lockdep: Implement lockdep_count_*ward_deps by BFS

Implement lockdep_count_{for,back}ward using BFS.

Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1246201486-7308-8-git-send-email-tom.leiming@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/kernel/lockdep.c b/kernel/lockdep.c
index 938dc50..b896f23 100644 (file)
--- a/kernel/lockdep.c
+++ b/kernel/lockdep.c
@@ -1115,61 +1115,59 @@ static noinline int print_bfs_bug(int ret)
        return 0;
 }
 
-unsigned long __lockdep_count_forward_deps(struct lock_class *class,
-                                          unsigned int depth)
+static int noop_count(struct lock_list *entry, void *data)
 {
-       struct lock_list *entry;
-       unsigned long ret = 1;
+       (*(unsigned long *)data)++;
+       return 0;
+}
 
-       if (lockdep_dependency_visit(class, depth))
-               return 0;
+unsigned long __lockdep_count_forward_deps(struct lock_list *this)
+{
+       unsigned long  count = 0;
+       struct lock_list *uninitialized_var(target_entry);
 
-       /*
-        * Recurse this class's dependency list:
-        */
-       list_for_each_entry(entry, &class->locks_after, entry)
-               ret += __lockdep_count_forward_deps(entry->class, depth + 1);
+       __bfs_forwards(this, (void *)&count, noop_count, &target_entry);
 
-       return ret;
+       return count;
 }
-
 unsigned long lockdep_count_forward_deps(struct lock_class *class)
 {
        unsigned long ret, flags;
+       struct lock_list this;
+
+       this.parent = NULL;
+       this.class = class;
 
        local_irq_save(flags);
        __raw_spin_lock(&lockdep_lock);
-       ret = __lockdep_count_forward_deps(class, 0);
+       ret = __lockdep_count_forward_deps(&this);
        __raw_spin_unlock(&lockdep_lock);
        local_irq_restore(flags);
 
        return ret;
 }
 
-unsigned long __lockdep_count_backward_deps(struct lock_class *class,
-                                           unsigned int depth)
+unsigned long __lockdep_count_backward_deps(struct lock_list *this)
 {
-       struct lock_list *entry;
-       unsigned long ret = 1;
+       unsigned long  count = 0;
+       struct lock_list *uninitialized_var(target_entry);
 
-       if (lockdep_dependency_visit(class, depth))
-               return 0;
-       /*
-        * Recurse this class's dependency list:
-        */
-       list_for_each_entry(entry, &class->locks_before, entry)
-               ret += __lockdep_count_backward_deps(entry->class, depth + 1);
+       __bfs_backwards(this, (void *)&count, noop_count, &target_entry);
 
-       return ret;
+       return count;
 }
 
 unsigned long lockdep_count_backward_deps(struct lock_class *class)
 {
        unsigned long ret, flags;
+       struct lock_list this;
+
+       this.parent = NULL;
+       this.class = class;
 
        local_irq_save(flags);
        __raw_spin_lock(&lockdep_lock);
-       ret = __lockdep_count_backward_deps(class, 0);
+       ret = __lockdep_count_backward_deps(&this);
        __raw_spin_unlock(&lockdep_lock);
        local_irq_restore(flags);