The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]

FreeBSD/Linux Kernel Cross Reference
sys/dev/raid/vinum/vinumlock.c

Version: -  FREEBSD  -  FREEBSD-13-STABLE  -  FREEBSD-13-0  -  FREEBSD-12-STABLE  -  FREEBSD-12-0  -  FREEBSD-11-STABLE  -  FREEBSD-11-0  -  FREEBSD-10-STABLE  -  FREEBSD-10-0  -  FREEBSD-9-STABLE  -  FREEBSD-9-0  -  FREEBSD-8-STABLE  -  FREEBSD-8-0  -  FREEBSD-7-STABLE  -  FREEBSD-7-0  -  FREEBSD-6-STABLE  -  FREEBSD-6-0  -  FREEBSD-5-STABLE  -  FREEBSD-5-0  -  FREEBSD-4-STABLE  -  FREEBSD-3-STABLE  -  FREEBSD22  -  l41  -  OPENBSD  -  linux-2.6  -  MK84  -  PLAN9  -  xnu-8792 
SearchContext: -  none  -  3  -  10 

    1 /*-
    2  * Copyright (c) 1997, 1998
    3  *      Nan Yang Computer Services Limited.  All rights reserved.
    4  *
    5  *  Parts copyright (c) 1997, 1998 Cybernet Corporation, NetMAX project.
    6  *
    7  *  Written by Greg Lehey
    8  *
    9  *  This software is distributed under the so-called ``Berkeley
   10  *  License'':
   11  *
   12  * Redistribution and use in source and binary forms, with or without
   13  * modification, are permitted provided that the following conditions
   14  * are met:
   15  * 1. Redistributions of source code must retain the above copyright
   16  *    notice, this list of conditions and the following disclaimer.
   17  * 2. Redistributions in binary form must reproduce the above copyright
   18  *    notice, this list of conditions and the following disclaimer in the
   19  *    documentation and/or other materials provided with the distribution.
   20  * 3. All advertising materials mentioning features or use of this software
   21  *    must display the following acknowledgement:
   22  *      This product includes software developed by Nan Yang Computer
   23  *      Services Limited.
   24  * 4. Neither the name of the Company nor the names of its contributors
   25  *    may be used to endorse or promote products derived from this software
   26  *    without specific prior written permission.
   27  *
   28  * This software is provided ``as is'', and any express or implied
   29  * warranties, including, but not limited to, the implied warranties of
   30  * merchantability and fitness for a particular purpose are disclaimed.
   31  * In no event shall the company or contributors be liable for any
   32  * direct, indirect, incidental, special, exemplary, or consequential
   33  * damages (including, but not limited to, procurement of substitute
   34  * goods or services; loss of use, data, or profits; or business
   35  * interruption) however caused and on any theory of liability, whether
   36  * in contract, strict liability, or tort (including negligence or
   37  * otherwise) arising in any way out of the use of this software, even if
   38  * advised of the possibility of such damage.
   39  *
   40  * $Id: vinumlock.c,v 1.13 2000/05/02 23:25:02 grog Exp grog $
   41  * $FreeBSD: src/sys/dev/vinum/vinumlock.c,v 1.18.2.3 2001/04/04 06:27:11 grog Exp $
   42  */
   43 
   44 #include "vinumhdr.h"
   45 #include "request.h"
   46 
   47 /* Lock a drive, wait if it's in use */
   48 #if VINUMDEBUG
   49 int
   50 lockdrive(struct drive *drive, char *file, int line)
   51 #else
   52 int
   53 lockdrive(struct drive *drive)
   54 #endif
   55 {
   56     int error;
   57 
   58     /* XXX get rid of     drive->flags |= VF_LOCKING; */
   59     if ((drive->flags & VF_LOCKED)                          /* it's locked */
   60     &&(drive->pid == curproc->p_pid)) {                     /* by us! */
   61 #ifdef VINUMDEBUG
   62         log(LOG_WARNING,
   63             "vinum lockdrive: already locking %s from %s:%d, called from %s:%d\n",
   64             drive->label.name,
   65             drive->lockfilename,
   66             drive->lockline,
   67             basename(file),
   68             line);
   69 #else
   70         log(LOG_WARNING,
   71             "vinum lockdrive: already locking %s\n",
   72             drive->label.name);
   73 #endif
   74         return 0;
   75     }
   76     while ((drive->flags & VF_LOCKED) != 0) {
   77         /*
   78          * There are problems sleeping on a unique identifier,
   79          * since the drive structure can move, and the unlock
   80          * function can be called after killing the drive.
   81          * Solve this by waiting on this function; the number
   82          * of conflicts is negligible.
   83          */
   84         if ((error = tsleep(&lockdrive, 0, "vindrv", 0)) != 0)
   85             return error;
   86     }
   87     drive->flags |= VF_LOCKED;
   88     drive->pid = curproc->p_pid;                            /* it's a panic error if curproc is null */
   89 #ifdef VINUMDEBUG
   90     bcopy(basename(file), drive->lockfilename, 15);
   91     drive->lockfilename[15] = '\0';                         /* truncate if necessary */
   92     drive->lockline = line;
   93 #endif
   94     return 0;
   95 }
   96 
   97 /* Unlock a drive and let the next one at it */
   98 void
   99 unlockdrive(struct drive *drive)
  100 {
  101     drive->flags &= ~VF_LOCKED;
  102     /* we don't reset pid: it's of hysterical interest */
  103     wakeup(&lockdrive);
  104 }
  105 
  106 /* Lock a stripe of a plex, wait if it's in use */
  107 struct rangelock *
  108 lockrange(vinum_off_t stripe, struct buf *bp, struct plex *plex)
  109 {
  110     struct rangelock *lock;
  111     struct rangelock *pos;                                  /* position of first free lock */
  112     int foundlocks;                                         /* number of locks found */
  113 
  114     /*
  115      * We could get by without counting the number
