval = dsw->d_gianttrick->d_close(dev, fflag, devtype, td);
  393         mtx_unlock(&Giant);
  394         dev_relthread(dev, ref);
  395         return (retval);
  396 }
  397 
  398 static void
  399 giant_strategy(struct bio *bp)
  400 {
  401         struct cdevsw *dsw;
  402         struct cdev *dev;
  403         int ref;
  404 
  405         dev = bp->bio_dev;
  406         dsw = dev_refthread(dev, &ref);
  407         if (dsw == NULL) {
  408                 biofinish(bp, NULL, ENXIO);
  409                 return;
  410         }
  411         mtx_lock(&Giant);
  412         dsw->d_gianttrick->d_strategy(bp);
  413         mtx_unlock(&Giant);
  414         dev_relthread(dev, ref);
  415 }
  416 
  417 static int
  418 giant_ioctl(struct cdev *dev, u_long cmd, caddr_t data, int fflag, struct thread *td)
  419 {
  420         struct cdevsw *dsw;
  421         int ref, retval;
  422 
  423         dsw = dev_refthread(dev, &ref);
  424         if (dsw == NULL)
  425                 return (ENXIO);
  426         mtx_lock(&Giant);
  427         retval = dsw->d_gianttrick->d_ioctl(dev, cmd, data, fflag, td);
  428         mtx_unlock(&Giant);
  429         dev_relthread(dev, ref);
  430         return (retval);
  431 }
  432   
  433 static int
  434 giant_read(struct cdev *dev, struct uio *uio, int ioflag)
  435 {
  436         struct cdevsw *dsw;
  437         int ref, retval;
  438 
  439         dsw = dev_refthread(dev, &ref);
  440         if (dsw == NULL)
  441                 return (ENXIO);
  442         mtx_lock(&Giant);
  443         retval = dsw->d_gianttrick->d_read(dev, uio, ioflag);
  444         mtx_unlock(&Giant);
  445         dev_relthread(dev, ref);
  446         return (retval);
  447 }
  448 
  449 static int
  450 giant_write(struct cdev *dev, struct uio *uio, int ioflag)
  451 {
  452         struct cdevsw *dsw;
  453         int ref, retval;
  454 
  455         dsw = dev_refthread(dev, &ref);
  456         if (dsw == NULL)
  457                 return (ENXIO);
  458         mtx_lock(&Giant);
  459         retval = dsw->d_gianttrick->d_write(dev, uio, ioflag);
  460         mtx_unlock(&Giant);
  461         dev_relthread(dev, ref);
  462         return (retval);
  463 }
  464 
  465 static int
  466 giant_poll(struct cdev *dev, int events, struct thread *td)
  467 {
  468         struct cdevsw *dsw;
  469         int ref, retval;
  470 
  471         dsw = dev_refthread(dev, &ref);
  472         if (dsw == NULL)
  473                 return (ENXIO);
  474         mtx_lock(&Giant);
  475         retval = dsw->d_gianttrick->d_poll(dev, events, td);
  476         mtx_unlock(&Giant);
  477         dev_relthread(dev, ref);
  478         return (retval);
  479 }
  480 
  481 static int
  482 giant_kqfilter(struct cdev *dev, struct knote *kn)
  483 {
  484         struct cdevsw *dsw;
  485         int ref, retval;
  486 
  487         dsw = dev_refthread(dev, &ref);
  488         if (dsw == NULL)
  489                 return (ENXIO);
  490         mtx_lock(&Giant);
  491         retval = dsw->d_gianttrick->d_kqfilter(dev, kn);
  492         mtx_unlock(&Giant);
  493         dev_relthread(dev, ref);
  494         return (retval);
  495 }
  496 
  497 static int
  498 giant_mmap(struct cdev *dev, vm_ooffset_t offset, vm_paddr_t *paddr, int nprot,
  499     vm_memattr_t *memattr)
  500 {
  501         struct cdevsw *dsw;
  502         int ref, retval;
  503 
  504         dsw = dev_refthread(dev, &ref);
  505         if (dsw == NULL)
  506                 return (ENXIO);
  507         mtx_lock(&Giant);
  508         retval = dsw->d_gianttrick->d_mmap(dev, offset, paddr, nprot,
  509             memattr);
  510         mtx_unlock(&Giant);
  511         dev_relthread(dev, ref);
  512         return (retval);
  513 }
  514 
  515 static int
  516 giant_mmap_single(struct cdev *dev, vm_ooffset_t *offset, vm_size_t size,
  517     vm_object_t *object, int nprot)
  518 {
  519         struct cdevsw *dsw;
  520         int ref, retval;
  521 
  522         dsw = dev_refthread(dev, &ref);
  523         if (dsw == NULL)
  524                 return (ENXIO);
  525         mtx_lock(&Giant);
  526         retval = dsw->d_gianttrick->d_mmap_single(dev, offset, size, object,
  527             nprot);
  528         mtx_unlock(&Giant);
  529         dev_relthread(dev, ref);
  530         return (retval);
  531 }
  532 
  533 static void
  534 notify(struct cdev *dev, const char *ev, int flags)
  535 {
  536         static const char prefix[] = "cdev=";
  537         char *data;
  538         int namelen, mflags;
  539 
  540         if (cold)
  541                 return;
  542         mflags = (flags & MAKEDEV_NOWAIT) ? M_NOWAIT : M_WAITOK;
  543         namelen = strlen(dev->si_name);
  544         data = malloc(namelen + sizeof(prefix), M_TEMP, mflags);
  545         if (data == NULL)
  546                 return;
  547         memcpy(data, prefix, sizeof(prefix) - 1);
  548         memcpy(data + sizeof(prefix) - 1, dev->si_name, namelen + 1);
  549         devctl_notify("DEVFS", "CDEV", ev, data);
  550         free(data, M_TEMP);
  551 }
  552 
  553 static void
  554 notify_create(struct cdev *dev, int flags)
  555 {
  556 
  557         notify(dev, "CREATE", flags);
  558 }
  559 
  560 static void
  561 notify_destroy(struct cdev *dev)
  562 {
  563 
  564         notify(dev, "DESTROY", MAKEDEV_WAITOK);
  565 }
  566 
  567 static struct cdev *
  568 newdev(struct make_dev_args *args, struct cdev *si)
  569 {
  570         struct cdev *si2;
  571         struct cdevsw *csw;
  572 
  573         dev_lock_assert_locked();
  574         csw = args->mda_devsw;
  575         si2 = NULL;
  576         if (csw->d_flags & D_NEEDMINOR) {
  577                 /* We may want to return an existing device */
  578                 LIST_FOREACH(si2, &csw->d_devs, si_list) {
  579                         if (dev2unit(si2) == args->mda_unit) {
  580                                 dev_free_devlocked(si);
  581                                 si = si2;
  582                                 break;
  583                         }
  584                 }
  585 
  586                 /*
  587                  * If we're returning an existing device, we should make sure
  588                  * it isn't already initialized.  This would have been caught
  589                  * in consumers anyways, but it's good to catch such a case
  590                  * early.  We still need to complete initialization of the
  591                  * device, and we'll use whatever make_dev_args were passed in
  592                  * to do so.
