[PATCH v8 03/14] lockdep: Change the meaning of check_prev_add()'s return value

Byungchul Park
2017-08-07T07:14:13Z

Firstly, return 1 instead of 2 when 'prev -> next' dependency already
exists. Since the value 2 is not referenced anywhere, just return 1
indicating success in this case.

Secondly, return 2 instead of 1 when successfully added a lock_list
entry with saving stack_trace. With that, a caller can decide whether
to avoid redundant save_trace() on the caller site.

Signed-off-by: Byungchul Park <byungchul.park@lge.com>
---
kernel/locking/lockdep.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 9d16723..b23e930 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -1870,7 +1870,7 @@ static inline void inc_chains(void)
if (entry->class == hlock_class(next)) {
if (distance == 1)
entry->distance = 1;
- return 2;
+ return 1;
}
}

@@ -1910,9 +1910,10 @@ static inline void inc_chains(void)
print_lock_name(hlock_class(next));
printk(KERN_CONT "\n");
dump_stack();
- return graph_lock();
+ if (!graph_lock())
+ return 0;
}
- return 1;
+ return 2;
}

/*
--
1.9.1