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-rw-r--r--lib/idr.c46
1 files changed, 46 insertions, 0 deletions
diff --git a/lib/idr.c b/lib/idr.c
index dab4bca86f5d..80ca9aca038b 100644
--- a/lib/idr.c
+++ b/lib/idr.c
@@ -579,6 +579,52 @@ int idr_for_each(struct idr *idp,
EXPORT_SYMBOL(idr_for_each);
/**
+ * idr_get_next - lookup next object of id to given id.
+ * @idp: idr handle
+ * @id: pointer to lookup key
+ *
+ * Returns pointer to registered object with id, which is next number to
+ * given id.
+ */
+
+void *idr_get_next(struct idr *idp, int *nextidp)
+{
+ struct idr_layer *p, *pa[MAX_LEVEL];
+ struct idr_layer **paa = &pa[0];
+ int id = *nextidp;
+ int n, max;
+
+ /* find first ent */
+ n = idp->layers * IDR_BITS;
+ max = 1 << n;
+ p = rcu_dereference(idp->top);
+ if (!p)
+ return NULL;
+
+ while (id < max) {
+ while (n > 0 && p) {
+ n -= IDR_BITS;
+ *paa++ = p;
+ p = rcu_dereference(p->ary[(id >> n) & IDR_MASK]);
+ }
+
+ if (p) {
+ *nextidp = id;
+ return p;
+ }
+
+ id += 1 << n;
+ while (n < fls(id)) {
+ n += IDR_BITS;
+ p = *--paa;
+ }
+ }
+ return NULL;
+}
+
+
+
+/**
* idr_replace - replace pointer for given id
* @idp: idr handle
* @ptr: pointer you want associated with the id