  593                  */
  594                 KASSERT(si2 == NULL || (si2->si_flags & SI_NAMED) == 0,
  595                     ("make_dev() by driver %s on pre-existing device (min=%x, name=%s)",
  596                     args->mda_devsw->d_name, dev2unit(si2), devtoname(si2)));
  597         }
  598         si->si_drv0 = args->mda_unit;
  599         si->si_drv1 = args->mda_si_drv1;
  600         si->si_drv2 = args->mda_si_drv2;
  601         /* Only push to csw->d_devs if it's not a cloned device. */
  602         if (si2 == NULL) {
  603                 si->si_devsw = csw;
  604                 LIST_INSERT_HEAD(&csw->d_devs, si, si_list);
  605         } else {
  606                 KASSERT(si->si_devsw == csw,
  607                     ("%s: inconsistent devsw between clone_create() and make_dev()",
  608                     __func__));
  609         }
  610         return (si);
  611 }
  612 
  613 static void
  614 fini_cdevsw(struct cdevsw *devsw)
  615 {
  616         struct cdevsw *gt;
  617 
  618         if (devsw->d_gianttrick != NULL) {
  619                 gt = devsw->d_gianttrick;
  620                 memcpy(devsw, gt, sizeof *devsw);
  621                 cdevsw_free_devlocked(gt);
  622                 devsw->d_gianttrick = NULL;
  623         }
  624         devsw->d_flags &= ~D_INIT;
  625 }
  626 
  627 static int
  628 prep_cdevsw(struct cdevsw *devsw, int flags)
  629 {
  630         struct cdevsw *dsw2;
  631 
  632         dev_lock_assert_locked();
  633         if (devsw->d_flags & D_INIT)
  634                 return (0);
  635         if (devsw->d_flags & D_NEEDGIANT) {
  636                 dev_unlock();
  637                 dsw2 = malloc(sizeof *dsw2, M_DEVT,
  638                      (flags & MAKEDEV_NOWAIT) ? M_NOWAIT : M_WAITOK);
  639                 dev_lock();
  640                 if (dsw2 == NULL && !(devsw->d_flags & D_INIT))
  641                         return (ENOMEM);
  642         } else
  643                 dsw2 = NULL;
  644         if (devsw->d_flags & D_INIT) {
  645                 if (dsw2 != NULL)
  646                         cdevsw_free_devlocked(dsw2);
  647                 return (0);
  648         }
  649 
  650         if (devsw->d_version != D_VERSION_04) {
  651                 printf(
  652                     "WARNING: Device driver \"%s\" has wrong version %s\n",
  653                     devsw->d_name == NULL ? "???" : devsw->d_name,
  654                     "and is disabled.  Recompile KLD module.");
  655                 devsw->d_open = dead_open;
  656                 devsw->d_close = dead_close;
  657                 devsw->d_read = dead_read;
  658                 devsw->d_write = dead_write;
  659                 devsw->d_ioctl = dead_ioctl;
  660                 devsw->d_poll = dead_poll;
  661                 devsw->d_mmap = dead_mmap;
  662                 devsw->d_mmap_single = dead_mmap_single;
  663                 devsw->d_strategy = dead_strategy;
  664                 devsw->d_dump = dead_dump;
  665                 devsw->d_kqfilter = dead_kqfilter;
  666         }
  667 
  668         if ((devsw->d_flags & D_NEEDGIANT) != 0) {
  669                 if ((devsw->d_flags & D_GIANTOK) == 0) {
  670                         printf(
  671                             "WARNING: Device \"%s\" is Giant locked and may be "
  672                             "deleted before FreeBSD 14.0.\n",
  673                             devsw->d_name == NULL ? "???" : devsw->d_name);
  674                 }
  675                 if (devsw->d_gianttrick == NULL) {
  676                         memcpy(dsw2, devsw, sizeof *dsw2);
  677                         devsw->d_gianttrick = dsw2;
  678                         dsw2 = NULL;
  679                 }
  680         }
  681 
  682 #define FIXUP(member, noop, giant)                              \
  683         do {                                                    \
  684                 if (devsw->member == NULL) {                    \
  685                         devsw->member = noop;                   \
  686                 } else if (devsw->d_flags & D_NEEDGIANT)        \
  687                         devsw->member = giant;                  \
  688                 }                                               \
  689         while (0)
  690 
  691         FIXUP(d_open,           null_open,      giant_open);
  692         FIXUP(d_fdopen,         NULL,           giant_fdopen);
  693         FIXUP(d_close,          null_close,     giant_close);
  694         FIXUP(d_read,           no_read,        giant_read);
  695         FIXUP(d_write,          no_write,       giant_write);
  696         FIXUP(d_ioctl,          no_ioctl,       giant_ioctl);
  697         FIXUP(d_poll,           no_poll,        giant_poll);
  698         FIXUP(d_mmap,           no_mmap,        giant_mmap);
  699         FIXUP(d_strategy,       no_strategy,    giant_strategy);
  700         FIXUP(d_kqfilter,       no_kqfilter,    giant_kqfilter);
  701         FIXUP(d_mmap_single,    no_mmap_single, giant_mmap_single);
  702 
  703         if (devsw->d_dump == NULL)      devsw->d_dump = no_dump;
  704 
  705         LIST_INIT(&devsw->d_devs);
  706 
  707         devsw->d_flags |= D_INIT;
  708 
  709         if (dsw2 != NULL)
  710                 cdevsw_free_devlocked(dsw2);
  711         return (0);
  712 }
  713 
  714 static int
  715 prep_devname(struct cdev *dev, const char *fmt, va_list ap)
  716 {
  717         int len;
  718         char *from, *q, *s, *to;
  719 
  720         dev_lock_assert_locked();
  721 
  722         len = vsnrprintf(dev->si_name, sizeof(dev->si_name), 32, fmt, ap);
  723         if (len > sizeof(dev->si_name) - 1)
  724                 return (ENAMETOOLONG);
  725 
  726         /* Strip leading slashes. */
  727         for (from = dev->si_name; *from == '/'; from++)
  728                 ;
  729 
  730         for (to = dev->si_name; *from != '\0'; from++, to++) {
  731                 /*
  732                  * Spaces and double quotation marks cause
  733                  * problems for the devctl(4) protocol.
