lockdep: Add lockdep lock state defines

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.

Updates to lock_is_held_type() and  __lock_is_held() to use the new
defines.
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/linux-wireless/871rdmu9z9.fsf@codeaurora.org/

include/linux/lockdep.h

@@ -268,6 +268,11 @@ 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.
  */
@@ -302,11 +307,13 @@ 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 {			\

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>
 
@@ -5252,13 +5253,13 @@ int __lock_is_held(const struct lockdep_map *lock, int read)
 
 		if (match_held_lock(hlock, lock)) {
 			if (read == -1 || hlock->read == read)
-				return 1;
+				return LOCK_STATE_HELD;
 
-			return 0;
+			return LOCK_STATE_NOT_HELD;
 		}
 	}
 
-	return 0;
+	return LOCK_STATE_NOT_HELD;
 }
 
 static struct pin_cookie __lock_pin_lock(struct lockdep_map *lock)
@@ -5537,14 +5538,14 @@ EXPORT_SYMBOL_GPL(lock_release);
 noinstr int lock_is_held_type(const struct lockdep_map *lock, int read)
 {
 	unsigned long flags;
-	int ret = 0;
+	int ret = LOCK_STATE_NOT_HELD;
 
 	/*
 	 * Avoid false negative lockdep_assert_held() and
 	 * lockdep_assert_not_held().
 	 */
 	if (unlikely(!lockdep_enabled()))
-		return -1;
+		return LOCK_STATE_UNKNOWN;
 
 	raw_local_irq_save(flags);
 	check_flags(flags);