Linux 2.6.21-rc5

[powerpc.git] / kernel / lockdep.c

diff --git a/kernel/lockdep.c b/kernel/lockdep.c
index 2d616f4..7065a68 100644 (file)
--- a/kernel/lockdep.c
+++ b/kernel/lockdep.c
@@ -490,7 +490,7 @@ static void print_lock_dependencies(struct lock_class *class, int depth)
  * Add a new dependency to the head of the list:
  */
 static int add_lock_to_list(struct lock_class *class, struct lock_class *this,
-                           struct list_head *head, unsigned long ip)
+                           struct list_head *head, unsigned long ip, int distance)
 {
        struct lock_list *entry;
        /*
@@ -502,6 +502,7 @@ static int add_lock_to_list(struct lock_class *class, struct lock_class *this,
                return 0;
 
        entry->class = this;
+       entry->distance = distance;
        if (!save_trace(&entry->trace))
                return 0;
 
@@ -906,7 +907,7 @@ check_deadlock(struct task_struct *curr, struct held_lock *next,
  */
 static int
 check_prev_add(struct task_struct *curr, struct held_lock *prev,
-              struct held_lock *next)
+              struct held_lock *next, int distance)
 {
        struct lock_list *entry;
        int ret;
@@ -984,8 +985,11 @@ check_prev_add(struct task_struct *curr, struct held_lock *prev,
         *  L2 added to its dependency list, due to the first chain.)
         */
        list_for_each_entry(entry, &prev->class->locks_after, entry) {
-               if (entry->class == next->class)
+               if (entry->class == next->class) {
+                       if (distance == 1)
+                               entry->distance = 1;
                        return 2;
+               }
        }
 
        /*
@@ -993,12 +997,13 @@ check_prev_add(struct task_struct *curr, struct held_lock *prev,
         * to the previous lock's dependency list:
         */
        ret = add_lock_to_list(prev->class, next->class,
-                              &prev->class->locks_after, next->acquire_ip);
+                              &prev->class->locks_after, next->acquire_ip, distance);
+
        if (!ret)
                return 0;
 
        ret = add_lock_to_list(next->class, prev->class,
-                              &next->class->locks_before, next->acquire_ip);
+                              &next->class->locks_before, next->acquire_ip, distance);
        if (!ret)
                return 0;
 
@@ -1046,13 +1051,14 @@ check_prevs_add(struct task_struct *curr, struct held_lock *next)
                goto out_bug;
 
        for (;;) {
+               int distance = curr->lockdep_depth - depth + 1;
                hlock = curr->held_locks + depth-1;
                /*
                 * Only non-recursive-read entries get new dependencies
                 * added:
                 */
                if (hlock->read != 2) {
-                       if (!check_prev_add(curr, hlock, next))
+                       if (!check_prev_add(curr, hlock, next, distance))
                                return 0;
                        /*
                         * Stop after the first non-trylock entry,
@@ -2222,6 +2228,10 @@ out_calc_hash:
 
        curr->lockdep_depth++;
        check_chain_key(curr);
+#ifdef CONFIG_DEBUG_LOCKDEP
+       if (unlikely(!debug_locks))
+               return 0;
+#endif
        if (unlikely(curr->lockdep_depth >= MAX_LOCK_DEPTH)) {
                debug_locks_off();
                printk("BUG: MAX_LOCK_DEPTH too low!\n");
@@ -2592,7 +2602,7 @@ out_restore:
        raw_local_irq_restore(flags);
 }
 
-void __init lockdep_init(void)
+void lockdep_init(void)
 {
        int i;
 
@@ -2732,6 +2742,10 @@ void debug_show_all_locks(void)
        int count = 10;
        int unlock = 1;
 
+       if (unlikely(!debug_locks)) {
+               printk("INFO: lockdep is turned off.\n");
+               return;
+       }
        printk("\nShowing all locks held in the system:\n");
 
        /*
@@ -2775,8 +2789,11 @@ EXPORT_SYMBOL_GPL(debug_show_all_locks);
 
 void debug_show_held_locks(struct task_struct *task)
 {
+       if (unlikely(!debug_locks)) {
+               printk("INFO: lockdep is turned off.\n");
+               return;
+       }
        lockdep_print_held_locks(task);
 }
 
 EXPORT_SYMBOL_GPL(debug_show_held_locks);
-