[PATCH v5 04/13] lockdep: Refactor save_trace()

Byungchul Park
2017-01-18T13:18:03Z

Currently, save_trace() allocates a buffer for saving stack_trace from
the global buffer, and then saves the trace. However, it would be more
useful if a separate buffer can be used. Actually, crossrelease needs
to use separate temporal buffers where to save stack_traces.

Signed-off-by: Byungchul Park <byungchul.park@lge.com>
---
kernel/locking/lockdep.c | 20 ++++++++++++++------
1 file changed, 14 insertions(+), 6 deletions(-)

diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 2081c31..e63ff97 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -392,13 +392,13 @@ static void print_lockdep_off(const char *bug_msg)
#endif
}

-static int save_trace(struct stack_trace *trace)
+static unsigned int __save_trace(struct stack_trace *trace, unsigned long *buf,
+ unsigned long max_nr, int skip)
{
trace->nr_entries = 0;
- trace->max_entries = MAX_STACK_TRACE_ENTRIES - nr_stack_trace_entries;
- trace->entries = stack_trace + nr_stack_trace_entries;
-
- trace->skip = 3;
+ trace->max_entries = max_nr;
+ trace->entries = buf;
+ trace->skip = skip;

save_stack_trace(trace);

@@ -415,7 +415,15 @@ static int save_trace(struct stack_trace *trace)

trace->max_entries = trace->nr_entries;

- nr_stack_trace_entries += trace->nr_entries;
+ return trace->nr_entries;
+}
+
+static int save_trace(struct stack_trace *trace)
+{
+ unsigned long *buf = stack_trace + nr_stack_trace_entries;
+ unsigned long max_nr = MAX_STACK_TRACE_ENTRIES - nr_stack_trace_entries;
+
+ nr_stack_trace_entries += __save_trace(trace, buf, max_nr, 3);

if (nr_stack_trace_entries >= MAX_STACK_TRACE_ENTRIES-1) {
if (!debug_locks_off_graph_unlock())
--
1.9.1