[PATCH v2 1/2] locktorture: doesn't check nreaders_stress when no readlock support

[Hou Tao]

When do locktorture for exclusive lock which doesn't have readlock
support, the following module parameters will be considered as valid:

 torture_type=mutex_lock nwriters_stress=0 nreaders_stress=1

But locktorture will do nothing useful, so instead of permitting
these useless parameters, let's reject these parameters by returning
-EINVAL during module init.

Signed-off-by: Hou Tao <houtao1@xxxxxxxxxx>
---
 kernel/locking/locktorture.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c
index 9cfa5e89cff7f..bebdf98e6cd78 100644
--- a/kernel/locking/locktorture.c
+++ b/kernel/locking/locktorture.c
@@ -868,7 +868,8 @@ static int __init lock_torture_init(void)
 		goto unwind;
 	}
 
-	if (nwriters_stress == 0 && nreaders_stress == 0) {
+	if (nwriters_stress == 0 &&
+	    (!cxt.cur_ops->readlock || nreaders_stress == 0)) {
 		pr_alert("lock-torture: must run at least one locking thread\n");
 		firsterr = -EINVAL;
 		goto unwind;
-- 
2.25.0.4.g0ad7144999