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authorUlrich Drepper <drepper@redhat.com>2000-07-19 06:24:30 +0000
committerUlrich Drepper <drepper@redhat.com>2000-07-19 06:24:30 +0000
commit056f707c8618062023a79fdbc6ec19ac482c63dd (patch)
treefe3f8fffc0c85a938dd077474827d1f8c3bf6ec6
parenta48297fdf310f0bf0fb29df1e185dd5f1561c1c1 (diff)
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Update.
* spinlock.h (__pthread_alt_trylock): Fix code used if no compare&swap is available.
-rw-r--r--linuxthreads/ChangeLog3
-rw-r--r--linuxthreads/spinlock.h14
2 files changed, 16 insertions, 1 deletions
diff --git a/linuxthreads/ChangeLog b/linuxthreads/ChangeLog
index 1351c25495..f14cf0d4a5 100644
--- a/linuxthreads/ChangeLog
+++ b/linuxthreads/ChangeLog
@@ -1,5 +1,8 @@
2000-07-18 Ulrich Drepper <drepper@redhat.com>
+ * spinlock.h (__pthread_alt_trylock): Fix code used if no
+ compare&swap is available.
+
* spinlock.h (__pthread_trylock): Use __compare_and_swap, not
compare_and_swap.
diff --git a/linuxthreads/spinlock.h b/linuxthreads/spinlock.h
index 17efd183cd..703b72d65e 100644
--- a/linuxthreads/spinlock.h
+++ b/linuxthreads/spinlock.h
@@ -149,7 +149,19 @@ static inline int __pthread_alt_trylock (struct _pthread_fastlock * lock)
#endif
#if !defined HAS_COMPARE_AND_SWAP || defined TEST_FOR_COMPARE_AND_SWAP
{
- return (testandset(&lock->__spinlock) ? EBUSY : 0);
+ int res = EBUSY;
+
+ if (testandset(&lock->__spinlock) == 0)
+ {
+ if (lock->__status == 0)
+ {
+ lock->__status = 1;
+ WRITE_MEMORY_BARRIER();
+ res = 0;
+ }
+ lock->__spinlock = 0;
+ }
+ return res;
}
#endif