[PATCH 14/17] ratelimit: assert static storage for DEFINE_RATELIMIT_STATE()

[Yury Norov]

DEFINE_RATELIMIT_STATE() uses a static raw spinlock initializer, which
requires a persistent object address for lockdep. Automatic objects must
use ratelimit_state_init().

Add ASSERT_STATIC_STORAGE() to the declaration and align the virtio tools
stub. The virtio tools use a private compiler.h, so provide the same
assertion helper and its unused attribute there as well.

Assisted-by: OpenAI Codex
Signed-off-by: Yury Norov <ynorov@xxxxxxxxxx>
---
 include/linux/ratelimit_types.h | 4 +++-
 tools/virtio/linux/compiler.h   | 9 +++++++++
 tools/virtio/linux/ratelimit.h  | 6 +++++-
 3 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/include/linux/ratelimit_types.h b/include/linux/ratelimit_types.h
index b19c4354540a..977fdfff5926 100644
--- a/include/linux/ratelimit_types.h
+++ b/include/linux/ratelimit_types.h
@@ -2,6 +2,7 @@
 #ifndef _LINUX_RATELIMIT_TYPES_H
 #define _LINUX_RATELIMIT_TYPES_H
 
+#include <linux/compiler.h>
 #include <linux/bits.h>
 #include <linux/param.h>
 #include <linux/spinlock_types_raw.h>
@@ -40,7 +41,8 @@ struct ratelimit_state {
 #define DEFINE_RATELIMIT_STATE(name, interval_init, burst_init)		\
 									\
 	struct ratelimit_state name =					\
-		RATELIMIT_STATE_INIT(name, interval_init, burst_init)	\
+		RATELIMIT_STATE_INIT(name, interval_init, burst_init);	\
+	ASSERT_STATIC_STORAGE(name)
 
 extern int ___ratelimit(struct ratelimit_state *rs, const char *func);
 #define __ratelimit(state) ___ratelimit(state, __func__)
diff --git a/tools/virtio/linux/compiler.h b/tools/virtio/linux/compiler.h
index 0f25db473f55..3c1eca4a4380 100644
--- a/tools/virtio/linux/compiler.h
+++ b/tools/virtio/linux/compiler.h
@@ -15,6 +15,15 @@
 
 #define __aligned(x) __attribute((__aligned__(x)))
 
+#ifndef __always_unused
+#define __always_unused __attribute__((__unused__))
+#endif
+
+/* Enforce static storage duration. */
+#define ASSERT_STATIC_STORAGE(name) \
+	static typeof(name) * const __always_unused \
+		name##_storage_check = &(name)
+
 /**
  * data_race - mark an expression as containing intentional data races
  *
diff --git a/tools/virtio/linux/ratelimit.h b/tools/virtio/linux/ratelimit.h
index dcce1725f90d..c15c82a5ca21 100644
--- a/tools/virtio/linux/ratelimit.h
+++ b/tools/virtio/linux/ratelimit.h
@@ -1,4 +1,8 @@
-#define DEFINE_RATELIMIT_STATE(name, interval_init, burst_init)	int name = 0
+#include <linux/compiler.h>
+
+#define DEFINE_RATELIMIT_STATE(name, interval_init, burst_init) \
+	int name = 0;						\
+	ASSERT_STATIC_STORAGE(name)
 
 #define __ratelimit(x) (*(x))
 
-- 
2.53.0