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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>
This commit is contained in:
Wei Yang 2017-05-03 14:53:51 -07:00 committed by Linus Torvalds
parent 8225196341
commit 60a7a88dbb
1 changed files with 1 additions and 4 deletions
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mm/sparse.c
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@ -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