[PATCH] ftrace: Do not copy old hash when resetting.

[Wang Nan <wangnan0@huawei.com>]

If we are going to reset hash, we don't need to duplicate old hash
and remove every entries right after allocation.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@redhat.com>
---
 kernel/trace/ftrace.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 5b372e3..52d6931 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -3471,14 +3471,16 @@ ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len,
 	else
 		orig_hash = &ops->notrace_hash;
 
-	hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
+	if (!reset)
+		hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
+	else
+		hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
+
 	if (!hash) {
 		ret = -ENOMEM;
 		goto out_regex_unlock;
 	}
 
-	if (reset)
-		ftrace_filter_reset(hash);
 	if (buf && !ftrace_match_records(hash, buf, len)) {
 		ret = -EINVAL;
 		goto out_regex_unlock;
-- 
1.8.4