diff options
Diffstat (limited to 'fs/xfs/xfs_behavior.c')
| -rw-r--r-- | fs/xfs/xfs_behavior.c | 218 |
1 files changed, 218 insertions, 0 deletions
diff --git a/fs/xfs/xfs_behavior.c b/fs/xfs/xfs_behavior.c new file mode 100644 index 000000000000..16088e175ecc --- /dev/null +++ b/fs/xfs/xfs_behavior.c @@ -0,0 +1,218 @@ +/* + * Copyright (c) 2000-2003 Silicon Graphics, Inc. All Rights Reserved. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of version 2 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. + * + * Further, this software is distributed without any warranty that it is + * free of the rightful claim of any third person regarding infringement + * or the like. Any license provided herein, whether implied or + * otherwise, applies only to this software file. Patent licenses, if + * any, provided herein do not apply to combinations of this program with + * other software, or any other product whatsoever. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write the Free Software Foundation, Inc., 59 + * Temple Place - Suite 330, Boston MA 02111-1307, USA. + * + * Contact information: Silicon Graphics, Inc., 1600 Amphitheatre Pkwy, + * Mountain View, CA 94043, or: + * + * http://www.sgi.com + * + * For further information regarding this notice, see: + * + * http://oss.sgi.com/projects/GenInfo/SGIGPLNoticeExplan/ + * + */ +#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). + * + * Attemps 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 postition 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 */ +} + +/* + * Look for a specific ops vector on the specified behavior chain. + * Return the associated behavior descriptor. Or NULL, if not found. + */ +bhv_desc_t * +bhv_lookup(bhv_head_t *bhp, void *ops) +{ + bhv_desc_t *curdesc; + + for (curdesc = bhp->bh_first; + curdesc != NULL; + curdesc = curdesc->bd_next) { + + if (curdesc->bd_ops == ops) + return curdesc; + } + + return NULL; +} + +/* + * 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); +} |