Re: [PATCH v8 1/5 alt] rust: add generic static_key_false

---
This is an alternate version of patch 1 that resolves the conflict with
https://lore.kernel.org/all/20240725183325.122827-7-ojeda@kernel.org/ (local)

 rust/bindings/bindings_helper.h |  1 +
 rust/helpers/helpers.c          |  1 +
 rust/helpers/tracepoint.c       | 18 ++++++++++++++++++
 rust/kernel/jump_label.rs       | 29 +++++++++++++++++++++++++++++
 rust/kernel/lib.rs              |  1 +
 5 files changed, 50 insertions(+)
 create mode 100644 rust/helpers/tracepoint.c
 create mode 100644 rust/kernel/jump_label.rs

diff --git a/rust/bindings/bindings_helper.h b/rust/bindings/bindings_helper.h
index ae82e9c941af..e0846e7e93e6 100644
--- a/rust/bindings/bindings_helper.h
+++ b/rust/bindings/bindings_helper.h

@@ -14,6 +14,7 @@
 #include <linux/ethtool.h>
 #include <linux/firmware.h>
 #include <linux/jiffies.h>
+#include <linux/jump_label.h>
 #include <linux/mdio.h>
 #include <linux/phy.h>
 #include <linux/refcount.h>

diff --git a/rust/helpers/helpers.c b/rust/helpers/helpers.c
index 173533616c91..5b17839de43a 100644
--- a/rust/helpers/helpers.c
+++ b/rust/helpers/helpers.c

@@ -20,6 +20,7 @@
 #include "slab.c"
 #include "spinlock.c"
 #include "task.c"
+#include "tracepoint.c"
 #include "uaccess.c"
 #include "wait.c"
 #include "workqueue.c"

diff --git a/rust/helpers/tracepoint.c b/rust/helpers/tracepoint.c
new file mode 100644
index 000000000000..02aafb2b226f
--- /dev/null
+++ b/rust/helpers/tracepoint.c

@@ -0,0 +1,18 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * Helpers for tracepoints. At the moment, helpers are only needed when
+ * CONFIG_JUMP_LABEL is disabled, as `static_key_count` is only marked inline
+ * in that case.
+ *
+ * Copyright (C) 2024 Google LLC.
+ */
+
+#include <linux/jump_label.h>
+
+#ifndef CONFIG_JUMP_LABEL
+int rust_helper_static_key_count(struct static_key *key)
+{
+	return static_key_count(key);
+}
+#endif

diff --git a/rust/kernel/jump_label.rs b/rust/kernel/jump_label.rs
new file mode 100644
index 000000000000..011e1fc1d19a
--- /dev/null
+++ b/rust/kernel/jump_label.rs

@@ -0,0 +1,29 @@
+// SPDX-License-Identifier: GPL-2.0
+
+// Copyright (C) 2024 Google LLC.
+
+//! Logic for static keys.
+//!
+//! C header: [`include/linux/jump_label.h`](srctree/include/linux/jump_label.h).
+
+/// Branch based on a static key.
+///
+/// Takes three arguments:
+///
+/// * `key` - the path to the static variable containing the `static_key`.
+/// * `keytyp` - the type of `key`.
+/// * `field` - the name of the field of `key` that contains the `static_key`.
+///
+/// # Safety
+///
+/// The macro must be used with a real static key defined by C.
+#[macro_export]
+macro_rules! static_key_false {
+    ($key:path, $keytyp:ty, $field:ident) => {{
+        let _key: *const $keytyp = ::core::ptr::addr_of!($key);
+        let _key: *const $crate::bindings::static_key = ::core::ptr::addr_of!((*_key).$field);
+
+        $crate::bindings::static_key_count(_key.cast_mut()) > 0
+    }};
+}
+pub use static_key_false;

diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs
index 274bdc1b0a82..91af9f75d121 100644
--- a/rust/kernel/lib.rs
+++ b/rust/kernel/lib.rs

@@ -36,6 +36,7 @@
 pub mod firmware;
 pub mod init;
 pub mod ioctl;
+pub mod jump_label;
 #[cfg(CONFIG_KUNIT)]
 pub mod kunit;
 #[cfg(CONFIG_NET)]

-- 
2.46.0.184.g6999bdac58-goog