From 60a7a88dbb9fc9adcca78a10a3ecf36966b5a45c Mon Sep 17 00:00:00 2001
From: Wei Yang <richard.weiyang@gmail.com>
Date: Wed, 3 May 2017 14:53:51 -0700
Subject: [PATCH] mm/sparse: refine usemap_size() a little

The current implementation calculates usemap_size in two steps:
    * calculate number of bytes to cover these bits
    * calculate number of "unsigned long" to cover these bytes

It would be more clear by:
    * calculate number of "unsigned long" to cover these bits
    * multiple it with sizeof(unsigned long)

This patch refine usemap_size() a little to make it more easy to
understand.

Link: http://lkml.kernel.org/r/20170310043713.96871-1-richard.weiyang@gmail.com
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 mm/sparse.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/mm/sparse.c b/mm/sparse.c
index db6bf3c97ea2c..6903c8fc30850 100644
--- a/mm/sparse.c
+++ b/mm/sparse.c
@@ -248,10 +248,7 @@ static int __meminit sparse_init_one_section(struct mem_section *ms,
 
 unsigned long usemap_size(void)
 {
-	unsigned long size_bytes;
-	size_bytes = roundup(SECTION_BLOCKFLAGS_BITS, 8) / 8;
-	size_bytes = roundup(size_bytes, sizeof(unsigned long));
-	return size_bytes;
+	return BITS_TO_LONGS(SECTION_BLOCKFLAGS_BITS) * sizeof(unsigned long);
 }
 
 #ifdef CONFIG_MEMORY_HOTPLUG
-- 
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