Introduce DO_COND(), DO_ONCE() and DO_ONCE_COND(). These
macros should ease the consolidation of CPP code when
it is deemed to be executed only once and/or after a
condition is verified. This incluse printk_once, WARN_ON,
WARN_ON_ONCE, etc...
Signed-off-by: Frederic Weisbecker <fweis...@gmail.com>
Cc: Andrew Morton <a...@linux-foundation.org>
Cc: Steven Rostedt <rost...@goodmis.org>
Cc: Linus Torvalds <torva...@linux-foundation.org>
Cc: H. Peter Anvin <h...@zytor.com>
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: Thomas Gleixner <t...@linutronix.de>
Cc: Liu Chuansheng <chuansheng....@intel.com>
Cc: Ingo Molnar <mi...@kernel.org>
---
include/linux/once.h | 26 ++++++++++++++++++++++++++
1 file changed, 26 insertions(+)
create mode 100644 include/linux/once.h
diff --git a/include/linux/once.h b/include/linux/once.h
new file mode 100644
index 0000000..9399f37
--- /dev/null
+++ b/include/linux/once.h
@@ -0,0 +1,26 @@
+#ifndef _LINUX_ONCE_H
+#define _LINUX_ONCE_H
+
+#include <linux/compiler.h>
+
+#define DO_COND(condition, to_do) ({ \
+ int __ret = !!(condition); \
+ if (unlikely(__ret)) { \
+ to_do; \
+ } \
+ unlikely(__ret); \
+})
+
+#define DO_ONCE(to_do) ({ \
+ static bool __done; \
+ \
+ if (!__done) { \
+ __done = true; \
+ to_do; \
+ } \
+})
+
+#define DO_ONCE_COND(condition, to_do) \
+ DO_COND(condition, DO_ONCE(to_do))
+
+#endif /* _LINUX_ONCE_H */
--
1.8.3.1
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