mm/sparse.c: fix ALIGN() without power of 2 in sparse_buffer_alloc()

The size argument passed into sparse_buffer_alloc() has already been
aligned with PAGE_SIZE or PMD_SIZE.

If the size after aligned is not power of 2 (e.g.  0x480000), the
PTR_ALIGN() will return wrong value.  Use roundup to round sparsemap_buf
up to next multiple of size.

Link: http://lkml.kernel.org/r/20190705114826.28586-1-lecopzer.chen@mediatek.comSigned-off-by: Lecopzer Chen <lecopzer.chen@mediatek.com>
Signed-off-by: Mark-PK Tsai <Mark-PK.Tsai@mediatek.com>
Cc: YJ Chiang <yj.chiang@mediatek.com>
Cc: Lecopzer Chen <lecopzer.chen@mediatek.com>
Cc: Pavel Tatashin <pasha.tatashin@oracle.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/sparse.c

@@ -501,7 +501,7 @@ void * __meminit sparse_buffer_alloc(unsigned long size)
 	void *ptr = NULL;
 
 	if (sparsemap_buf) {
-		ptr = PTR_ALIGN(sparsemap_buf, size);
+		ptr = (void *) roundup((unsigned long)sparsemap_buf, size);
 		if (ptr + size > sparsemap_buf_end)
 			ptr = NULL;
 		else {