mass sync with glibc nptl

[uclinux-h8/uClibc.git] / libpthread / nptl / sysdeps / unix / sysv / linux / sem_post.c

diff --git a/libpthread/nptl/sysdeps/unix/sysv/linux/sem_post.c b/libpthread/nptl/sysdeps/unix/sysv/linux/sem_post.c
index 7f0b679..7ed0df8 100644 (file)
--- a/libpthread/nptl/sysdeps/unix/sysv/linux/sem_post.c
+++ b/libpthread/nptl/sysdeps/unix/sysv/linux/sem_post.c
@@ -1,5 +1,5 @@
 /* sem_post -- post to a POSIX semaphore.  Generic futex-using version.
-   Copyright (C) 2003, 2004 Free Software Foundation, Inc.
+   Copyright (C) 2003, 2004, 2007, 2008 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Jakub Jelinek <jakub@redhat.com>, 2003.
 
@@ -27,14 +27,30 @@
 int
 __new_sem_post (sem_t *sem)
 {
-  int *futex = (int *) sem;
+  struct new_sem *isem = (struct new_sem *) sem;
 
-  int nr = atomic_increment_val (futex);
-  int err = lll_futex_wake (futex, nr);
-  if (__builtin_expect (err, 0) < 0)
+  __typeof (isem->value) cur;
+  do
     {
-      __set_errno (-err);
-      return -1;
+      cur = isem->value;
+      if (isem->value == SEM_VALUE_MAX)
+       {
+         __set_errno (EOVERFLOW);
+         return -1;
+       }
+    }
+  while (atomic_compare_and_exchange_bool_acq (&isem->value, cur + 1, cur));
+
+  atomic_full_barrier ();
+  if (isem->nwaiters > 0)
+    {
+      int err = lll_futex_wake (&isem->value, 1,
+                               isem->private ^ FUTEX_PRIVATE_FLAG);
+      if (__builtin_expect (err, 0) < 0)
+       {
+         __set_errno (-err);
+         return -1;
+       }
     }
   return 0;
 }