Received-SPF: pass (google.com: domain of linux-kernel+bounces-170996-linux.lists.archive=gmail.com@vger.kernel.org designates 147.75.80.249 as permitted sender) client-ip=147.75.80.249;
From: "Uladzislau Rezki (Sony)" <urezki@gmail.com>
To: "Paul E . McKenney" <paulmck@kernel.org>
Cc: RCU <rcu@vger.kernel.org>,
	Neeraj upadhyay <Neeraj.Upadhyay@amd.com>,
	Boqun Feng <boqun.feng@gmail.com>,
	Hillf Danton <hdanton@sina.com>,
	Joel Fernandes <joel@joelfernandes.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Uladzislau Rezki <urezki@gmail.com>,
	Oleksiy Avramchenko <oleksiy.avramchenko@sony.com>,
	Frederic Weisbecker <frederic@kernel.org>,
	Linus Torvalds <torvalds@linux-foundation.org>
Subject: [PATCH 40/48] rcutorture: Fix rcu_torture_one_read() pipe_count overflow comment
Date: Tue,  7 May 2024 11:35:22 +0200
Message-Id: <20240507093530.3043-41-urezki@gmail.com>
In-Reply-To: <20240507093530.3043-1-urezki@gmail.com>
References: <20240507093530.3043-1-urezki@gmail.com>
Precedence: bulk
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit

From: "Paul E. McKenney" <paulmck@kernel.org>

The "pipe_count > RCU_TORTURE_PIPE_LEN" check has a comment saying "Should
not happen, but...".  This is only true when testing an RCU whose grace
periods are always long enough.  This commit therefore fixes this comment.

Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Closes: https://lore.kernel.org/lkml/CAHk-=wi7rJ-eGq+xaxVfzFEgbL9tdf6Kc8Z89rCpfcQOKm74Tw@mail.gmail.com/
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
---
 kernel/rcu/rcutorture.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index 6b821a7037b0..0cb5452ecd94 100644
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -2000,7 +2000,8 @@ static bool rcu_torture_one_read(struct torture_random_state *trsp, long myid)
 	preempt_disable();
 	pipe_count = READ_ONCE(p->rtort_pipe_count);
 	if (pipe_count > RCU_TORTURE_PIPE_LEN) {
-		/* Should not happen, but... */
+		// Should not happen in a correct RCU implementation,
+		// happens quite often for torture_type=busted.
 		pipe_count = RCU_TORTURE_PIPE_LEN;
 	}
 	completed = cur_ops->get_gp_seq();
-- 
2.39.2