[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, 5 insertions, 20 deletions

diff --git a/kernel/mutex-debug.h b/kernel/mutex-debug.h
index fd384050acb1..a5196c36a5fd 100644
--- a/kernel/mutex-debug.h
+++ b/kernel/mutex-debug.h
@@ -46,21 +46,6 @@ extern void mutex_remove_waiter(struct mutex *lock, struct mutex_waiter *waiter,
 extern void debug_mutex_unlock(struct mutex *lock);
 extern void debug_mutex_init(struct mutex *lock, const char *name);
 
-#define debug_spin_lock(lock)                           \
-        do {                                            \
-                local_irq_disable();                    \
-                if (debug_mutex_on)                     \
-                        spin_lock(lock);                \
-        } while (0)
-
-#define debug_spin_unlock(lock)                         \
-        do {                                            \
-                if (debug_mutex_on)                     \
-                        spin_unlock(lock);              \
-                local_irq_enable();                     \
-                preempt_check_resched();                \
-        } while (0)
-
 #define debug_spin_lock_save(lock, flags)               \
         do {                                            \
                 local_irq_save(flags);                  \
@@ -68,7 +53,7 @@ extern void debug_mutex_init(struct mutex *lock, const char *name);
                         spin_lock(lock);                \
         } while (0)
 
-#define debug_spin_lock_restore(lock, flags)            \
+#define debug_spin_unlock_restore(lock, flags)          \
         do {                                            \
                 if (debug_mutex_on)                     \
                         spin_unlock(lock);              \
@@ -76,20 +61,20 @@ extern void debug_mutex_init(struct mutex *lock, const char *name);
                 preempt_check_resched();                \
         } while (0)
 
-#define spin_lock_mutex(lock)                           \
+#define spin_lock_mutex(lock, flags)                    \
         do {                                            \
                 struct mutex *l = container_of(lock, struct mutex, wait_lock); \
                                                         \
                 DEBUG_WARN_ON(in_interrupt());          \
-                debug_spin_lock(&debug_mutex_lock);     \
+                debug_spin_lock_save(&debug_mutex_lock, flags); \
                 spin_lock(lock);                        \
                 DEBUG_WARN_ON(l->magic != l);           \
         } while (0)
 
-#define spin_unlock_mutex(lock)                         \
+#define spin_unlock_mutex(lock, flags)                  \
         do {                                            \
                 spin_unlock(lock);                      \
-                debug_spin_unlock(&debug_mutex_lock);   \
+                debug_spin_unlock_restore(&debug_mutex_lock, flags);    \
         } while (0)
 
 #define DEBUG_OFF()                                     \