X-Git-Url: https://git.lttng.org/?p=urcu.git;a=blobdiff_plain;f=urcu-qsbr-static.h;h=c0467cd0e1606c87a522e56d2299716cf6402b3e;hp=57f0c50a8b899b2db0fc77084b052beb534d9d5e;hb=e72f49371b233637eaf143265a73c7322d0710fd;hpb=555704664c109a2be7290e1f5ce3806d0c28b5d9 diff --git a/urcu-qsbr-static.h b/urcu-qsbr-static.h index 57f0c50..c0467cd 100644 --- a/urcu-qsbr-static.h +++ b/urcu-qsbr-static.h @@ -173,6 +173,17 @@ extern unsigned long urcu_gp_ctr; extern unsigned long __thread rcu_reader_qs_gp; +#if (BITS_PER_LONG < 64) +static inline int rcu_gp_ongoing(unsigned long *value) +{ + unsigned long reader_gp; + + if (value == NULL) + return 0; + reader_gp = LOAD_SHARED(*value); + return reader_gp && ((reader_gp ^ urcu_gp_ctr) & RCU_GP_CTR); +} +#else /* !(BITS_PER_LONG < 64) */ static inline int rcu_gp_ongoing(unsigned long *value) { unsigned long reader_gp; @@ -182,6 +193,7 @@ static inline int rcu_gp_ongoing(unsigned long *value) reader_gp = LOAD_SHARED(*value); return reader_gp && (reader_gp - urcu_gp_ctr > ULONG_MAX / 2); } +#endif /* !(BITS_PER_LONG < 64) */ static inline void _rcu_read_lock(void) { @@ -232,6 +244,22 @@ static inline void _rcu_thread_online(void) STORE_SHARED(p, v); \ }) +/** + * _rcu_cmpxchg_pointer - same as rcu_assign_pointer, but tests if the pointer + * is as expected by "old". If succeeds, returns the previous pointer to the + * data structure, which can be safely freed after waiting for a quiescent state + * using synchronize_rcu(). If fails (unexpected value), returns old (which + * should not be freed !). + */ + +#define _rcu_cmpxchg_pointer(p, old, _new) \ + ({ \ + if (!__builtin_constant_p(_new) || \ + ((_new) != NULL)) \ + wmb(); \ + cmpxchg(p, old, _new); \ + }) + /** * _rcu_xchg_pointer - same as rcu_assign_pointer, but returns the previous * pointer to the data structure, which can be safely freed after waiting for a