[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>

1 files changed, 12 insertions, 9 deletions

diff --git a/kernel/mutex.c b/kernel/mutex.c
index 5449b210d9ed..7043db21bbce 100644
--- a/kernel/mutex.c
+++ b/kernel/mutex.c
@@ -125,10 +125,11 @@ __mutex_lock_common(struct mutex *lock, long state __IP_DECL__)
         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 @@ __mutex_lock_common(struct mutex *lock, long state __IP_DECL__)
                 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 @@ __mutex_lock_common(struct mutex *lock, long state __IP_DECL__)
                 __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 @@ __mutex_lock_common(struct mutex *lock, long state __IP_DECL__)
         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 @@ static fastcall noinline void
 __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 @@ __mutex_unlock_slowpath(atomic_t *lock_count __IP_DECL__)
 
         debug_mutex_clear_owner(lock);
 
-        spin_unlock_mutex(&lock->wait_lock);
+        spin_unlock_mutex(&lock->wait_lock, flags);
 }
 
 /*
@@ -276,9 +278,10 @@ __mutex_lock_interruptible_slowpath(atomic_t *lock_count __IP_DECL__)
 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 @@ static inline int __mutex_trylock_slowpath(atomic_t *lock_count)
         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;
 }