linux-kernel - [PATCH 01/10] lib: Use rcu_preempt_depth() to replace current->rcu_read_lock

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Message-Id: <20240328075318.83039-2-jiangshanlai@gmail.com>
Date: Thu, 28 Mar 2024 15:53:09 +0800
From: Lai Jiangshan <jiangshanlai@...il.com>
To: linux-kernel@...r.kernel.org
Cc: rcu@...r.kernel.org,
	x86@...nel.org,
	Lai Jiangshan <jiangshan.ljs@...group.com>,
	"Paul E. McKenney" <paulmck@...nel.org>,
	Peter Zijlstra <peterz@...radead.org>,
	Frederic Weisbecker <frederic@...nel.org>,
	Ingo Molnar <mingo@...hat.com>,
	Will Deacon <will@...nel.org>,
	Waiman Long <longman@...hat.com>,
	Boqun Feng <boqun.feng@...il.com>,
	Andrew Morton <akpm@...ux-foundation.org>
Subject: [PATCH 01/10] lib: Use rcu_preempt_depth() to replace current->rcu_read_lock_nesting

From: Lai Jiangshan <jiangshan.ljs@...group.com>

Use the general wrapper rcu_preempt_depth() instead of the open code.

Prepare for enabling per-cpu rcu_preempt_count, in which case
current->rcu_read_lock_nesting might not be synced with the real depth.

Cc: "Paul E. McKenney" <paulmck@...nel.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Frederic Weisbecker <frederic@...nel.org>
Signed-off-by: Lai Jiangshan <jiangshan.ljs@...group.com>
---
 lib/locking-selftest.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/lib/locking-selftest.c b/lib/locking-selftest.c
index 6f6a5fc85b42..9bb41fb18088 100644
--- a/lib/locking-selftest.c
+++ b/lib/locking-selftest.c
@@ -1434,7 +1434,7 @@ static void dotest(void (*testcase_fn)(void), int expected, int lockclass_mask)
 #ifdef CONFIG_SMP
 	int saved_mgd_count = current->migration_disabled;
 #endif
-	int saved_rcu_count = current->rcu_read_lock_nesting;
+	int saved_rcu_count = rcu_preempt_depth();
 #endif
 
 	WARN_ON(irqs_disabled());
@@ -1476,9 +1476,9 @@ static void dotest(void (*testcase_fn)(void), int expected, int lockclass_mask)
 		migrate_enable();
 #endif
 
-	while (current->rcu_read_lock_nesting > saved_rcu_count)
+	while (rcu_preempt_depth() > saved_rcu_count)
 		rcu_read_unlock();
-	WARN_ON_ONCE(current->rcu_read_lock_nesting < saved_rcu_count);
+	WARN_ON_ONCE(rcu_preempt_depth() < saved_rcu_count);
 #endif
 
 #ifdef CONFIG_TRACE_IRQFLAGS
-- 
2.19.1.6.gb485710b