On Tue, Nov 22, 2022 at 06:55:30PM +0000, Dmitry Safonov wrote:

key->enabled is indeed a ref-counter as it's documented in multiple
places: top comment in jump_label.h, Documentation/staging/static-keys.rst,
etc.

+/***
+ * static_key_fast_inc_not_negative - adds a user for a static key
+ * @key: static key that must be already enabled
+ *
+ * The caller must make sure that the static key can't get disabled while
+ * in this function. It doesn't patch jump labels, only adds a user to
+ * an already enabled static key.
+ *
+ * Returns true if the increment was done.
+ */

One more thing; it might be useful to point out that unlike refcount_t
this thing does not saturate but will fail to increment on overflow.