| Quellcodebibliothek Statistik Leitseite products/sources/formale Sprachen/C/Linux/include/linux/ (Open Source Betriebssystem Version 6.17.9©) Datei vom 24.10.2025 mit Größe 1 kB |
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Quelle call_once.h Sprache: C |
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#ifndef _LINUX_CALL_ONCE_H
#define _LINUX_CALL_ONCE_H #include <linux/types.h> #include <linux/mutex.h> #define ONCE_NOT_STARTED 0 #define ONCE_RUNNING 1 #define ONCE_COMPLETED 2 struct once { atomic_t state; struct mutex lock; }; static inline void __once_init(struct once *once, const char *name, struct lock_class_key *key) { atomic_set(&once->state, ONCE_NOT_STARTED); __mutex_init(&once->lock, name, key); } #define once_init(once) \ do { \ static struct lock_class_key __key; \ __once_init((once), #once, &__key); \ } while (0) /* * call_once - Ensure a function has been called exactly once * * @once: Tracking struct * @cb: Function to be called * * If @once has never completed successfully before, call @cb and, if * it returns a zero or positive value, mark @once as completed. Return * the value returned by @cb * * If @once has completed succesfully before, return 0. * * The call to @cb is implicitly surrounded by a mutex, though for * efficiency the * function avoids taking it after the first call. */ static inline int call_once(struct once *once, int (*cb)(struct once *)) { int r, state; /* Pairs with atomic_set_release() below. */ if (atomic_read_acquire(&once->state) == ONCE_COMPLETED) return 0; guard(mutex)(&once->lock); state = atomic_read(&once->state); if (unlikely(state != ONCE_NOT_STARTED)) return WARN_ON_ONCE(state != ONCE_COMPLETED) ? -EINVAL : 0; atomic_set(&once->state, ONCE_RUNNING); r = cb(once); if (r < 0) atomic_set(&once->state, ONCE_NOT_STARTED); else atomic_set_release(&once->state, ONCE_COMPLETED); return r; } #endif /* _LINUX_CALL_ONCE_H */ ¤ Dauer der Verarbeitung: 0.23 Sekunden (vorverarbeitet) ¤*© Formatika GbR, Deutschland |
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2026-03-28