  116      * of locks we find, but we have a linear search
  117      * through a table which in most cases will be
  118      * empty.  It's faster to stop when we've found
  119      * all the locks that are there.  This is also
  120      * the reason why we put pos at the beginning
  121      * instead of the end, though it requires an
  122      * extra test.
  123      */
  124     pos = NULL;
  125     foundlocks = 0;
  126 
  127     /*
  128      * we can't use 0 as a valid address, so
  129      * increment all addresses by 1.
  130      */
  131     stripe++;
  132     /*
  133      * We give the locks back from an interrupt
  134      * context, so we need to raise the spl here.
  135      */
  136     crit_enter();
  137 
  138     /* Wait here if the table is full */
  139     while (plex->usedlocks == PLEX_LOCKS)                   /* all in use */
  140         tsleep(&plex->usedlocks, 0, "vlock", 0);
  141 
  142 #ifdef DIAGNOSTIC
  143     if (plex->usedlocks >= PLEX_LOCKS)
  144         panic("lockrange: Too many locks in use");
  145 #endif
  146 
  147     lock = plex->lock;                                      /* pointer in lock table */
  148     if (plex->usedlocks > 0)                                /* something locked, */
  149         /* Search the lock table for our stripe */
  150         for (; lock < &plex->lock[PLEX_LOCKS]
  151             && foundlocks < plex->usedlocks;
  152             lock++) {
  153             if (lock->stripe) {                             /* in use */
  154                 foundlocks++;                               /* found another one in use */
  155                 if ((lock->stripe == stripe)                /* it's our stripe */
  156                 &&(lock->bp != bp)) {                       /* but not our request */
  157 #ifdef VINUMDEBUG
  158                     if (debug & DEBUG_LASTREQS) {
  159                         struct rangelock info;
  160 
  161                         info.stripe = stripe;
  162                         info.bp = bp;
  163                         logrq(loginfo_lockwait, (union rqinfou) &info, &bp->b_bio1);
  164                     }
  165 #endif
  166                     plex->lockwaits++;                      /* waited one more time */
  167                     tsleep(lock, 0, "vrlock", 0);
  168                     lock = &plex->lock[-1];                 /* start again */
  169                     foundlocks = 0;
  170                     pos = NULL;
  171                 }
  172             } else if (pos == NULL)                         /* still looking for somewhere? */
  173                 pos = lock;                                 /* a place to put this one */
  174         }
  175     /*
  176      * This untidy looking code ensures that we'll
  177      * always end up pointing to the first free lock
  178      * entry, thus minimizing the number of
  179      * iterations necessary.
  180      */
  181     if (pos == NULL)                                        /* didn't find one on the way, */
  182         pos = lock;                                         /* use the one we're pointing to */
  183 
  184     /*
  185      * The address range is free, and we're pointing
  186      * to the first unused entry.  Make it ours.
  187      */
  188     pos->stripe = stripe;
  189     pos->bp = bp;
  190     plex->usedlocks++;                                      /* one more lock */
  191     crit_exit();
  192 #ifdef VINUMDEBUG
  193     if (debug & DEBUG_LASTREQS)
  194         logrq(loginfo_lock, (union rqinfou) pos, &bp->b_bio1);
  195 #endif
  196     return pos;
  197 }
  198 
  199 /* Unlock a volume and let the next one at it */
  200 void
  201 unlockrange(int plexno, struct rangelock *lock)
  202 {
  203     struct plex *plex;
  204 
  205     plex = &PLEX[plexno];
  206 #ifdef DIAGNOSTIC
  207     if (lock < &plex->lock[0] || lock >= &plex->lock[PLEX_LOCKS])
  208         panic("vinum: rangelock %p on plex %d invalid, not between %p and %p",
  209             lock,
  210             plexno,
  211             &plex->lock[0],
  212             &plex->lock[PLEX_LOCKS]);
  213 #endif
  214 #ifdef VINUMDEBUG
  215     if (debug & DEBUG_LASTREQS)
  216         logrq(loginfo_unlock, (union rqinfou) lock, &lock->bp->b_bio1);
  217 #endif
  218     lock->stripe = 0;                                       /* no longer used */
  219     plex->usedlocks--;                                      /* one less lock */
  220     if (plex->usedlocks == PLEX_LOCKS - 1)                  /* we were full, */
  221         wakeup(&plex->usedlocks);                           /* get a waiter if one's there */
  222     wakeup((void *) lock);
  223 }
  224 
  225 /* Get a lock for the global config, wait if it's not available */
  226 int
  227 lock_config(void)
  228 {
  229     int error;
  230 
  231     while ((vinum_conf.flags & VF_LOCKED) != 0) {
  232         vinum_conf.flags |= VF_LOCKING;
  233         if ((error = tsleep(&vinum_conf, 0, "vincfg", 0)) != 0)
  234             return error;
  235     }
  236     vinum_conf.flags |= VF_LOCKED;
  237     return 0;
  238 }
  239 
  240 /* Unlock and wake up any waiters  */
  241 void
  242 unlock_config(void)
  243 {
  244     vinum_conf.flags &= ~VF_LOCKED;
  245     if ((vinum_conf.flags & VF_LOCKING) != 0) {
  246         vinum_conf.flags &= ~VF_LOCKING;
  247         wakeup(&vinum_conf);
  248     }
  249 }

Cache object: e0d20cd29b24cbb3fd246d2bd48f6aac


[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]


This page is part of the FreeBSD/Linux Linux Kernel Cross-Reference, and was automatically generated using a modified version of the LXR engine.