  734                  * Reject names containing those characters.
  735                  */
  736                 if (isspace(*from) || *from == '"')
  737                         return (EINVAL);
  738                 /* Treat multiple sequential slashes as single. */
  739                 while (from[0] == '/' && from[1] == '/')
  740                         from++;
  741                 /* Trailing slash is considered invalid. */
  742                 if (from[0] == '/' && from[1] == '\0')
  743                         return (EINVAL);
  744                 *to = *from;
  745         }
  746         *to = '\0';
  747 
  748         if (dev->si_name[0] == '\0')
  749                 return (EINVAL);
  750 
  751         /* Disallow "." and ".." components. */
  752         for (s = dev->si_name;;) {
  753                 for (q = s; *q != '/' && *q != '\0'; q++)
  754                         ;
  755                 if (q - s == 1 && s[0] == '.')
  756                         return (EINVAL);
  757                 if (q - s == 2 && s[0] == '.' && s[1] == '.')
  758                         return (EINVAL);
  759                 if (*q != '/')
  760                         break;
  761                 s = q + 1;
  762         }
  763 
  764         if (devfs_dev_exists(dev->si_name) != 0)
  765                 return (EEXIST);
  766 
  767         return (0);
  768 }
  769 
  770 void
  771 make_dev_args_init_impl(struct make_dev_args *args, size_t sz)
  772 {
  773 
  774         bzero(args, sz);
  775         args->mda_size = sz;
  776 }
  777 
  778 static int
  779 make_dev_sv(struct make_dev_args *args1, struct cdev **dres,
  780     const char *fmt, va_list ap)
  781 {
  782         struct cdev *dev, *dev_new;
  783         struct make_dev_args args;
  784         int res;
  785 
  786         bzero(&args, sizeof(args));
  787         if (sizeof(args) < args1->mda_size)
  788                 return (EINVAL);
  789         bcopy(args1, &args, args1->mda_size);
  790         KASSERT((args.mda_flags & MAKEDEV_WAITOK) == 0 ||
  791             (args.mda_flags & MAKEDEV_NOWAIT) == 0,
  792             ("make_dev_sv: both WAITOK and NOWAIT specified"));
  793         dev_new = devfs_alloc(args.mda_flags);
  794         if (dev_new == NULL)
  795                 return (ENOMEM);
  796         dev_lock();
  797         res = prep_cdevsw(args.mda_devsw, args.mda_flags);
  798         if (res != 0) {
  799                 dev_unlock();
  800                 devfs_free(dev_new);
  801                 return (res);
  802         }
  803         dev = newdev(&args, dev_new);
  804         if ((dev->si_flags & SI_NAMED) == 0) {
  805                 res = prep_devname(dev, fmt, ap);
  806                 if (res != 0) {
  807                         if ((args.mda_flags & MAKEDEV_CHECKNAME) == 0) {
  808                                 panic(
  809                         "make_dev_sv: bad si_name (error=%d, si_name=%s)",
  810                                     res, dev->si_name);
  811                         }
  812                         if (dev == dev_new) {
  813                                 LIST_REMOVE(dev, si_list);
  814                                 dev_unlock();
  815                                 devfs_free(dev);
  816                         } else
  817                                 dev_unlock();
  818                         return (res);
  819                 }
  820         }
  821         if ((args.mda_flags & MAKEDEV_REF) != 0)
  822                 dev_refl(dev);
  823         if ((args.mda_flags & MAKEDEV_ETERNAL) != 0)
  824                 dev->si_flags |= SI_ETERNAL;
  825         KASSERT(!(dev->si_flags & SI_NAMED),
  826             ("make_dev() by driver %s on pre-existing device (min=%x, name=%s)",
  827             args.mda_devsw->d_name, dev2unit(dev), devtoname(dev)));
  828         dev->si_flags |= SI_NAMED;
  829         if (args.mda_cr != NULL)
  830                 dev->si_cred = crhold(args.mda_cr);
  831         dev->si_uid = args.mda_uid;
  832         dev->si_gid = args.mda_gid;
  833         dev->si_mode = args.mda_mode;
  834 
  835         devfs_create(dev);
  836         clean_unrhdrl(devfs_inos);
  837         dev_unlock_and_free();
  838 
  839         notify_create(dev, args.mda_flags);
  840 
  841         *dres = dev;
  842         return (0);
  843 }
  844 
  845 int
  846 make_dev_s(struct make_dev_args *args, struct cdev **dres,
  847     const char *fmt, ...)
