idr: document exit conditions on idr_for_each_entry better
And some manual common subexpression elimination which may help the
compiler produce smaller code.
Signed-off-by: George Spelvin <linux@horizon.com>
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/include/linux/idr.h b/include/linux/idr.h
index 2640c7e..6ece058 100644
--- a/include/linux/idr.h
+++ b/include/linux/idr.h
@@ -122,11 +122,13 @@
* @idp: idr handle
* @entry: the type * to use as cursor
* @id: id entry's key
+ *
+ * @entry and @id do not need to be initialized before the loop, and
+ * after normal terminatinon @entry is left with the value NULL. This
+ * is convenient for a "not found" value.
*/
-#define idr_for_each_entry(idp, entry, id) \
- for (id = 0, entry = (typeof(entry))idr_get_next((idp), &(id)); \
- entry != NULL; \
- ++id, entry = (typeof(entry))idr_get_next((idp), &(id)))
+#define idr_for_each_entry(idp, entry, id) \
+ for (id = 0; ((entry) = idr_get_next(idp, &(id))) != NULL; ++id)
/*
* Don't use the following functions. These exist only to suppress