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Diffstat (limited to 'include/linux/idr.h')
-rw-r--r--include/linux/idr.h25
1 files changed, 24 insertions, 1 deletions
diff --git a/include/linux/idr.h b/include/linux/idr.h
index 7b1c5c6f9a06..a6f38b5c34e4 100644
--- a/include/linux/idr.h
+++ b/include/linux/idr.h
@@ -37,6 +37,7 @@ struct idr_layer {
};
struct idr {
+ struct idr_layer __rcu *hint; /* the last layer allocated from */
struct idr_layer __rcu *top;
struct idr_layer *id_free;
int layers; /* only valid w/o concurrent changes */
@@ -71,7 +72,7 @@ struct idr {
* This is what we export.
*/
-void *idr_find(struct idr *idp, int id);
+void *idr_find_slowpath(struct idr *idp, int id);
int idr_pre_get(struct idr *idp, gfp_t gfp_mask);
int idr_get_new_above(struct idr *idp, void *ptr, int starting_id, int *id);
void idr_preload(gfp_t gfp_mask);
@@ -97,6 +98,28 @@ static inline void idr_preload_end(void)
}
/**
+ * idr_find - return pointer for given id
+ * @idp: idr handle
+ * @id: lookup key
+ *
+ * Return the pointer given the id it has been registered with. A %NULL
+ * return indicates that @id is not valid or you passed %NULL in
+ * idr_get_new().
+ *
+ * This function can be called under rcu_read_lock(), given that the leaf
+ * pointers lifetimes are correctly managed.
+ */
+static inline void *idr_find(struct idr *idr, int id)
+{
+ struct idr_layer *hint = rcu_dereference_raw(idr->hint);
+
+ if (hint && (id & ~IDR_MASK) == hint->prefix)
+ return rcu_dereference_raw(hint->ary[id & IDR_MASK]);
+
+ return idr_find_slowpath(idr, id);
+}
+
+/**
* idr_get_new - allocate new idr entry
* @idp: idr handle
* @ptr: pointer you want associated with the id