linux-kernel - [PATCH v2 22/23] locking/lockdep: Adjust new bit cases in mark

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Message-Id: <20190506081939.74287-23-duyuyang@gmail.com>
Date:   Mon,  6 May 2019 16:19:38 +0800
From:   Yuyang Du <duyuyang@...il.com>
To:     peterz@...radead.org, will.deacon@....com, mingo@...nel.org
Cc:     bvanassche@....org, ming.lei@...hat.com, frederic@...nel.org,
        tglx@...utronix.de, linux-kernel@...r.kernel.org,
        Yuyang Du <duyuyang@...il.com>
Subject: [PATCH v2 22/23] locking/lockdep: Adjust new bit cases in mark_lock

The new bit can be any possible lock usage except it is garbage, so the
cases in switch can be made simpler. Warn early on if wrong usage bit is
passed without taking locks. No functional change.

Signed-off-by: Yuyang Du <duyuyang@...il.com>
---
 kernel/locking/lockdep.c | 21 +++++++--------------
 1 file changed, 7 insertions(+), 14 deletions(-)

diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 79bc6cd..24e3bca 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -3581,6 +3581,11 @@ static int mark_lock(struct task_struct *curr, struct held_lock *this,
 {
 	unsigned int new_mask = 1 << new_bit, ret = 1;
 
+	if (new_bit >= LOCK_USAGE_STATES) {
+		DEBUG_LOCKS_WARN_ON(1);
+		return 0;
+	}
+
 	/*
 	 * If already set then do not dirty the cacheline,
 	 * nor do any checks:
@@ -3604,25 +3609,13 @@ static int mark_lock(struct task_struct *curr, struct held_lock *this,
 		return 0;
 
 	switch (new_bit) {
-#define LOCKDEP_STATE(__STATE)			\
-	case LOCK_USED_IN_##__STATE:		\
-	case LOCK_USED_IN_##__STATE##_READ:	\
-	case LOCK_ENABLED_##__STATE:		\
-	case LOCK_ENABLED_##__STATE##_READ:
-#include "lockdep_states.h"
-#undef LOCKDEP_STATE
-		ret = mark_lock_irq(curr, this, new_bit);
-		if (!ret)
-			return 0;
-		break;
 	case LOCK_USED:
 		debug_atomic_dec(nr_unused_locks);
 		break;
 	default:
-		if (!debug_locks_off_graph_unlock())
+		ret = mark_lock_irq(curr, this, new_bit);
+		if (!ret)
 			return 0;
-		WARN_ON(1);
-		return 0;
 	}
 
 	graph_unlock();
-- 
1.8.3.1