  848 {
  849         va_list ap;
  850         int res;
  851 
  852         va_start(ap, fmt);
  853         res = make_dev_sv(args, dres, fmt, ap);
  854         va_end(ap);
  855         return (res);
  856 }
  857 
  858 static int
  859 make_dev_credv(int flags, struct cdev **dres, struct cdevsw *devsw, int unit,
  860     struct ucred *cr, uid_t uid, gid_t gid, int mode, const char *fmt,
  861     va_list ap)
  862 {
  863         struct make_dev_args args;
  864 
  865         make_dev_args_init(&args);
  866         args.mda_flags = flags;
  867         args.mda_devsw = devsw;
  868         args.mda_cr = cr;
  869         args.mda_uid = uid;
  870         args.mda_gid = gid;
  871         args.mda_mode = mode;
  872         args.mda_unit = unit;
  873         return (make_dev_sv(&args, dres, fmt, ap));
  874 }
  875 
  876 struct cdev *
  877 make_dev(struct cdevsw *devsw, int unit, uid_t uid, gid_t gid, int mode,
  878     const char *fmt, ...)
  879 {
  880         struct cdev *dev;
  881         va_list ap;
  882         int res __unused;
  883 
  884         va_start(ap, fmt);
  885         res = make_dev_credv(0, &dev, devsw, unit, NULL, uid, gid, mode, fmt,
  886                       ap);
  887         va_end(ap);
  888         KASSERT(res == 0 && dev != NULL,
  889             ("make_dev: failed make_dev_credv (error=%d)", res));
  890         return (dev);
  891 }
  892 
  893 struct cdev *
  894 make_dev_cred(struct cdevsw *devsw, int unit, struct ucred *cr, uid_t uid,
  895     gid_t gid, int mode, const char *fmt, ...)
  896 {
  897         struct cdev *dev;
  898         va_list ap;
  899         int res __unused;
  900 
  901         va_start(ap, fmt);
  902         res = make_dev_credv(0, &dev, devsw, unit, cr, uid, gid, mode, fmt, ap);
  903         va_end(ap);
  904 
  905         KASSERT(res == 0 && dev != NULL,
  906             ("make_dev_cred: failed make_dev_credv (error=%d)", res));
  907         return (dev);
  908 }
  909 
  910 struct cdev *
  911 make_dev_credf(int flags, struct cdevsw *devsw, int unit, struct ucred *cr,
  912     uid_t uid, gid_t gid, int mode, const char *fmt, ...)
  913 {
  914         struct cdev *dev;
  915         va_list ap;
  916         int res;
  917 
  918         va_start(ap, fmt);
  919         res = make_dev_credv(flags, &dev, devsw, unit, cr, uid, gid, mode,
  920             fmt, ap);
  921         va_end(ap);
  922 
  923         KASSERT(((flags & MAKEDEV_NOWAIT) != 0 && res == ENOMEM) ||
  924             ((flags & MAKEDEV_CHECKNAME) != 0 && res != ENOMEM) || res == 0,
  925             ("make_dev_credf: failed make_dev_credv (error=%d)", res));
  926         return (res == 0 ? dev : NULL);
  927 }
  928 
  929 int
  930 make_dev_p(int flags, struct cdev **cdev, struct cdevsw *devsw,
  931     struct ucred *cr, uid_t uid, gid_t gid, int mode, const char *fmt, ...)
  932 {
  933         va_list ap;
  934         int res;
  935 
  936         va_start(ap, fmt);
  937         res = make_dev_credv(flags, cdev, devsw, 0, cr, uid, gid, mode,
  938             fmt, ap);
  939         va_end(ap);
  940 
  941         KASSERT(((flags & MAKEDEV_NOWAIT) != 0 && res == ENOMEM) ||
  942             ((flags & MAKEDEV_CHECKNAME) != 0 && res != ENOMEM) || res == 0,
  943             ("make_dev_p: failed make_dev_credv (error=%d)", res));
  944         return (res);
  945 }
  946 
  947 static void
  948 dev_dependsl(struct cdev *pdev, struct cdev *cdev)
  949 {
  950 
  951         cdev->si_parent = pdev;
  952         cdev->si_flags |= SI_CHILD;
  953         LIST_INSERT_HEAD(&pdev->si_children, cdev, si_siblings);
  954 }
  955 
  956 void
  957 dev_depends(struct cdev *pdev, struct cdev *cdev)
  958 {
  959 
  960         dev_lock();
  961         dev_dependsl(pdev, cdev);
  962         dev_unlock();
  963 }
  964 
  965 static int
  966 make_dev_alias_v(int flags, struct cdev **cdev, struct cdev *pdev,
  967     const char *fmt, va_list ap)
  968 {
  969         struct cdev *dev;
  970         int error;
  971 
  972         KASSERT(pdev != NULL, ("make_dev_alias_v: pdev is NULL"));
  973         KASSERT((flags & MAKEDEV_WAITOK) == 0 || (flags & MAKEDEV_NOWAIT) == 0,
  974             ("make_dev_alias_v: both WAITOK and NOWAIT specified"));
  975         KASSERT((flags & ~(MAKEDEV_WAITOK | MAKEDEV_NOWAIT |
  976             MAKEDEV_CHECKNAME)) == 0,
  977             ("make_dev_alias_v: invalid flags specified (flags=%02x)", flags));
  978 
  979         dev = devfs_alloc(flags);
  980         if (dev == NULL)
  981                 return (ENOMEM);
  982         dev_lock();
  983         dev->si_flags |= SI_ALIAS;
  984         error = prep_devname(dev, fmt, ap);
  985         if (error != 0) {
  986                 if ((flags & MAKEDEV_CHECKNAME) == 0) {
  987                         panic("make_dev_alias_v: bad si_name "
  988                             "(error=%d, si_name=%s)", error, dev->si_name);
  989                 }
  990                 dev_unlock();
  991                 devfs_free(dev);
  992                 return (error);
  993         }
  994         dev->si_flags |= SI_NAMED;
  995         devfs_create(dev);
  996         dev_dependsl(pdev, dev);
  997         clean_unrhdrl(devfs_inos);
  998         dev_unlock();
  999 
 1000         notify_create(dev, flags);
 1001         *cdev = dev;
 1002 
 1003         return (0);
 1004 }
 1005 
 1006 struct cdev *
 1007 make_dev_alias(struct cdev *pdev, const char *fmt, ...)
