/*
* Copyright (c) 2000-2003,2005 Silicon Graphics, Inc.
* All Rights Reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it would be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "xfs.h"
/*
* Source file used to associate/disassociate behaviors with virtualized
* objects. See xfs_behavior.h for more information about behaviors, etc.
*
* The implementation is split between functions in this file and macros
* in xfs_behavior.h.
*/
/*
* Insert a new behavior descriptor into a behavior chain.
*
* The behavior chain is ordered based on the 'position' number which
* lives in the first field of the ops vector (higher numbers first).
*
* Attempts to insert duplicate ops result in an EINVAL return code.
* Otherwise, return 0 to indicate success.
*/
int
bhv_insert(bhv_head_t *bhp, bhv_desc_t *bdp)
{
bhv_desc_t *curdesc, *prev;
int position;
/*
* Validate the position value of the new behavior.
*/
position = BHV_POSITION(bdp);
ASSERT(position >= BHV_POSITION_BASE && position <= BHV_POSITION_TOP);
/*
* Find location to insert behavior. Check for duplicates.
*/
prev = NULL;
for (curdesc = bhp->bh_first;
curdesc != NULL;
curdesc = curdesc->bd_next) {
/* Check for duplication. */
if (curdesc->bd_ops == bdp->bd_ops) {
ASSERT(0);
return EINVAL;
}
/* Find correct position */
if (position >= BHV_POSITION(curdesc)) {
ASSERT(position != BHV_POSITION(curdesc));
break; /* found it */
}
prev = curdesc;
}
if (prev == NULL) {
/* insert at front of chain */
bdp->bd_next = bhp->bh_first;
bhp->bh_first = bdp;
} else {
/* insert after prev */
bdp->bd_next = prev->bd_next;
prev->bd_next = bdp;
}
return 0;
}
/*
* Remove a behavior descriptor from a position in a behavior chain;
* the position is guaranteed not to be the first position.
* Should only be called by the bhv_remove() macro.
*/
void
bhv_remove_not_first(bhv_head_t *bhp, bhv_desc_t *bdp)
{
bhv_desc_t *curdesc, *prev;
ASSERT(bhp->bh_first != NULL);
ASSERT(bhp->bh_first->bd_next != NULL);
prev = bhp->bh_first;
for (curdesc = bhp->bh_first->bd_next;
curdesc != NULL;
curdesc = curdesc->bd_next) {
if (curdesc == bdp)
break; /* found it */
prev = curdesc;
}
ASSERT(curdesc == bdp);
prev->bd_next = bdp->bd_next; /* remove from after prev */
}
/*
* Looks for the first behavior within a specified range of positions.
* Return the associated behavior descriptor. Or NULL, if none found.
*/
bhv_desc_t *
bhv_lookup_range(bhv_head_t *bhp, int low, int high)
{
bhv_desc_t *curdesc;
for (curdesc = bhp->bh_first;
curdesc != NULL;
curdesc = curdesc->bd_next) {
int position = BHV_POSITION(curdesc);
if (position <= high) {
if (position >= low)
return curdesc;
return NULL;
}
}
return NULL;
}
/*
* Return the base behavior in the chain, or NULL if the chain
* is empty.
*
* The caller has not read locked the behavior chain, so acquire the
* lock before traversing the chain.
*/
bhv_desc_t *
bhv_base(bhv_head_t *bhp)
{
bhv_desc_t *curdesc;
for (curdesc = bhp->bh_first;
curdesc != NULL;
curdesc = curdesc->bd_next) {
if (curdesc->bd_next == NULL) {
return curdesc;
}
}
return NULL;
}
void
bhv_head_init(
bhv_head_t *bhp,
char *name)
{
bhp->bh_first = NULL;
}
void
bhv_insert_initial(
bhv_head_t *bhp,
bhv_desc_t *bdp)
{
ASSERT(bhp->bh_first == NULL);
(bhp)->bh_first = bdp;
}
void
bhv_head_destroy(
bhv_head_t *bhp)
{
ASSERT(bhp->bh_first == NULL);
}
