[PATCH v2] ftrace: simplify ftrace hash lookup code

From: Changbin Du
Date: Sun Sep 08 2019 - 20:32:53 EST


Function ftrace_lookup_ip() will check empty hash table. So we don't
need extra check outside.

Signed-off-by: Changbin Du <changbin.du@xxxxxxxxx>

---
v2: fix incorrect code remove.
---
kernel/trace/ftrace.c | 9 ++-------
1 file changed, 2 insertions(+), 7 deletions(-)

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index f9821a3374e9..92aab854d3b1 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -1463,8 +1463,7 @@ static bool hash_contains_ip(unsigned long ip,
*/
return (ftrace_hash_empty(hash->filter_hash) ||
__ftrace_lookup_ip(hash->filter_hash, ip)) &&
- (ftrace_hash_empty(hash->notrace_hash) ||
- !__ftrace_lookup_ip(hash->notrace_hash, ip));
+ !ftrace_lookup_ip(hash->notrace_hash, ip);
}

/*
@@ -6036,11 +6035,7 @@ clear_func_from_hash(struct ftrace_init_func *func, struct ftrace_hash *hash)
{
struct ftrace_func_entry *entry;

- if (ftrace_hash_empty(hash))
- return;
-
- entry = __ftrace_lookup_ip(hash, func->ip);
-
+ entry = ftrace_lookup_ip(hash, func->ip);
/*
* Do not allow this rec to match again.
* Yeah, it may waste some memory, but will be removed
--
2.20.1