 1008 {
 1009         struct cdev *dev;
 1010         va_list ap;
 1011         int res __unused;
 1012 
 1013         va_start(ap, fmt);
 1014         res = make_dev_alias_v(MAKEDEV_WAITOK, &dev, pdev, fmt, ap);
 1015         va_end(ap);
 1016 
 1017         KASSERT(res == 0 && dev != NULL,
 1018             ("make_dev_alias: failed make_dev_alias_v (error=%d)", res));
 1019         return (dev);
 1020 }
 1021 
 1022 int
 1023 make_dev_alias_p(int flags, struct cdev **cdev, struct cdev *pdev,
 1024     const char *fmt, ...)
 1025 {
 1026         va_list ap;
 1027         int res;
 1028 
 1029         va_start(ap, fmt);
 1030         res = make_dev_alias_v(flags, cdev, pdev, fmt, ap);
 1031         va_end(ap);
 1032         return (res);
 1033 }
 1034 
 1035 int
 1036 make_dev_physpath_alias(int flags, struct cdev **cdev, struct cdev *pdev, 
 1037     struct cdev *old_alias, const char *physpath)
 1038 {
 1039         char *devfspath;
 1040         int physpath_len;
 1041         int max_parentpath_len;
 1042         int parentpath_len;
 1043         int devfspathbuf_len;
 1044         int mflags;
 1045         int ret;
 1046 
 1047         *cdev = NULL;
 1048         devfspath = NULL;
 1049         physpath_len = strlen(physpath);
 1050         ret = EINVAL;
 1051         if (physpath_len == 0)
 1052                 goto out;
 1053 
 1054         if (strncmp("id1,", physpath, 4) == 0) {
 1055                 physpath += 4;
 1056                 physpath_len -= 4;
 1057                 if (physpath_len == 0)
 1058                         goto out;
 1059         }
 1060 
 1061         max_parentpath_len = SPECNAMELEN - physpath_len - /*/*/1;
 1062         parentpath_len = strlen(pdev->si_name);
 1063         if (max_parentpath_len < parentpath_len) {
 1064                 if (bootverbose)
 1065                         printf("WARNING: Unable to alias %s "
 1066                             "to %s/%s - path too long\n",
 1067                             pdev->si_name, physpath, pdev->si_name);
 1068                 ret = ENAMETOOLONG;
 1069                 goto out;
 1070         }
 1071 
 1072         mflags = (flags & MAKEDEV_NOWAIT) ? M_NOWAIT : M_WAITOK;
 1073         devfspathbuf_len = physpath_len + /*/*/1 + parentpath_len + /*NUL*/1;
 1074         devfspath = malloc(devfspathbuf_len, M_DEVBUF, mflags);
 1075         if (devfspath == NULL) {
 1076                 ret = ENOMEM;
 1077                 goto out;
 1078         }
 1079 
 1080         sprintf(devfspath, "%s/%s", physpath, pdev->si_name);
 1081         if (old_alias != NULL && strcmp(old_alias->si_name, devfspath) == 0) {
 1082                 /* Retain the existing alias. */
 1083                 *cdev = old_alias;
 1084                 old_alias = NULL;
 1085                 ret = 0;
 1086         } else {
 1087                 ret = make_dev_alias_p(flags, cdev, pdev, "%s", devfspath);
 1088         }
 1089 out:
 1090         if (old_alias != NULL)  
 1091                 destroy_dev(old_alias);
 1092         if (devfspath != NULL)
 1093                 free(devfspath, M_DEVBUF);
 1094         return (ret);
 1095 }
 1096 
 1097 static void
 1098 destroy_devl(struct cdev *dev)
 1099 {
 1100         struct cdevsw *csw;
 1101         struct cdev_privdata *p;
 1102         struct cdev_priv *cdp;
 1103 
 1104         dev_lock_assert_locked();
 1105         KASSERT(dev->si_flags & SI_NAMED,
 1106             ("WARNING: Driver mistake: destroy_dev on %d\n", dev2unit(dev)));
 1107         KASSERT((dev->si_flags & SI_ETERNAL) == 0,
 1108             ("WARNING: Driver mistake: destroy_dev on eternal %d\n",
 1109              dev2unit(dev)));
 1110 
 1111         cdp = cdev2priv(dev);
 1112         if ((cdp->cdp_flags & CDP_UNREF_DTR) == 0) {
 1113                 /*
 1114                  * Avoid race with dev_rel(), e.g. from the populate
 1115                  * loop.  If CDP_UNREF_DTR flag is set, the reference
 1116                  * to be dropped at the end of destroy_devl() was
 1117                  * already taken by delist_dev_locked().
