commit 1fb00c6cbd8356f43b46322742f3c01c2a1f02da
author Ingo Molnar <mingo@elte.hu> Mon Jun 26 00:24:31 2006 -0700
committer Linus Torvalds <torvalds@g5.osdl.org> Mon Jun 26 09:58:16 2006 -0700
tree d337fb8dca27a719221d9012292e72c55e7267d1
parent 20c5426f8155a89b6df06325f9b278f5052b8c7e

[PATCH] work around ppc64 bootup bug by making mutex-debugging save/restore irqs

It seems ppc64 wants to lock mutexes in early bootup code, with interrupts
disabled, and they expect interrupts to stay disabled, else they crash.

Work around this bug by making mutex debugging variants save/restore irq
flags.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

kernel/mutex.c

diff --git a/kernel/mutex.c b/kernel/mutex.c
index 5449b21..7043db2 100644
--- a/kernel/mutex.c
+++ b/kernel/mutex.c
@@ -125,10 +125,11 @@
 	struct task_struct *task = current;
 	struct mutex_waiter waiter;
 	unsigned int old_val;
+	unsigned long flags;
 
 	debug_mutex_init_waiter(&waiter);
 
-	spin_lock_mutex(&lock->wait_lock);
+	spin_lock_mutex(&lock->wait_lock, flags);
 
 	debug_mutex_add_waiter(lock, &waiter, task->thread_info, ip);
 
@@ -157,7 +158,7 @@
 		if (unlikely(state == TASK_INTERRUPTIBLE &&
 						signal_pending(task))) {
 			mutex_remove_waiter(lock, &waiter, task->thread_info);
-			spin_unlock_mutex(&lock->wait_lock);
+			spin_unlock_mutex(&lock->wait_lock, flags);
 
 			debug_mutex_free_waiter(&waiter);
 			return -EINTR;
@@ -165,9 +166,9 @@
 		__set_task_state(task, state);
 
 		/* didnt get the lock, go to sleep: */
-		spin_unlock_mutex(&lock->wait_lock);
+		spin_unlock_mutex(&lock->wait_lock, flags);
 		schedule();
-		spin_lock_mutex(&lock->wait_lock);
+		spin_lock_mutex(&lock->wait_lock, flags);
 	}
 
 	/* got the lock - rejoice! */
@@ -178,7 +179,7 @@
 	if (likely(list_empty(&lock->wait_list)))
 		atomic_set(&lock->count, 0);
 
-	spin_unlock_mutex(&lock->wait_lock);
+	spin_unlock_mutex(&lock->wait_lock, flags);
 
 	debug_mutex_free_waiter(&waiter);
 
@@ -203,10 +204,11 @@
 __mutex_unlock_slowpath(atomic_t *lock_count __IP_DECL__)
 {
 	struct mutex *lock = container_of(lock_count, struct mutex, count);
+	unsigned long flags;
 
 	DEBUG_WARN_ON(lock->owner != current_thread_info());
 
-	spin_lock_mutex(&lock->wait_lock);
+	spin_lock_mutex(&lock->wait_lock, flags);
 
 	/*
 	 * some architectures leave the lock unlocked in the fastpath failure
@@ -231,7 +233,7 @@
 
 	debug_mutex_clear_owner(lock);
 
-	spin_unlock_mutex(&lock->wait_lock);
+	spin_unlock_mutex(&lock->wait_lock, flags);
 }
 
 /*
@@ -276,9 +278,10 @@
 static inline int __mutex_trylock_slowpath(atomic_t *lock_count)
 {
 	struct mutex *lock = container_of(lock_count, struct mutex, count);
+	unsigned long flags;
 	int prev;
 
-	spin_lock_mutex(&lock->wait_lock);
+	spin_lock_mutex(&lock->wait_lock, flags);
 
 	prev = atomic_xchg(&lock->count, -1);
 	if (likely(prev == 1))
@@ -287,7 +290,7 @@
 	if (likely(list_empty(&lock->wait_list)))
 		atomic_set(&lock->count, 0);
 
-	spin_unlock_mutex(&lock->wait_lock);
+	spin_unlock_mutex(&lock->wait_lock, flags);
 
 	return prev == 1;
 }