1 files changed, 29 insertions, 22 deletions

diff --git a/kernel/lockdep.c b/kernel/lockdep.c
index f2852a510232..42ba65dff7d9 100644
--- a/kernel/lockdep.c
+++ b/kernel/lockdep.c
@@ -639,6 +639,16 @@ look_up_lock_class(struct lockdep_map *lock, unsigned int subclass)
         }
 #endif
 
+        if (unlikely(subclass >= MAX_LOCKDEP_SUBCLASSES)) {
+                debug_locks_off();
+                printk(KERN_ERR
+                        "BUG: looking up invalid subclass: %u\n", subclass);
+                printk(KERN_ERR
+                        "turning off the locking correctness validator.\n");
+                dump_stack();
+                return NULL;
+        }
+
         /*
          * Static locks do not have their class-keys yet - for them the key
          * is the lock object itself:
@@ -774,7 +784,9 @@ out_unlock_set:
         raw_local_irq_restore(flags);
 
         if (!subclass || force)
-                lock->class_cache = class;
+                lock->class_cache[0] = class;
+        else if (subclass < NR_LOCKDEP_CACHING_CLASSES)
+                lock->class_cache[subclass] = class;
 
         if (DEBUG_LOCKS_WARN_ON(class->subclass != subclass))
                 return NULL;
@@ -2679,7 +2691,11 @@ static int mark_lock(struct task_struct *curr, struct held_lock *this,
 void lockdep_init_map(struct lockdep_map *lock, const char *name,
                       struct lock_class_key *key, int subclass)
 {
-        lock->class_cache = NULL;
+        int i;
+
+        for (i = 0; i < NR_LOCKDEP_CACHING_CLASSES; i++)
+                lock->class_cache[i] = NULL;
+
 #ifdef CONFIG_LOCK_STAT
         lock->cpu = raw_smp_processor_id();
 #endif
@@ -2739,21 +2755,13 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass,
         if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
                 return 0;
 
-        if (unlikely(subclass >= MAX_LOCKDEP_SUBCLASSES)) {
-                debug_locks_off();
-                printk("BUG: MAX_LOCKDEP_SUBCLASSES too low!\n");
-                printk("turning off the locking correctness validator.\n");
-                dump_stack();
-                return 0;
-        }
-
         if (lock->key == &__lockdep_no_validate__)
                 check = 1;
 
-        if (!subclass)
-                class = lock->class_cache;
+        if (subclass < NR_LOCKDEP_CACHING_CLASSES)
+                class = lock->class_cache[subclass];
         /*
-         * Not cached yet or subclass?
+         * Not cached?
          */
         if (unlikely(!class)) {
                 class = register_lock_class(lock, subclass, 0);
@@ -2918,7 +2926,7 @@ static int match_held_lock(struct held_lock *hlock, struct lockdep_map *lock)
                 return 1;
 
         if (hlock->references) {
-                struct lock_class *class = lock->class_cache;
+                struct lock_class *class = lock->class_cache[0];
 
                 if (!class)
                         class = look_up_lock_class(lock, 0);
@@ -3559,7 +3567,12 @@ void lockdep_reset_lock(struct lockdep_map *lock)
                 if (list_empty(head))
                         continue;
                 list_for_each_entry_safe(class, next, head, hash_entry) {
-                        if (unlikely(class == lock->class_cache)) {
+                        int match = 0;
+
+                        for (j = 0; j < NR_LOCKDEP_CACHING_CLASSES; j++)
+                                match |= class == lock->class_cache[j];
+
+                        if (unlikely(match)) {
                                 if (debug_locks_off_graph_unlock())
                                         WARN_ON(1);
                                 goto out_restore;
@@ -3775,7 +3788,7 @@ EXPORT_SYMBOL_GPL(debug_show_all_locks);
  * Careful: only use this function if you are sure that
  * the task cannot run in parallel!
  */
-void __debug_show_held_locks(struct task_struct *task)
+void debug_show_held_locks(struct task_struct *task)
 {
         if (unlikely(!debug_locks)) {
                 printk("INFO: lockdep is turned off.\n");
@@ -3783,12 +3796,6 @@ void __debug_show_held_locks(struct task_struct *task)
         }
         lockdep_print_held_locks(task);
 }
-EXPORT_SYMBOL_GPL(__debug_show_held_locks);
-
-void debug_show_held_locks(struct task_struct *task)
-{
-                __debug_show_held_locks(task);
-}
 EXPORT_SYMBOL_GPL(debug_show_held_locks);
 
 void lockdep_sys_exit(void)