From: Wei Yang <richard.weiyang@linux.alibaba.com>
Date: Mon, 31 Aug 2020 03:11:00 +0000 (+0800)
Subject: ftrace: Use fls() to get the bits for dup_hash()
X-Git-Tag: iomap-folio-5.17-old~2952^2~19
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=59e65b3358f44d4d0134eca3b6c269f359f21cd5;p=users%2Fwilly%2Flinux.git

ftrace: Use fls() to get the bits for dup_hash()

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

Link: https://lkml.kernel.org/r/20200831031104.23322-3-richard.weiyang@linux.alibaba.com

Signed-off-by: Wei Yang <richard.weiyang@linux.alibaba.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 123d520b9261..5633d37d8806 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)