New pthread_barrier algorithm to fulfill barrier destruction requirements.

The previous barrier implementation did not fulfill the POSIX requirements
for when a barrier can be destroyed.  Specifically, it was possible that
threads that haven't noticed yet that their round is complete still access
the barrier's memory, and that those accesses can happen after the barrier
has been legally destroyed.
The new algorithm does not have this issue, and it avoids using a lock
internally.

1 files changed, 1 insertions, 5 deletions

diff --git a/nptl/pthread_barrierattr_setpshared.c b/nptl/pthread_barrierattr_setpshared.c
index 8cc1bf8e8e..d41b041e1e 100644
--- a/nptl/pthread_barrierattr_setpshared.c
+++ b/nptl/pthread_barrierattr_setpshared.c
@@ -24,15 +24,11 @@
 int
 pthread_barrierattr_setpshared (pthread_barrierattr_t *attr, int pshared)
 {
-  struct pthread_barrierattr *iattr;
-
   int err = futex_supports_pshared (pshared);
   if (err != 0)
     return err;
 
-  iattr = (struct pthread_barrierattr *) attr;
-
-  iattr->pshared = pshared;
+  ((struct pthread_barrierattr *) attr)->pshared = pshared;
 
   return 0;
 }