int mutex_owned(kmutex_t *mp);
A significant portion of driver development involves properly handling multiple threads. Comments should always be used when a mutex is acquired; they are even more useful when an apparently necessary mutex is not acquired. To determine if a mutex is held by a thread, use mutex_owned(9F) within ASSERT(9F):.
void helper(void) { /* this routine should always be called with the mutex held */ ASSERT(mutex_owned(&xsp->mu)); ... }
Future releases of the Solaris operating system may only support the use of mutex_owned(9F) within ASSERT(9F) by not defining mutex_owned(9F) unless the preprocessor symbol DEBUG is defined.