mm/z3fold: define macro NCHUNKS as TOTAL_CHUNKS - ZHDR_CHUNKS

Patch series "Cleanup and fixup for z3fold".

This series contains cleanups to remove unused function, redefine macro to
improve readability and so on.  Also this fixes several bugs in z3fold,
such as memory leak in z3fold_destroy_pool().  More details can be found
in the respective changelogs.

This patch (of 6):

To improve code readability, we could define macro NCHUNKS as TOTAL_CHUNKS
- ZHDR_CHUNKS.  No functional change intended.

Link: https://lkml.kernel.org/r/20210619093151.1492174-1-linmiaohe@huawei.com
Link: https://lkml.kernel.org/r/20210619093151.1492174-2-linmiaohe@huawei.comSigned-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Vitaly Wool <vitaly.wool@konsulko.com>
Cc: Hillf Danton <hdanton@sina.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/z3fold.c

@@ -62,7 +62,7 @@
 #define ZHDR_SIZE_ALIGNED round_up(sizeof(struct z3fold_header), CHUNK_SIZE)
 #define ZHDR_CHUNKS	(ZHDR_SIZE_ALIGNED >> CHUNK_SHIFT)
 #define TOTAL_CHUNKS	(PAGE_SIZE >> CHUNK_SHIFT)
-#define NCHUNKS		((PAGE_SIZE - ZHDR_SIZE_ALIGNED) >> CHUNK_SHIFT)
+#define NCHUNKS		(TOTAL_CHUNKS - ZHDR_CHUNKS)
 
 #define BUDDY_MASK	(0x3)
 #define BUDDY_SHIFT	2