[PATCH 2/6] ftrace: use fls() to get the bits for dup_hash()

From: Wei Yang
Date: Sun Aug 30 2020 - 23:11:37 EST


The effect here is to get the number of bits, lets use fls() to do
this job.

Signed-off-by: Wei Yang <richard.weiyang@xxxxxxxxxxxxxxxxx>
---
kernel/trace/ftrace.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 12cb535769bc..9021e16fa079 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -1370,8 +1370,9 @@ static struct ftrace_hash *dup_hash(struct ftrace_hash *src, int size)
/*
* Make the hash size about 1/2 the # found
*/
- for (size /= 2; size; size >>= 1)
- bits++;
+ bits = fls(size);
+ if (bits)
+ bits--;

/* Don't allocate too much */
if (bits > FTRACE_HASH_MAX_BITS)
--
2.20.1 (Apple Git-117)