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From:   paulmck@kernel.org
To:     rcu@vger.kernel.org
Cc:     linux-kernel@vger.kernel.org, kernel-team@fb.com, mingo@kernel.org,
        jiangshanlai@gmail.com, akpm@linux-foundation.org,
        mathieu.desnoyers@efficios.com, josh@joshtriplett.org,
        tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org,
        dhowells@redhat.com, edumazet@google.com, fweisbec@gmail.com,
        oleg@redhat.com, joel@joelfernandes.org,
        Hou Tao <houtao1@huawei.com>,
        "Paul E . McKenney" <paulmck@kernel.org>
Subject: [PATCH tip/core/rcu 13/28] locktorture: Ignore nreaders_stress if no readlock support
Date:   Thu,  5 Nov 2020 15:47:04 -0800
Message-Id: <20201105234719.23307-13-paulmck@kernel.org>
In-Reply-To: <20201105234658.GA23142@paulmck-ThinkPad-P72>
References: <20201105234658.GA23142@paulmck-ThinkPad-P72>
Precedence: bulk

From: Hou Tao <houtao1@huawei.com>

Exclusive locks do not have readlock support, which means that a
locktorture run with the following module parameters will do nothing:

 torture_type=mutex_lock nwriters_stress=0 nreaders_stress=1

This commit therefore rejects this combination for exclusive locks by
returning -EINVAL during module init.

Signed-off-by: Hou Tao <houtao1@huawei.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
 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 316531d..046ea2d 100644
--- a/kernel/locking/locktorture.c
+++ b/kernel/locking/locktorture.c
@@ -870,7 +870,8 @@ 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;
-- 
2.9.5