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From:   Hou Tao <houtao1@huawei.com>
To:     "Paul E. McKenney" <paulmck@kernel.org>
CC:     Josh Triplett <josh@joshtriplett.org>,
        Davidlohr Bueso <dave@stgolabs.net>,
        <linux-kernel@vger.kernel.org>, <rcu@vger.kernel.org>,
        <houtao1@huawei.com>
Subject: [PATCH v2 1/2] locktorture: doesn't check nreaders_stress when no readlock support
Date:   Fri, 18 Sep 2020 19:44:24 +0800
Message-ID: <20200918114424.100852-1-houtao1@huawei.com>
In-Reply-To: <20200918033755.GS29330@paulmck-ThinkPad-P72>
References: <20200918033755.GS29330@paulmck-ThinkPad-P72>
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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@huawei.com>
---
 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