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lib: add idr_remove_all 

Remove all ids from the given idr tree.  idr_destroy() only frees up
unused, cached idp_layers, but this function will remove all id mappings
and leave all idp_layers unused.

A typical clean-up sequence for objects stored in an idr tree, will use
idr_for_each() to free all objects, if necessay, then idr_remove_all() to
remove all ids, and idr_destroy() to free up the cached idr_layers.

Signed-off-by: Kristian Hoegsberg <krh@redhat.com>
Cc: Tejun Heo <htejun@gmail.com>
Cc: Dave Airlie <airlied@linux.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Kristian Hoegsberg 2007-07-15 23:37:24 -07:00 committed by Linus Torvalds
parent 96d7fa421e
commit 23936cc0b5
2 changed files with 48 additions and 0 deletions
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1
include/linux/idr.h
View File

@ -82,6 +82,7 @@ int idr_for_each(struct idr *idp,
int (*fn)(int id, void *p, void *data), void *data);
void *idr_replace(struct idr *idp, void *ptr, int id);
void idr_remove(struct idr *idp, int id);
void idr_remove_all(struct idr *idp);
void idr_destroy(struct idr *idp);
void idr_init(struct idr *idp);

47
lib/idr.c
View File

@ -390,6 +390,53 @@ void idr_remove(struct idr *idp, int id)
}
EXPORT_SYMBOL(idr_remove);
/**
* idr_remove_all - remove all ids from the given idr tree
* @idp: idr handle
*
* idr_destroy() only frees up unused, cached idp_layers, but this
* function will remove all id mappings and leave all idp_layers
* unused.
*
* A typical clean-up sequence for objects stored in an idr tree, will
* use idr_for_each() to free all objects, if necessay, then
* idr_remove_all() to remove all ids, and idr_destroy() to free
* up the cached idr_layers.
*/
void idr_remove_all(struct idr *idp)
{
int n, id, max, error = 0;
struct idr_layer *p;
struct idr_layer *pa[MAX_LEVEL];
struct idr_layer **paa = &pa[0];
n = idp->layers * IDR_BITS;
p = idp->top;
max = 1 << n;
id = 0;
while (id < max && !error) {
while (n > IDR_BITS && p) {
n -= IDR_BITS;
*paa++ = p;
p = p->ary[(id >> n) & IDR_MASK];
}
id += 1 << n;
while (n < fls(id)) {
if (p) {
memset(p, 0, sizeof *p);
free_layer(idp, p);
}
n += IDR_BITS;
p = *--paa;
}
}
idp->top = NULL;
idp->layers = 0;
}
EXPORT_SYMBOL(idr_remove_all);
/**
* idr_destroy - release all cached layers within an idr tree
* idp: idr handle