[tip:locking/core] locking/lockdep: Make it clear that what lock_class::key points at is not modified

[tip-bot for Bart Van Assche]

Commit-ID:  364f6afc4f5537b79cf454eb35cae92920676075
Gitweb:     https://git.kernel.org/tip/364f6afc4f5537b79cf454eb35cae92920676075
Author:     Bart Van Assche <bvanassche@xxxxxxx>
AuthorDate: Mon, 22 Jul 2019 11:24:40 -0700
Committer:  Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Thu, 25 Jul 2019 15:43:26 +0200

locking/lockdep: Make it clear that what lock_class::key points at is not modified

This patch does not change the behavior of the lockdep code.

Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Waiman Long <longman@xxxxxxxxxx>
Cc: Will Deacon <will.deacon@xxxxxxx>
Link: https://lkml.kernel.org/r/20190722182443.216015-2-bvanassche@xxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
 include/linux/lockdep.h            | 2 +-
 kernel/locking/lockdep.c           | 2 +-
 kernel/locking/lockdep_internals.h | 3 ++-
 kernel/locking/lockdep_proc.c      | 2 +-
 4 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h
index 0b0d7259276d..cdb3c2f06092 100644
--- a/include/linux/lockdep.h
+++ b/include/linux/lockdep.h
@@ -97,7 +97,7 @@ struct lock_class {
 	 */
 	struct list_head		locks_after, locks_before;
 
-	struct lockdep_subclass_key	*key;
+	const struct lockdep_subclass_key *key;
 	unsigned int			subclass;
 	unsigned int			dep_gen_id;
 
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 4861cf8e274b..af6627866191 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -511,7 +511,7 @@ static const char *usage_str[] =
 };
 #endif
 
-const char * __get_key_name(struct lockdep_subclass_key *key, char *str)
+const char *__get_key_name(const struct lockdep_subclass_key *key, char *str)
 {
 	return kallsyms_lookup((unsigned long)key, NULL, NULL, NULL, str);
 }
diff --git a/kernel/locking/lockdep_internals.h b/kernel/locking/lockdep_internals.h
index cc83568d5012..2e518369add4 100644
--- a/kernel/locking/lockdep_internals.h
+++ b/kernel/locking/lockdep_internals.h
@@ -116,7 +116,8 @@ extern struct lock_chain lock_chains[];
 extern void get_usage_chars(struct lock_class *class,
 			    char usage[LOCK_USAGE_CHARS]);
 
-extern const char * __get_key_name(struct lockdep_subclass_key *key, char *str);
+extern const char *__get_key_name(const struct lockdep_subclass_key *key,
+				  char *str);
 
 struct lock_class *lock_chain_get_class(struct lock_chain *chain, int i);
 
diff --git a/kernel/locking/lockdep_proc.c b/kernel/locking/lockdep_proc.c
index bda006f8a88b..ed9842425cac 100644
--- a/kernel/locking/lockdep_proc.c
+++ b/kernel/locking/lockdep_proc.c
@@ -399,7 +399,7 @@ static void seq_lock_time(struct seq_file *m, struct lock_time *lt)
 
 static void seq_stats(struct seq_file *m, struct lock_stat_data *data)
 {
-	struct lockdep_subclass_key *ckey;
+	const struct lockdep_subclass_key *ckey;
 	struct lock_class_stats *stats;
 	struct lock_class *class;
 	const char *cname;