Commit-ID: 70911fdc9576f4eeb3986689a1c9a778a4a4aacb
Gitweb: http://git.kernel.org/tip/70911fdc9576f4eeb3986689a1c9a778a4a4aacb
Author: Byungchul Park <byungchul.park@xxxxxxx>
AuthorDate: Mon, 7 Aug 2017 16:12:50 +0900
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Thu, 10 Aug 2017 12:29:06 +0200
locking/lockdep: Change the meaning of check_prev_add()'s return value
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@xxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: akpm@xxxxxxxxxxxxxxxxxxxx
Cc: boqun.feng@xxxxxxxxx
Cc: kernel-team@xxxxxxx
Cc: kirill@xxxxxxxxxxxxx
Cc: npiggin@xxxxxxxxx
Cc: walken@xxxxxxxxxx
Cc: willy@xxxxxxxxxxxxx
Link: http://lkml.kernel.org/r/1502089981-21272-4-git-send-email-byungchul.park@xxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
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 bdf6b31..7cf02fa 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -1881,7 +1881,7 @@ check_prev_add(struct task_struct *curr, struct held_lock *prev,
if (entry->class == hlock_class(next)) {
if (distance == 1)
entry->distance = 1;
- return 2;
+ return 1;
}
}
@@ -1935,9 +1935,10 @@ check_prev_add(struct task_struct *curr, struct held_lock *prev,
print_lock_name(hlock_class(next));
printk(KERN_CONT "\n");
dump_stack();
- return graph_lock();
+ if (!graph_lock())
+ return 0;
}
- return 1;
+ return 2;
}
/*
--
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