xref: /linux-6.15/include/linux/once_lite.h (revision dbefa1f3)
1a358f406STanner Love /* SPDX-License-Identifier: GPL-2.0 */
2a358f406STanner Love #ifndef _LINUX_ONCE_LITE_H
3a358f406STanner Love #define _LINUX_ONCE_LITE_H
4a358f406STanner Love 
5a358f406STanner Love #include <linux/types.h>
6a358f406STanner Love 
7a358f406STanner Love /* Call a function once. Similar to DO_ONCE(), but does not use jump label
8a358f406STanner Love  * patching via static keys.
9a358f406STanner Love  */
10a358f406STanner Love #define DO_ONCE_LITE(func, ...)						\
11a358f406STanner Love 	DO_ONCE_LITE_IF(true, func, ##__VA_ARGS__)
12a1a5482aSPeter Zijlstra 
13a1a5482aSPeter Zijlstra #define __ONCE_LITE_IF(condition)					\
14a358f406STanner Love 	({								\
15*dbefa1f3SMasahiro Yamada 		static bool __section(".data..once") __already_done;	\
16a1a5482aSPeter Zijlstra 		bool __ret_cond = !!(condition);			\
17a1a5482aSPeter Zijlstra 		bool __ret_once = false;				\
18a1a5482aSPeter Zijlstra 									\
19a1a5482aSPeter Zijlstra 		if (unlikely(__ret_cond && !__already_done)) {		\
20a1a5482aSPeter Zijlstra 			__already_done = true;				\
21a1a5482aSPeter Zijlstra 			__ret_once = true;				\
22a1a5482aSPeter Zijlstra 		}							\
23a1a5482aSPeter Zijlstra 		unlikely(__ret_once);					\
24a1a5482aSPeter Zijlstra 	})
25a1a5482aSPeter Zijlstra 
26a1a5482aSPeter Zijlstra #define DO_ONCE_LITE_IF(condition, func, ...)				\
27a1a5482aSPeter Zijlstra 	({								\
28a358f406STanner Love 		bool __ret_do_once = !!(condition);			\
29a358f406STanner Love 									\
30a1a5482aSPeter Zijlstra 		if (__ONCE_LITE_IF(__ret_do_once))			\
31a358f406STanner Love 			func(__VA_ARGS__);				\
32a1a5482aSPeter Zijlstra 									\
33a358f406STanner Love 		unlikely(__ret_do_once);				\
34a358f406STanner Love 	})
35a358f406STanner Love 
36a358f406STanner Love #endif /* _LINUX_ONCE_LITE_H */
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