+EXPORT_SYMBOL(idr_preload);
+
+/**
+ * idr_alloc - allocate new idr entry
+ * @idr: the (initialized) idr
+ * @ptr: pointer to be associated with the new id
+ * @start: the minimum id (inclusive)
+ * @end: the maximum id (exclusive, <= 0 for max)
+ * @gfp_mask: memory allocation flags
+ *
+ * Allocate an id in [start, end) and associate it with @ptr. If no ID is
+ * available in the specified range, returns -ENOSPC. On memory allocation
+ * failure, returns -ENOMEM.
+ *
+ * Note that @end is treated as max when <= 0. This is to always allow
+ * using @start + N as @end as long as N is inside integer range.
+ *
+ * The user is responsible for exclusively synchronizing all operations
+ * which may modify @idr. However, read-only accesses such as idr_find()
+ * or iteration can be performed under RCU read lock provided the user
+ * destroys @ptr in RCU-safe way after removal from idr.
+ */
+int idr_alloc(struct idr *idr, void *ptr, int start, int end, gfp_t gfp_mask)
+{
+ int max = end > 0 ? end - 1 : INT_MAX; /* inclusive upper limit */
+ struct idr_layer *pa[MAX_IDR_LEVEL + 1];
+ int id;
+
+ might_sleep_if(gfp_mask & __GFP_WAIT);
+
+ /* sanity checks */
+ if (WARN_ON_ONCE(start < 0))
+ return -EINVAL;
+ if (unlikely(max < start))
+ return -ENOSPC;
+
+ /* allocate id */
+ id = idr_get_empty_slot(idr, start, pa, gfp_mask, NULL);
+ if (unlikely(id < 0))
+ return id;
+ if (unlikely(id > max))
+ return -ENOSPC;
+
+ idr_fill_slot(idr, ptr, id, pa);
+ return id;
+}
+EXPORT_SYMBOL_GPL(idr_alloc);