linux-kernel - [tip:locking/core] locking/lockdep: Adjust new bit cases in mark

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Message-ID: <tip-4d56330df22dd9dd9a24f147014f60ee4c914fb8@git.kernel.org>
Date:   Mon, 3 Jun 2019 06:21:40 -0700
From:   tip-bot for Yuyang Du <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     hpa@...or.com, linux-kernel@...r.kernel.org,
        torvalds@...ux-foundation.org, tglx@...utronix.de,
        mingo@...nel.org, peterz@...radead.org, duyuyang@...il.com
Subject: [tip:locking/core] locking/lockdep: Adjust new bit cases in
 mark_lock

Commit-ID:  4d56330df22dd9dd9a24f147014f60ee4c914fb8
Gitweb:     https://git.kernel.org/tip/4d56330df22dd9dd9a24f147014f60ee4c914fb8
Author:     Yuyang Du <duyuyang@...il.com>
AuthorDate: Mon, 6 May 2019 16:19:38 +0800
Committer:  Ingo Molnar <mingo@...nel.org>
CommitDate: Mon, 3 Jun 2019 11:55:52 +0200

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>
Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: bvanassche@....org
Cc: frederic@...nel.org
Cc: ming.lei@...hat.com
Cc: will.deacon@....com
Link: https://lkml.kernel.org/r/20190506081939.74287-23-duyuyang@gmail.com
Signed-off-by: Ingo Molnar <mingo@...nel.org>
---
 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 1123e7e6c78d..9c4e2a7547d3 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -3582,6 +3582,11 @@ 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:
@@ -3605,25 +3610,13 @@ 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();