diff options
Diffstat (limited to 'nptl/pthread_rwlock_init.c')
| -rw-r--r-- | nptl/pthread_rwlock_init.c | 39 |
1 files changed, 4 insertions, 35 deletions
diff --git a/nptl/pthread_rwlock_init.c b/nptl/pthread_rwlock_init.c index 27f25ac2ab..f664dd8104 100644 --- a/nptl/pthread_rwlock_init.c +++ b/nptl/pthread_rwlock_init.c @@ -1,4 +1,4 @@ -/* Copyright (C) 2002, 2007 Free Software Foundation, Inc. +/* Copyright (C) 2002 Free Software Foundation, Inc. This file is part of the GNU C Library. Contributed by Ulrich Drepper <drepper@redhat.com>, 2002. @@ -18,7 +18,6 @@ 02111-1307 USA. */ #include "pthreadP.h" -#include <kernel-features.h> static const struct pthread_rwlockattr default_attr = @@ -38,44 +37,14 @@ __pthread_rwlock_init (rwlock, attr) iattr = ((const struct pthread_rwlockattr *) attr) ?: &default_attr; rwlock->__data.__lock = 0; + rwlock->__data.__flags + = iattr->lockkind == PTHREAD_RWLOCK_PREFER_WRITER_NONRECURSIVE_NP; rwlock->__data.__nr_readers = 0; + rwlock->__data.__writer = 0; rwlock->__data.__readers_wakeup = 0; rwlock->__data.__writer_wakeup = 0; rwlock->__data.__nr_readers_queued = 0; rwlock->__data.__nr_writers_queued = 0; - rwlock->__data.__writer = 0; - - rwlock->__data.__flags - = iattr->lockkind == PTHREAD_RWLOCK_PREFER_WRITER_NONRECURSIVE_NP; - - /* 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. */ -#ifdef __ASSUME_PRIVATE_FUTEX - rwlock->__data.__shared = (iattr->pshared == PTHREAD_PROCESS_PRIVATE - ? 0 : FUTEX_PRIVATE_FLAG); -#else - rwlock->__data.__shared = (iattr->pshared == PTHREAD_PROCESS_PRIVATE - ? 0 - : THREAD_GETMEM (THREAD_SELF, - header.private_futex)); -#endif - - rwlock->__data.__pad1 = 0; - rwlock->__data.__pad2 = 0; return 0; } |