 1118                  */
 1119                 dev_refl(dev);
 1120 
 1121                 devfs_destroy(dev);
 1122         }
 1123 
 1124         /* Remove name marking */
 1125         dev->si_flags &= ~SI_NAMED;
 1126 
 1127         /* If we are a child, remove us from the parents list */
 1128         if (dev->si_flags & SI_CHILD) {
 1129                 LIST_REMOVE(dev, si_siblings);
 1130                 dev->si_flags &= ~SI_CHILD;
 1131         }
 1132 
 1133         /* Kill our children */
 1134         while (!LIST_EMPTY(&dev->si_children))
 1135                 destroy_devl(LIST_FIRST(&dev->si_children));
 1136 
 1137         /* Remove from clone list */
 1138         if (dev->si_flags & SI_CLONELIST) {
 1139                 LIST_REMOVE(dev, si_clone);
 1140                 dev->si_flags &= ~SI_CLONELIST;
 1141         }
 1142 
 1143         mtx_lock(&cdp->cdp_threadlock);
 1144         csw = dev->si_devsw;
 1145         dev->si_devsw = NULL;   /* already NULL for SI_ALIAS */
 1146         while (csw != NULL && csw->d_purge != NULL && dev->si_threadcount) {
 1147                 csw->d_purge(dev);
 1148                 mtx_unlock(&cdp->cdp_threadlock);
 1149                 msleep(csw, &devmtx, PRIBIO, "devprg", hz/10);
 1150                 mtx_lock(&cdp->cdp_threadlock);
 1151                 if (dev->si_threadcount)
 1152                         printf("Still %lu threads in %s\n",
 1153                             dev->si_threadcount, devtoname(dev));
 1154         }
 1155         while (dev->si_threadcount != 0) {
 1156                 /* Use unique dummy wait ident */
 1157                 mtx_unlock(&cdp->cdp_threadlock);
 1158                 msleep(&csw, &devmtx, PRIBIO, "devdrn", hz / 10);
 1159                 mtx_lock(&cdp->cdp_threadlock);
 1160         }
 1161 
 1162         mtx_unlock(&cdp->cdp_threadlock);
 1163         dev_unlock();
 1164         if ((cdp->cdp_flags & CDP_UNREF_DTR) == 0) {
 1165                 /* avoid out of order notify events */
 1166                 notify_destroy(dev);
 1167         }
 1168         mtx_lock(&cdevpriv_mtx);
 1169         while ((p = LIST_FIRST(&cdp->cdp_fdpriv)) != NULL) {
 1170                 devfs_destroy_cdevpriv(p);
 1171                 mtx_lock(&cdevpriv_mtx);
 1172         }
 1173         mtx_unlock(&cdevpriv_mtx);
 1174         dev_lock();
 1175 
 1176         dev->si_drv1 = 0;
 1177         dev->si_drv2 = 0;
 1178 
 1179         if (!(dev->si_flags & SI_ALIAS)) {
 1180                 /* Remove from cdevsw list */
 1181                 LIST_REMOVE(dev, si_list);
 1182 
 1183                 /* If cdevsw has no more struct cdev *'s, clean it */
 1184                 if (LIST_EMPTY(&csw->d_devs)) {
 1185                         fini_cdevsw(csw);
 1186                         wakeup(&csw->d_devs);
 1187                 }
 1188         }
 1189         dev->si_flags &= ~SI_ALIAS;
 1190         cdp->cdp_flags &= ~CDP_UNREF_DTR;
 1191         dev->si_refcount--;
 1192 
 1193         if (dev->si_refcount > 0)
 1194                 LIST_INSERT_HEAD(&dead_cdevsw.d_devs, dev, si_list);
 1195         else
 1196                 dev_free_devlocked(dev);
 1197 }
 1198 
 1199 static void
 1200 delist_dev_locked(struct cdev *dev)
 1201 {
 1202         struct cdev_priv *cdp;
 1203         struct cdev *child;
 1204 
 1205         dev_lock_assert_locked();
 1206         cdp = cdev2priv(dev);
 1207         if ((cdp->cdp_flags & CDP_UNREF_DTR) != 0)
 1208                 return;
 1209         cdp->cdp_flags |= CDP_UNREF_DTR;
 1210         dev_refl(dev);
 1211         devfs_destroy(dev);
 1212         LIST_FOREACH(child, &dev->si_children, si_siblings)
 1213                 delist_dev_locked(child);
 1214         dev_unlock();   
 1215         /* ensure the destroy event is queued in order */
 1216         notify_destroy(dev);
 1217         dev_lock();
 1218 }
 1219 
 1220 /*
 1221  * This function will delist a character device and its children from
 1222  * the directory listing and create a destroy event without waiting
 1223  * for all character device references to go away. At some later point
 1224  * destroy_dev() must be called to complete the character device
 1225  * destruction. After calling this function the character device name
 1226  * can instantly be re-used.
 1227  */
 1228 void
 1229 delist_dev(struct cdev *dev)
 1230 {
 1231 
 1232         WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, "delist_dev");
 1233         dev_lock();
 1234         delist_dev_locked(dev);
 1235         dev_unlock();
 1236 }
 1237 
 1238 void
 1239 destroy_dev(struct cdev *dev)
 1240 {
 1241 
 1242         WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, "destroy_dev");
 1243         dev_lock();
 1244         destroy_devl(dev);
 1245         dev_unlock_and_free();
 1246 }
 1247 
 1248 const char *
 1249 devtoname(struct cdev *dev)
 1250 {
 1251 
 1252         return (dev->si_name);
 1253 }
 1254 
 1255 int
 1256 dev_stdclone(char *name, char **namep, const char *stem, int *unit)
 1257 {
 1258         int u, i;
 1259 
 1260         i = strlen(stem);
 1261         if (strncmp(stem, name, i) != 0)
 1262                 return (0);
 1263         if (!isdigit(name[i]))
 1264                 return (0);
 1265         u = 0;
 1266         if (name[i] == '' && isdigit(name[i+1]))
 1267                 return (0);
 1268         while (isdigit(name[i])) {
 1269                 u *= 10;
 1270                 u += name[i++] - '';
 1271         }
 1272         if (u > 0xffffff)
 1273                 return (0);
 1274         *unit = u;
 1275         if (namep)
 1276                 *namep = &name[i];
 1277         if (name[i]) 
 1278                 return (2);
 1279         return (1);
 1280 }
 1281 
 1282 /*
 1283  * Helper functions for cloning device drivers.
 1284  *
 1285  * The objective here is to make it unnecessary for the device drivers to
 1286  * use rman or similar to manage their unit number space.  Due to the way
 1287  * we do "on-demand" devices, using rman or other "private" methods 
 1288  * will be very tricky to lock down properly once we lock down this file.
 1289  *
 1290  * Instead we give the drivers these routines which puts the struct cdev *'s
 1291  * that are to be managed on their own list, and gives the driver the ability
 1292  * to ask for the first free unit number or a given specified unit number.
 1293  *
 1294  * In addition these routines support paired devices (pty, nmdm and similar)
 1295  * by respecting a number of "flag" bits in the minor number.
