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>
diff --git a/lib/idr.c b/lib/idr.c
index d29da61..5ca67b3 100644
--- a/lib/idr.c
+++ b/lib/idr.c
@@ -391,6 +391,53 @@
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
*/