diff options
Diffstat (limited to 'lib/once.c')
| -rw-r--r-- | lib/once.c | 30 |
1 files changed, 30 insertions, 0 deletions
diff --git a/lib/once.c b/lib/once.c index 59149bf3bfb4..351f66aad310 100644 --- a/lib/once.c +++ b/lib/once.c @@ -66,3 +66,33 @@ void __do_once_done(bool *done, struct static_key_true *once_key, once_disable_jump(once_key, mod); } EXPORT_SYMBOL(__do_once_done); + +static DEFINE_MUTEX(once_mutex); + +bool __do_once_slow_start(bool *done) + __acquires(once_mutex) +{ + mutex_lock(&once_mutex); + if (*done) { + mutex_unlock(&once_mutex); + /* Keep sparse happy by restoring an even lock count on + * this mutex. In case we return here, we don't call into + * __do_once_done but return early in the DO_ONCE_SLOW() macro. + */ + __acquire(once_mutex); + return false; + } + + return true; +} +EXPORT_SYMBOL(__do_once_slow_start); + +void __do_once_slow_done(bool *done, struct static_key_true *once_key, + struct module *mod) + __releases(once_mutex) +{ + *done = true; + mutex_unlock(&once_mutex); + once_disable_jump(once_key, mod); +} +EXPORT_SYMBOL(__do_once_slow_done); |