 1296  *
 1297  */
 1298 
 1299 struct clonedevs {
 1300         LIST_HEAD(,cdev)        head;
 1301 };
 1302 
 1303 void
 1304 clone_setup(struct clonedevs **cdp)
 1305 {
 1306 
 1307         *cdp = malloc(sizeof **cdp, M_DEVBUF, M_WAITOK | M_ZERO);
 1308         LIST_INIT(&(*cdp)->head);
 1309 }
 1310 
 1311 int
 1312 clone_create(struct clonedevs **cdp, struct cdevsw *csw, int *up,
 1313     struct cdev **dp, int extra)
 1314 {
 1315         struct clonedevs *cd;
 1316         struct cdev *dev, *ndev, *dl, *de;
 1317         struct make_dev_args args;
 1318         int unit, low, u;
 1319 
 1320         KASSERT(*cdp != NULL,
 1321             ("clone_setup() not called in driver \"%s\"", csw->d_name));
 1322         KASSERT(!(extra & CLONE_UNITMASK),
 1323             ("Illegal extra bits (0x%x) in clone_create", extra));
 1324         KASSERT(*up <= CLONE_UNITMASK,
 1325             ("Too high unit (0x%x) in clone_create", *up));
 1326         KASSERT(csw->d_flags & D_NEEDMINOR,
 1327             ("clone_create() on cdevsw without minor numbers"));
 1328 
 1329         /*
 1330          * Search the list for a lot of things in one go:
 1331          *   A preexisting match is returned immediately.
 1332          *   The lowest free unit number if we are passed -1, and the place
 1333          *       in the list where we should insert that new element.
 1334          *   The place to insert a specified unit number, if applicable
 1335          *       the end of the list.
 1336          */
 1337         unit = *up;
 1338         ndev = devfs_alloc(MAKEDEV_WAITOK);
 1339         dev_lock();
 1340         prep_cdevsw(csw, MAKEDEV_WAITOK);
 1341         low = extra;
 1342         de = dl = NULL;
 1343         cd = *cdp;
 1344         LIST_FOREACH(dev, &cd->head, si_clone) {
 1345                 KASSERT(dev->si_flags & SI_CLONELIST,
 1346                     ("Dev %p(%s) should be on clonelist", dev, dev->si_name));
 1347                 u = dev2unit(dev);
 1348                 if (u == (unit | extra)) {
 1349                         *dp = dev;
 1350                         dev_unlock();
 1351                         devfs_free(ndev);
 1352                         return (0);
 1353                 }
 1354                 if (unit == -1 && u == low) {
 1355                         low++;
 1356                         de = dev;
 1357                         continue;
 1358                 } else if (u < (unit | extra)) {
 1359                         de = dev;
 1360                         continue;
 1361                 } else if (u > (unit | extra)) {
 1362                         dl = dev;
 1363                         break;
 1364                 }
 1365         }
 1366         if (unit == -1)
 1367                 unit = low & CLONE_UNITMASK;
 1368         make_dev_args_init(&args);
 1369         args.mda_unit = unit | extra;
 1370         args.mda_devsw = csw;
 1371         dev = newdev(&args, ndev);
 1372         if (dev->si_flags & SI_CLONELIST) {
 1373                 printf("dev %p (%s) is on clonelist\n", dev, dev->si_name);
 1374                 printf("unit=%d, low=%d, extra=0x%x\n", unit, low, extra);
 1375                 LIST_FOREACH(dev, &cd->head, si_clone) {
 1376                         printf("\t%p %s\n", dev, dev->si_name);
 1377                 }
 1378                 panic("foo");
 1379         }
 1380         KASSERT(!(dev->si_flags & SI_CLONELIST),
 1381             ("Dev %p(%s) should not be on clonelist", dev, dev->si_name));
 1382         if (dl != NULL)
 1383                 LIST_INSERT_BEFORE(dl, dev, si_clone);
 1384         else if (de != NULL)
 1385                 LIST_INSERT_AFTER(de, dev, si_clone);
 1386         else
 1387                 LIST_INSERT_HEAD(&cd->head, dev, si_clone);
 1388         dev->si_flags |= SI_CLONELIST;
 1389         *up = unit;
 1390         dev_unlock_and_free();
 1391         return (1);
 1392 }
 1393 
 1394 /*
 1395  * Kill everything still on the list.  The driver should already have
 1396  * disposed of any softc hung of the struct cdev *'s at this time.
 1397  */
 1398 void
 1399 clone_cleanup(struct clonedevs **cdp)
 1400 {
 1401         struct cdev *dev;
 1402         struct cdev_priv *cp;
 1403         struct clonedevs *cd;
 1404 
 1405         cd = *cdp;
 1406         if (cd == NULL)
 1407                 return;
 1408         dev_lock();
 1409         while (!LIST_EMPTY(&cd->head)) {
 1410                 dev = LIST_FIRST(&cd->head);
 1411                 LIST_REMOVE(dev, si_clone);
 1412                 KASSERT(dev->si_flags & SI_CLONELIST,
 1413                     ("Dev %p(%s) should be on clonelist", dev, dev->si_name));
 1414                 dev->si_flags &= ~SI_CLONELIST;
 1415                 cp = cdev2priv(dev);
 1416                 if (!(cp->cdp_flags & CDP_SCHED_DTR)) {
 1417                         cp->cdp_flags |= CDP_SCHED_DTR;
 1418                         KASSERT(dev->si_flags & SI_NAMED,
 1419                                 ("Driver has goofed in cloning underways udev %jx unit %x",
 1420                                 (uintmax_t)dev2udev(dev), dev2unit(dev)));
 1421                         destroy_devl(dev);
 1422                 }
 1423         }
 1424         dev_unlock_and_free();
 1425         free(cd, M_DEVBUF);
 1426         *cdp = NULL;
 1427 }
 1428 
 1429 static TAILQ_HEAD(, cdev_priv) dev_ddtr =
 1430         TAILQ_HEAD_INITIALIZER(dev_ddtr);
 1431 static struct task dev_dtr_task = TASK_INITIALIZER(0, destroy_dev_tq, NULL);
 1432 
 1433 static void
 1434 destroy_dev_tq(void *ctx, int pending)
 1435 {
 1436         struct cdev_priv *cp;
 1437         struct cdev *dev;
 1438         void (*cb)(void *);
 1439         void *cb_arg;
 1440 
 1441         dev_lock();
 1442         while (!TAILQ_EMPTY(&dev_ddtr)) {
 1443                 cp = TAILQ_FIRST(&dev_ddtr);
 1444                 dev = &cp->cdp_c;
 1445                 KASSERT(cp->cdp_flags & CDP_SCHED_DTR,
 1446                     ("cdev %p in dev_destroy_tq without CDP_SCHED_DTR", cp));
 1447                 TAILQ_REMOVE(&dev_ddtr, cp, cdp_dtr_list);
 1448                 cb = cp->cdp_dtr_cb;
 1449                 cb_arg = cp->cdp_dtr_cb_arg;
 1450                 destroy_devl(dev);
 1451                 dev_unlock_and_free();
 1452                 dev_rel(dev);
 1453                 if (cb != NULL)
 1454                         cb(cb_arg);
 1455                 dev_lock();
 1456         }
 1457         dev_unlock();
 1458 }
 1459 
 1460 /*
 1461  * devmtx shall be locked on entry. devmtx will be unlocked after
 1462  * function return.
