[PATCH v2 2/3] lockdep: add lockdep lock state defines

[Shuah Khan]

Adds defines for lock state returns from lock_is_held_type() based on
Johannes Berg's suggestions as it make it easier to read and maintain
the lock states. These are defines and a enum to avoid changes to
lock_is_held_type() and lockdep_is_held() return types.

Link: https://lore.kernel.org/lkml/37a29c383bff2fb1605241ee6c7c9be3784fb3c6.1613171185.git.skhan@linuxfoundation.org/
Link: https://lore.kernel.org/linux-wireless/871rdmu9z9.fsf@codeaurora.org/
Signed-off-by: Shuah Khan <skhan at linuxfoundation.org>
---
 include/linux/lockdep.h  | 11 +++++++++--
 kernel/locking/lockdep.c |  3 ++-
 2 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h
index 93eb5f797fc1..7c2622854152 100644
--- a/include/linux/lockdep.h
+++ b/include/linux/lockdep.h
@@ -261,6 +261,11 @@ extern void lock_acquire(struct lockdep_map *lock, unsigned int subclass,
 
 extern void lock_release(struct lockdep_map *lock, unsigned long ip);
 
+/* lock_is_held_type() returns */
+#define LOCK_STATE_UNKNOWN	-1
+#define LOCK_STATE_NOT_HELD	0
+#define LOCK_STATE_HELD		1
+
 /*
  * Same "read" as for lock_acquire(), except -1 means any.
  */
@@ -295,11 +300,13 @@ extern void lock_unpin_lock(struct lockdep_map *lock, struct pin_cookie);
 #define lockdep_depth(tsk)	(debug_locks ? (tsk)->lockdep_depth : 0)
 
 #define lockdep_assert_held(l)	do {					\
-		WARN_ON(debug_locks && lockdep_is_held(l) == 0);	\
+		WARN_ON(debug_locks &&					\
+			lockdep_is_held(l) == LOCK_STATE_NOT_HELD);	\
 	} while (0)
 
 #define lockdep_assert_not_held(l)	do {				\
-		WARN_ON(debug_locks && lockdep_is_held(l) == 1);	\
+		WARN_ON(debug_locks &&					\
+			lockdep_is_held(l) == LOCK_STATE_HELD);		\
 	} while (0)
 
 #define lockdep_assert_held_write(l)	do {			\
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index d3299fd85c4a..e3898c888ad2 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -54,6 +54,7 @@
 #include <linux/nmi.h>
 #include <linux/rcupdate.h>
 #include <linux/kprobes.h>
+#include <linux/lockdep.h>
 
 #include <asm/sections.h>
 
@@ -5475,7 +5476,7 @@ noinstr int lock_is_held_type(const struct lockdep_map *lock, int read)
 		/* avoid false negative lockdep_assert_not_held()
 		 * and lockdep_assert_held()
 		 */
-		return -1;
+		return LOCK_STATE_UNKNOWN;
 
 	raw_local_irq_save(flags);
 	check_flags(flags);
-- 
2.27.0