[linux-block.git] / include / linux / once_lite.h

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_ONCE_LITE_H
#define _LINUX_ONCE_LITE_H

#include <linux/types.h>

/* Call a function once. Similar to DO_ONCE(), but does not use jump label
 * patching via static keys.
 */
#define DO_ONCE_LITE(func, ...)						\
	DO_ONCE_LITE_IF(true, func, ##__VA_ARGS__)

#define __ONCE_LITE_IF(condition)					\
	({								\
		static bool __section(".data.once") __already_done;	\
		bool __ret_cond = !!(condition);			\
		bool __ret_once = false;				\
									\
		if (unlikely(__ret_cond && !__already_done)) {		\
			__already_done = true;				\
			__ret_once = true;				\
		}							\
		unlikely(__ret_once);					\
	})

#define DO_ONCE_LITE_IF(condition, func, ...)				\
	({								\
		bool __ret_do_once = !!(condition);			\
									\
		if (__ONCE_LITE_IF(__ret_do_once))			\
			func(__VA_ARGS__);				\
									\
		unlikely(__ret_do_once);				\
	})

#endif /* _LINUX_ONCE_LITE_H */
Commit	Line	Data
a358f406 TL	1	/* SPDX-License-Identifier: GPL-2.0 */
	2	#ifndef _LINUX_ONCE_LITE_H
	3	#define _LINUX_ONCE_LITE_H
	4
	5	#include <linux/types.h>
	6
	7	/* Call a function once. Similar to DO_ONCE(), but does not use jump label
	8	* patching via static keys.
	9	*/
	10	#define DO_ONCE_LITE(func, ...) \
	11	DO_ONCE_LITE_IF(true, func, ##__VA_ARGS__)
a1a5482a PZ	12
a1a5482a PZ	13	#define __ONCE_LITE_IF(condition) \
a358f406 TL	14	({ \
a358f406 TL	15	static bool __section(".data.once") __already_done; \
a1a5482a PZ	16	bool __ret_cond = !!(condition); \
a1a5482a PZ	17	bool __ret_once = false; \
a358f406	18	\
a1a5482a	19	if (unlikely(__ret_cond && !__already_done)) { \
a358f406	20	__already_done = true; \
a1a5482a	21	__ret_once = true; \
a358f406	22	} \
a1a5482a PZ	23	unlikely(__ret_once); \
	24	})
	25
	26	#define DO_ONCE_LITE_IF(condition, func, ...) \
	27	({ \
	28	bool __ret_do_once = !!(condition); \
	29	\
	30	if (__ONCE_LITE_IF(__ret_do_once)) \
	31	func(__VA_ARGS__); \
	32	\
a358f406 TL	33	unlikely(__ret_do_once); \
	34	})
	35
	36	#endif /* _LINUX_ONCE_LITE_H */