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Subject[tip:core/locking] lockdep: Implement lockdep_count_*ward_deps by BFS
Commit-ID:  ef681026ff85c49b7399ceec3eb62bbbcce605e8
Gitweb: http://git.kernel.org/tip/ef681026ff85c49b7399ceec3eb62bbbcce605e8
Author: Ming Lei <tom.leiming@gmail.com>
AuthorDate: Thu, 16 Jul 2009 15:44:29 +0200
Committer: Peter Zijlstra <a.p.zijlstra@chello.nl>
CommitDate: Fri, 24 Jul 2009 10:49:56 +0200

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>


---
kernel/lockdep.c | 52 +++++++++++++++++++++++++---------------------------
1 files changed, 25 insertions(+), 27 deletions(-)

diff --git a/kernel/lockdep.c b/kernel/lockdep.c
index 938dc50..b896f23 100644
--- 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);


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