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>
diff --git a/mm/sparse.c b/mm/sparse.c
index db6bf3c..6903c8f 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