diff options
Diffstat (limited to 'freebsd/sys/sys/refcount.h')
| -rw-r--r-- | freebsd/sys/sys/refcount.h | 33 |
1 files changed, 24 insertions, 9 deletions
diff --git a/freebsd/sys/sys/refcount.h b/freebsd/sys/sys/refcount.h index 41713147..0cc4ee6c 100644 --- a/freebsd/sys/sys/refcount.h +++ b/freebsd/sys/sys/refcount.h @@ -37,6 +37,7 @@ #ifdef _KERNEL #include <sys/systm.h> #else +#include <stdbool.h> #define KASSERT(exp, msg) /* */ #endif @@ -55,7 +56,21 @@ refcount_acquire(volatile u_int *count) atomic_add_int((volatile int *)count, 1); } -static __inline int +static __inline __result_use_check bool +refcount_acquire_checked(volatile u_int *count) +{ + u_int lcount; + + for (lcount = *count;;) { + if (__predict_false(lcount + 1 < lcount)) + return (false); + if (__predict_true(atomic_fcmpset_int(count, &lcount, + lcount + 1) == 1)) + return (true); + } +} + +static __inline bool refcount_release(volatile u_int *count) { u_int old; @@ -64,7 +79,7 @@ refcount_release(volatile u_int *count) old = atomic_fetchadd_int((volatile int *)count, -1); KASSERT(old > 0, ("refcount %p is zero", count)); if (old > 1) - return (0); + return (false); /* * Last reference. Signal the user to call the destructor. @@ -73,7 +88,7 @@ refcount_release(volatile u_int *count) * at the start of the function synchronized with this fence. */ atomic_thread_fence_acq(); - return (1); + return (true); } /* @@ -82,7 +97,7 @@ refcount_release(volatile u_int *count) * * A temporary hack until refcount_* APIs are sorted out. */ -static __inline __result_use_check int +static __inline __result_use_check bool refcount_acquire_if_not_zero(volatile u_int *count) { u_int old; @@ -91,13 +106,13 @@ refcount_acquire_if_not_zero(volatile u_int *count) for (;;) { KASSERT(old < UINT_MAX, ("refcount %p overflowed", count)); if (old == 0) - return (0); + return (false); if (atomic_fcmpset_int(count, &old, old + 1)) - return (1); + return (true); } } -static __inline __result_use_check int +static __inline __result_use_check bool refcount_release_if_not_last(volatile u_int *count) { u_int old; @@ -106,9 +121,9 @@ refcount_release_if_not_last(volatile u_int *count) for (;;) { KASSERT(old > 0, ("refcount %p is zero", count)); if (old == 1) - return (0); + return (false); if (atomic_fcmpset_int(count, &old, old - 1)) - return (1); + return (true); } } |