diff options
Diffstat (limited to 'nptl/pthread_rwlock_init.c')
| -rw-r--r-- | nptl/pthread_rwlock_init.c | 25 |
1 files changed, 4 insertions, 21 deletions
diff --git a/nptl/pthread_rwlock_init.c b/nptl/pthread_rwlock_init.c index 1687f22..764ba11 100644 --- a/nptl/pthread_rwlock_init.c +++ b/nptl/pthread_rwlock_init.c @@ -18,7 +18,6 @@ #include "pthreadP.h" #include <string.h> -#include <kernel-features.h> static const struct pthread_rwlockattr default_rwlockattr = @@ -28,6 +27,7 @@ static const struct pthread_rwlockattr default_rwlockattr = }; +/* See pthread_rwlock_common.c. */ int __pthread_rwlock_init (pthread_rwlock_t *rwlock, const pthread_rwlockattr_t *attr) @@ -38,27 +38,10 @@ __pthread_rwlock_init (pthread_rwlock_t *rwlock, memset (rwlock, '\0', sizeof (*rwlock)); - rwlock->__data.__flags - = iattr->lockkind == PTHREAD_RWLOCK_PREFER_WRITER_NONRECURSIVE_NP; + rwlock->__data.__flags = iattr->lockkind; - /* The __SHARED field is computed to minimize the work that needs to - be done while handling the futex. There are two inputs: the - availability of private futexes and whether the rwlock is shared - or private. Unfortunately the value of a private rwlock is - fixed: it must be zero. The PRIVATE_FUTEX flag has the value - 0x80 in case private futexes are available and zero otherwise. - This leads to the following table: - - | pshared | result - | shared private | shared private | - ------------+-----------------+-----------------+ - !avail 0 | 0 0 | 0 0 | - avail 0x80 | 0x80 0 | 0 0x80 | - - If the pshared value is in locking functions XORed with avail - we get the expected result. */ - rwlock->__data.__shared = (iattr->pshared == PTHREAD_PROCESS_PRIVATE - ? 0 : FUTEX_PRIVATE_FLAG); + /* The value of __SHARED in a private rwlock must be zero. */ + rwlock->__data.__shared = (iattr->pshared != PTHREAD_PROCESS_PRIVATE); return 0; } |