180 lines
5.1 KiB
C
180 lines
5.1 KiB
C
/*-
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* Copyright (c) 1997, 1998
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* Nan Yang Computer Services Limited. All rights reserved.
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*
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* This software is distributed under the so-called ``Berkeley
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* License'':
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by Nan Yang Computer
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* Services Limited.
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* 4. Neither the name of the Company nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* This software is provided ``as is'', and any express or implied
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* warranties, including, but not limited to, the implied warranties of
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* merchantability and fitness for a particular purpose are disclaimed.
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* In no event shall the company or contributors be liable for any
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* direct, indirect, incidental, special, exemplary, or consequential
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* damages (including, but not limited to, procurement of substitute
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* goods or services; loss of use, data, or profits; or business
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* interruption) however caused and on any theory of liability, whether
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* in contract, strict liability, or tort (including negligence or
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* otherwise) arising in any way out of the use of this software, even if
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* advised of the possibility of such damage.
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*
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* $Id: vinumlock.c,v 1.8 1999/01/14 02:52:13 grog Exp grog $
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*/
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#define REALLYKERNEL
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#include "opt_vinum.h"
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#include <dev/vinum/vinumhdr.h>
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/*
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* Lock routines. Currently, we lock either an individual volume
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* or the global configuration. I don't think tsleep and
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* wakeup are SMP safe. FIXME XXX
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*/
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/* Lock a drive, wait if it's in use */
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int
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lockdrive(struct drive *drive)
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{
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int error;
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/* XXX get rid of drive->flags |= VF_LOCKING; */
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while ((drive->flags & VF_LOCKED) != 0) {
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/*
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* There are problems sleeping on a unique identifier,
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* since the drive structure can move, and the unlock
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* function can be called after killing the drive.
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* Solve this by waiting on this function; the number
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* of conflicts is negligible
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*/
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if ((error = tsleep(&lockdrive,
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PRIBIO | PCATCH,
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"vindrv",
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0)) != 0)
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return error;
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}
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drive->flags |= VF_LOCKED;
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drive->pid = curproc->p_pid; /* it's a panic error if curproc is null */
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return 0;
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}
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/* Unlock a drive and let the next one at it */
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void
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unlockdrive(struct drive *drive)
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{
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drive->flags &= ~VF_LOCKED;
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/* we don't reset pid: it's of hysterical interest */
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wakeup(&lockdrive);
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}
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/* Lock a volume, wait if it's in use */
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int
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lockvol(struct volume *vol)
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{
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int error;
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while ((vol->flags & VF_LOCKED) != 0) {
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vol->flags |= VF_LOCKING;
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/*
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* It would seem to make more sense to sleep on
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* the address 'vol'. Unfortuntaly we can't
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* guarantee that this address won't change due to
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* table expansion. The address we choose won't change.
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*/
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if ((error = tsleep(&vinum_conf.volume + vol->devno,
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PRIBIO | PCATCH,
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"volock",
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0)) != 0)
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return error;
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}
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vol->flags |= VF_LOCKED;
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return 0;
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}
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/* Unlock a volume and let the next one at it */
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void
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unlockvol(struct volume *vol)
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{
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vol->flags &= ~VF_LOCKED;
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if ((vol->flags & VF_LOCKING) != 0) {
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vol->flags &= ~VF_LOCKING;
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wakeup(&vinum_conf.volume + vol->devno);
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}
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}
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/* Lock a plex, wait if it's in use */
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int
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lockplex(struct plex *plex)
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{
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int error;
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while ((plex->flags & VF_LOCKED) != 0) {
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plex->flags |= VF_LOCKING;
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/*
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* It would seem to make more sense to sleep on
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* the address 'plex'. Unfortunately we can't
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* guarantee that this address won't change due to
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* table expansion. The address we choose won't change.
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*/
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if ((error = tsleep(&vinum_conf.plex + plex->sdnos[0],
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PRIBIO | PCATCH,
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"plexlk",
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0)) != 0)
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return error;
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}
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plex->flags |= VF_LOCKED;
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return 0;
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}
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/* Unlock a plex and let the next one at it */
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void
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unlockplex(struct plex *plex)
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{
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plex->flags &= ~VF_LOCKED;
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if ((plex->flags & VF_LOCKING) != 0) {
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plex->flags &= ~VF_LOCKING;
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wakeup(&vinum_conf.plex + plex->plexno);
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}
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}
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/* Get a lock for the global config, wait if it's not available */
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int
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lock_config(void)
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{
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int error;
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while ((vinum_conf.flags & VF_LOCKED) != 0) {
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vinum_conf.flags |= VF_LOCKING;
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if ((error = tsleep(&vinum_conf, PRIBIO | PCATCH, "vincfg", 0)) != 0)
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return error;
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}
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vinum_conf.flags |= VF_LOCKED;
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return 0;
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}
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/* Unlock and wake up any waiters */
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void
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unlock_config(void)
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{
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vinum_conf.flags &= ~VF_LOCKED;
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if ((vinum_conf.flags & VF_LOCKING) != 0) {
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vinum_conf.flags &= ~VF_LOCKING;
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wakeup(&vinum_conf);
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}
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}
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