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/*-
* Copyright (c) 1997, 1998
* Nan Yang Computer Services Limited. All rights reserved.
*
* This software is distributed under the so-called ``Berkeley
* License'':
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by Nan Yang Computer
* Services Limited.
* 4. Neither the name of the Company nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* This software is provided ``as is'', and any express or implied
* warranties, including, but not limited to, the implied warranties of
* merchantability and fitness for a particular purpose are disclaimed.
* In no event shall the company or contributors be liable for any
* direct, indirect, incidental, special, exemplary, or consequential
* damages (including, but not limited to, procurement of substitute
* goods or services; loss of use, data, or profits; or business
* interruption) however caused and on any theory of liability, whether
* in contract, strict liability, or tort (including negligence or
* otherwise) arising in any way out of the use of this software, even if
* advised of the possibility of such damage.
*
* $Id: lock.c,v 1.6 1998/07/28 06:32:57 grog Exp grog $
*/
#define REALLYKERNEL
#include "vinumhdr.h"
/* Lock routines. Currently, we lock either an individual volume
* or the global configuration. I don't think tsleep and
* wakeup are SMP safe. FIXME XXX */
/* Lock a volume, wait if it's in use */
int
lockvol(struct volume *vol)
{
int error;
while ((vol->flags & VF_LOCKED) != 0) {
vol->flags |= VF_LOCKING;
/* It would seem to make more sense to sleep on
* the address 'vol'. Unfortuntaly we can't
* guarantee that this address won't change due to
* table expansion. The address we choose won't change. */
if ((error = tsleep(&vinum_conf.volume + vol->devno,
PRIBIO | PCATCH,
"volock",
0)) != 0)
return error;
}
vol->flags |= VF_LOCKED;
return 0;
}
/* Unlock a volume and let the next one at it */
void
unlockvol(struct volume *vol)
{
vol->flags &= ~VF_LOCKED;
if ((vol->flags & VF_LOCKING) != 0) {
vol->flags &= ~VF_LOCKING;
wakeup(&vinum_conf.volume + vol->devno);
}
}
/* Lock a plex, wait if it's in use */
int
lockplex(struct plex *plex)
{
int error;
while ((plex->flags & VF_LOCKED) != 0) {
plex->flags |= VF_LOCKING;
/* It would seem to make more sense to sleep on
* the address 'plex'. Unfortuntaly we can't
* guarantee that this address won't change due to
* table expansion. The address we choose won't change. */
if ((error = tsleep(&vinum_conf.plex + plex->sdnos[0],
PRIBIO | PCATCH,
"plexlk",
0)) != 0)
return error;
}
plex->flags |= VF_LOCKED;
return 0;
}
/* Unlock a plex and let the next one at it */
void
unlockplex(struct plex *plex)
{
plex->flags &= ~VF_LOCKED;
if ((plex->flags & VF_LOCKING) != 0) {
plex->flags &= ~VF_LOCKING;
wakeup(&vinum_conf.plex + plex->plexno);
}
}
/* Get a lock for the global config, wait if it's not available */
int
lock_config(void)
{
int error;
while ((vinum_conf.flags & VF_LOCKED) != 0) {
vinum_conf.flags |= VF_LOCKING;
if ((error = tsleep(&vinum_conf, PRIBIO | PCATCH, "vincfg", 0)) != 0)
return error;
}
vinum_conf.flags |= VF_LOCKED;
return 0;
}
/* Unlock and wake up any waiters */
void
unlock_config(void)
{
vinum_conf.flags &= ~VF_LOCKED;
if ((vinum_conf.flags & VF_LOCKING) != 0) {
vinum_conf.flags &= ~VF_LOCKING;
wakeup(&vinum_conf);
}
}
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