Function __rw_assert

freebsd/kern/kern_rwlock.c:1444–1519

* In the non-WITNESS case, rw_assert() can only detect that at least * *some* thread owns an rlock, but it cannot guarantee that *this* * thread owns an rlock. */

 * thread owns an rlock.
 */
void
__rw_assert(const volatile uintptr_t *c, int what, const char *file, int line)
{
	const struct rwlock *rw;

	if (SCHEDULER_STOPPED())
		return;

	rw = rwlock2rw(c);

	switch (what) {
	case RA_LOCKED:
	case RA_LOCKED | RA_RECURSED:
	case RA_LOCKED | RA_NOTRECURSED:
	case RA_RLOCKED:
	case RA_RLOCKED | RA_RECURSED:
	case RA_RLOCKED | RA_NOTRECURSED:
#ifdef WITNESS
		witness_assert(&rw->lock_object, what, file, line);
#else
		/*
		 * If some other thread has a write lock or we have one
		 * and are asserting a read lock, fail.  Also, if no one
		 * has a lock at all, fail.
		 */
		if (rw->rw_lock == RW_UNLOCKED ||
		    (!(rw->rw_lock & RW_LOCK_READ) && (what & RA_RLOCKED ||
		    rw_wowner(rw) != curthread)))
			panic("Lock %s not %slocked @ %s:%d\n",
			    rw->lock_object.lo_name, (what & RA_RLOCKED) ?
			    "read " : "", file, line);

		if (!(rw->rw_lock & RW_LOCK_READ) && !(what & RA_RLOCKED)) {
			if (rw_recursed(rw)) {
				if (what & RA_NOTRECURSED)
					panic("Lock %s recursed @ %s:%d\n",
					    rw->lock_object.lo_name, file,
					    line);
			} else if (what & RA_RECURSED)
				panic("Lock %s not recursed @ %s:%d\n",
				    rw->lock_object.lo_name, file, line);
		}
#endif
		break;
	case RA_WLOCKED:
	case RA_WLOCKED | RA_RECURSED:
	case RA_WLOCKED | RA_NOTRECURSED:
		if (rw_wowner(rw) != curthread)
			panic("Lock %s not exclusively locked @ %s:%d\n",
			    rw->lock_object.lo_name, file, line);
		if (rw_recursed(rw)) {
			if (what & RA_NOTRECURSED)
				panic("Lock %s recursed @ %s:%d\n",
				    rw->lock_object.lo_name, file, line);
		} else if (what & RA_RECURSED)
			panic("Lock %s not recursed @ %s:%d\n",
			    rw->lock_object.lo_name, file, line);
		break;