patches/0001-locking-rtmutex-Remove-cruft.patch

From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: Tue, 29 Sep 2020 15:21:17 +0200
Subject: [PATCH 01/22] locking/rtmutex: Remove cruft

Most of this is around since the very beginning. I'm not sure if this
was used while the rtmutex-deadlock-tester was around but today it seems
to only waste memory:
- save_state: No users
- name: Assigned and printed if a dead lock was detected. I'm keeping it
  but want to point out that lockdep has the same information.
- file + line: Printed if ::name was NULL. This is only used for
  in-kernel locks so it ::name shouldn't be NULL and then ::file and
  ::line isn't used.
- magic: Assigned to NULL by rt_mutex_destroy().

Remove members of rt_mutex which are not used.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
 include/linux/rtmutex.h         |    7 ++-----
 kernel/locking/rtmutex-debug.c  |    7 +------
 kernel/locking/rtmutex.c        |    3 ---
 kernel/locking/rtmutex_common.h |    1 -
 4 files changed, 3 insertions(+), 15 deletions(-)

--- a/include/linux/rtmutex.h
+++ b/include/linux/rtmutex.h
@@ -32,10 +32,7 @@ struct rt_mutex {
 	struct rb_root_cached   waiters;
 	struct task_struct	*owner;
 #ifdef CONFIG_DEBUG_RT_MUTEXES
-	int			save_state;
-	const char		*name, *file;
-	int			line;
-	void			*magic;
+	const char		*name;
 #endif
 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 	struct lockdep_map	dep_map;
@@ -60,7 +57,7 @@ struct hrtimer_sleeper;
 
 #ifdef CONFIG_DEBUG_RT_MUTEXES
 # define __DEBUG_RT_MUTEX_INITIALIZER(mutexname) \
-	, .name = #mutexname, .file = __FILE__, .line = __LINE__
+	, .name = #mutexname
 
 # define rt_mutex_init(mutex) \
 do { \
--- a/kernel/locking/rtmutex-debug.c
+++ b/kernel/locking/rtmutex-debug.c
@@ -42,12 +42,7 @@ static void printk_task(struct task_stru
 
 static void printk_lock(struct rt_mutex *lock, int print_owner)
 {
-	if (lock->name)
-		printk(" [%p] {%s}\n",
-			lock, lock->name);
-	else
-		printk(" [%p] {%s:%d}\n",
-			lock, lock->file, lock->line);
+	printk(" [%p] {%s}\n", lock, lock->name);
 
 	if (print_owner && rt_mutex_owner(lock)) {
 		printk(".. ->owner: %p\n", lock->owner);
--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -1655,9 +1655,6 @@ void __sched rt_mutex_futex_unlock(struc
 void rt_mutex_destroy(struct rt_mutex *lock)
 {
 	WARN_ON(rt_mutex_is_locked(lock));
-#ifdef CONFIG_DEBUG_RT_MUTEXES
-	lock->magic = NULL;
-#endif
 }
 EXPORT_SYMBOL_GPL(rt_mutex_destroy);
 
--- a/kernel/locking/rtmutex_common.h
+++ b/kernel/locking/rtmutex_common.h
@@ -30,7 +30,6 @@ struct rt_mutex_waiter {
 	struct task_struct	*task;
 	struct rt_mutex		*lock;
 #ifdef CONFIG_DEBUG_RT_MUTEXES
-	unsigned long		ip;
 	struct pid		*deadlock_task_pid;
 	struct rt_mutex		*deadlock_lock;
 #endif