On Thu, Nov 20, 2025 at 03:49:04PM +0100, Marco Elver wrote:
> +/**
> + * context_guard_struct() - declare or define a context guard struct
> + * @name: struct name
> + *
> + * Helper to declare or define a struct type that is also a context guard.
> + *
> + * .. code-block:: c
> + *
> + * context_guard_struct(my_handle) {
> + * int foo;
> + * long bar;
> + * };
> + *
> + * struct some_state {
> + * ...
> + * };
> + * // ... declared elsewhere ...
> + * context_guard_struct(some_state);
> + *
> + * Note: The implementation defines several helper functions that can acquire
> + * and release the context guard.
> + */
> +# define context_guard_struct(name, ...)
> \
> + struct __ctx_guard_type(name) __VA_ARGS__ name;
> \
> + static __always_inline void __acquire_ctx_guard(const struct name *var)
> \
> + __attribute__((overloadable)) __no_context_analysis
> __acquires_ctx_guard(var) { } \
> + static __always_inline void __acquire_shared_ctx_guard(const struct
> name *var) \
> + __attribute__((overloadable)) __no_context_analysis
> __acquires_shared_ctx_guard(var) { } \
> + static __always_inline bool __try_acquire_ctx_guard(const struct name
> *var, bool ret) \
> + __attribute__((overloadable)) __no_context_analysis
> __try_acquires_ctx_guard(1, var) \
> + { return ret; }
> \
> + static __always_inline bool __try_acquire_shared_ctx_guard(const struct
> name *var, bool ret) \
> + __attribute__((overloadable)) __no_context_analysis
> __try_acquires_shared_ctx_guard(1, var) \
> + { return ret; }
> \
> + static __always_inline void __release_ctx_guard(const struct name *var)
> \
> + __attribute__((overloadable)) __no_context_analysis
> __releases_ctx_guard(var) { } \
> + static __always_inline void __release_shared_ctx_guard(const struct
> name *var) \
> + __attribute__((overloadable)) __no_context_analysis
> __releases_shared_ctx_guard(var) { } \
> + static __always_inline void __assume_ctx_guard(const struct name *var)
> \
> + __attribute__((overloadable)) __assumes_ctx_guard(var) { }
> \
> + static __always_inline void __assume_shared_ctx_guard(const struct name
> *var) \
> + __attribute__((overloadable)) __assumes_shared_ctx_guard(var) {
> } \
> + struct name
-typedef struct {
+context_guard_struct(rwlock) {
struct rwbase_rt rwbase;
atomic_t readers;
#ifdef CONFIG_DEBUG_LOCK_ALLOC
struct lockdep_map dep_map;
#endif
-} rwlock_t;
+};
+typedef struct rwlock rwlock_t;
I must say I find the 'guard' naming here somewhat confusing. This is
not a guard, but an actual lock type.
