diff options
Diffstat (limited to 'libc/nscd/nscd-client.h')
| -rw-r--r-- | libc/nscd/nscd-client.h | 22 |
1 files changed, 20 insertions, 2 deletions
diff --git a/libc/nscd/nscd-client.h b/libc/nscd/nscd-client.h index e57a23c05..aef76e8fd 100644 --- a/libc/nscd/nscd-client.h +++ b/libc/nscd/nscd-client.h @@ -1,5 +1,4 @@ -/* Copyright (c) 1998, 1999, 2000, 2003, 2004, 2005, 2006, 2007, 2009, 2011 - Free Software Foundation, Inc. +/* Copyright (c) 1998-2012 Free Software Foundation, Inc. This file is part of the GNU C Library. Contributed by Thorsten Kukuk <kukuk@suse.de>, 1998. @@ -322,6 +321,25 @@ struct locked_map_ptr }; #define libc_locked_map_ptr(class, name) class struct locked_map_ptr name +/* Try acquiring lock for mapptr, returns true if it succeeds, false + if not. */ +static inline bool +__nscd_acquire_maplock (volatile struct locked_map_ptr *mapptr) +{ + int cnt = 0; + while (__builtin_expect (atomic_compare_and_exchange_val_acq (&mapptr->lock, + 1, 0) != 0, 0)) + { + // XXX Best number of rounds? + if (__builtin_expect (++cnt > 5, 0)) + return false; + + atomic_delay (); + } + + return true; +} + /* Open socket connection to nscd server. */ extern int __nscd_open_socket (const char *key, size_t keylen, |