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Commit 6720a305 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

locking: avoid passing around 'thread_info' in mutex debugging code 



None of the code actually wants a thread_info, it all wants a
task_struct, and it's just converting back and forth between the two
("ti->task" to get the task_struct from the thread_info, and
"task_thread_info(task)" to go the other way).

No semantic change.

Acked-by: default avatarPeter Zijlstra <peterz@infradead.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent f9020d17

kernel/locking/mutex-debug.c

+6 −6
Original line number Diff line number Diff line
@@ -49,21 +49,21 @@ void debug_mutex_free_waiter(struct mutex_waiter *waiter) 
}



void debug_mutex_add_waiter(struct mutex *lock, struct mutex_waiter *waiter,

			    struct thread_info *ti)

			    struct task_struct *task)

{

	SMP_DEBUG_LOCKS_WARN_ON(!spin_is_locked(&lock->wait_lock));



	/* Mark the current thread as blocked on the lock: */

	ti->task->blocked_on = waiter;

	task->blocked_on = waiter;

}



void mutex_remove_waiter(struct mutex *lock, struct mutex_waiter *waiter,

			 struct thread_info *ti)

			 struct task_struct *task)

{

	DEBUG_LOCKS_WARN_ON(list_empty(&waiter->list));

	DEBUG_LOCKS_WARN_ON(waiter->task != ti->task);

	DEBUG_LOCKS_WARN_ON(ti->task->blocked_on != waiter);

	ti->task->blocked_on = NULL;

	DEBUG_LOCKS_WARN_ON(waiter->task != task);

	DEBUG_LOCKS_WARN_ON(task->blocked_on != waiter);

	task->blocked_on = NULL;



	list_del_init(&waiter->list);

	waiter->task = NULL;

kernel/locking/mutex-debug.h

+2 −2
Original line number Diff line number Diff line
@@ -20,9 +20,9 @@ extern void debug_mutex_wake_waiter(struct mutex *lock, 
extern void debug_mutex_free_waiter(struct mutex_waiter *waiter);

extern void debug_mutex_add_waiter(struct mutex *lock,

				   struct mutex_waiter *waiter,

				   struct thread_info *ti);

				   struct task_struct *task);

extern void mutex_remove_waiter(struct mutex *lock, struct mutex_waiter *waiter,

				struct thread_info *ti);

				struct task_struct *task);

extern void debug_mutex_unlock(struct mutex *lock);

extern void debug_mutex_init(struct mutex *lock, const char *name,

			     struct lock_class_key *key);

kernel/locking/mutex.c

+3 −3
Original line number Diff line number Diff line
@@ -537,7 +537,7 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass, 
		goto skip_wait;



	debug_mutex_lock_common(lock, &waiter);

	debug_mutex_add_waiter(lock, &waiter, task_thread_info(task));

	debug_mutex_add_waiter(lock, &waiter, task);



	/* add waiting tasks to the end of the waitqueue (FIFO): */

	list_add_tail(&waiter.list, &lock->wait_list);
@@ -584,7 +584,7 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass, 
	}

	__set_task_state(task, TASK_RUNNING);



	mutex_remove_waiter(lock, &waiter, current_thread_info());

	mutex_remove_waiter(lock, &waiter, task);

	/* set it to 0 if there are no waiters left: */

	if (likely(list_empty(&lock->wait_list)))

		atomic_set(&lock->count, 0);
@@ -605,7 +605,7 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass, 
	return 0;



err:

	mutex_remove_waiter(lock, &waiter, task_thread_info(task));

	mutex_remove_waiter(lock, &waiter, task);

	spin_unlock_mutex(&lock->wait_lock, flags);

	debug_mutex_free_waiter(&waiter);

	mutex_release(&lock->dep_map, 1, ip);

kernel/locking/mutex.h

+1 −1
Original line number Diff line number Diff line
@@ -13,7 +13,7 @@ 
		do { spin_lock(lock); (void)(flags); } while (0)

#define spin_unlock_mutex(lock, flags) \

		do { spin_unlock(lock); (void)(flags); } while (0)

#define mutex_remove_waiter(lock, waiter, ti) \

#define mutex_remove_waiter(lock, waiter, task) \

		__list_del((waiter)->list.prev, (waiter)->list.next)



#ifdef CONFIG_MUTEX_SPIN_ON_OWNER