 1463  */
 1464 static int
 1465 destroy_dev_sched_cbl(struct cdev *dev, void (*cb)(void *), void *arg)
 1466 {
 1467         struct cdev_priv *cp;
 1468 
 1469         dev_lock_assert_locked();
 1470         cp = cdev2priv(dev);
 1471         if (cp->cdp_flags & CDP_SCHED_DTR) {
 1472                 dev_unlock();
 1473                 return (0);
 1474         }
 1475         dev_refl(dev);
 1476         cp->cdp_flags |= CDP_SCHED_DTR;
 1477         cp->cdp_dtr_cb = cb;
 1478         cp->cdp_dtr_cb_arg = arg;
 1479         TAILQ_INSERT_TAIL(&dev_ddtr, cp, cdp_dtr_list);
 1480         dev_unlock();
 1481         taskqueue_enqueue(taskqueue_swi_giant, &dev_dtr_task);
 1482         return (1);
 1483 }
 1484 
 1485 int
 1486 destroy_dev_sched_cb(struct cdev *dev, void (*cb)(void *), void *arg)
 1487 {
 1488 
 1489         dev_lock();
 1490         return (destroy_dev_sched_cbl(dev, cb, arg));
 1491 }
 1492 
 1493 int
 1494 destroy_dev_sched(struct cdev *dev)
 1495 {
 1496 
 1497         return (destroy_dev_sched_cb(dev, NULL, NULL));
 1498 }
 1499 
 1500 void
 1501 destroy_dev_drain(struct cdevsw *csw)
 1502 {
 1503 
 1504         dev_lock();
 1505         while (!LIST_EMPTY(&csw->d_devs)) {
 1506                 msleep(&csw->d_devs, &devmtx, PRIBIO, "devscd", hz/10);
 1507         }
 1508         dev_unlock();
 1509 }
 1510 
 1511 void
 1512 drain_dev_clone_events(void)
 1513 {
 1514 
 1515         sx_xlock(&clone_drain_lock);
 1516         sx_xunlock(&clone_drain_lock);
 1517 }
 1518 
 1519 #include "opt_ddb.h"
 1520 #ifdef DDB
 1521 #include <sys/kernel.h>
 1522 
 1523 #include <ddb/ddb.h>
 1524 
 1525 DB_SHOW_COMMAND(cdev, db_show_cdev)
 1526 {
 1527         struct cdev_priv *cdp;
 1528         struct cdev *dev;
 1529         u_int flags;
 1530         char buf[512];
 1531 
 1532         if (!have_addr) {
 1533                 TAILQ_FOREACH(cdp, &cdevp_list, cdp_list) {
 1534                         dev = &cdp->cdp_c;
 1535                         db_printf("%s %p\n", dev->si_name, dev);
 1536                         if (db_pager_quit)
 1537                                 break;
 1538                 }
 1539                 return;
 1540         }
 1541 
 1542         dev = (struct cdev *)addr;
 1543         cdp = cdev2priv(dev);
 1544         db_printf("dev %s ref %d use %ld thr %ld inuse %u fdpriv %p\n",
 1545             dev->si_name, dev->si_refcount, dev->si_usecount,
 1546             dev->si_threadcount, cdp->cdp_inuse, cdp->cdp_fdpriv.lh_first);
 1547         db_printf("devsw %p si_drv0 %d si_drv1 %p si_drv2 %p\n",
 1548             dev->si_devsw, dev->si_drv0, dev->si_drv1, dev->si_drv2);
 1549         flags = dev->si_flags;
 1550 #define SI_FLAG(flag)   do {                                            \
 1551         if (flags & (flag)) {                                           \
 1552                 if (buf[0] != '\0')                                     \
 1553                         strlcat(buf, ", ", sizeof(buf));                \
 1554                 strlcat(buf, (#flag) + 3, sizeof(buf));                 \
 1555                 flags &= ~(flag);                                       \
 1556         }                                                               \
 1557 } while (0)
 1558         buf[0] = '\0';
 1559         SI_FLAG(SI_ETERNAL);
 1560         SI_FLAG(SI_ALIAS);
 1561         SI_FLAG(SI_NAMED);
 1562         SI_FLAG(SI_CHILD);
 1563         SI_FLAG(SI_DUMPDEV);
 1564         SI_FLAG(SI_CLONELIST);
 1565         db_printf("si_flags %s\n", buf);
 1566 
 1567         flags = cdp->cdp_flags;
 1568 #define CDP_FLAG(flag)  do {                                            \
 1569         if (flags & (flag)) {                                           \
 1570                 if (buf[0] != '\0')                                     \
 1571                         strlcat(buf, ", ", sizeof(buf));                \
 1572                 strlcat(buf, (#flag) + 4, sizeof(buf));                 \
 1573                 flags &= ~(flag);                                       \
 1574         }                                                               \
 1575 } while (0)
 1576         buf[0] = '\0';
 1577         CDP_FLAG(CDP_ACTIVE);
 1578         CDP_FLAG(CDP_SCHED_DTR);
 1579         db_printf("cdp_flags %s\n", buf);
 1580 }
 1581 #endif

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