[PATCH] zsmalloc: turn chain size config option into UL constant

[Sergey Senozhatsky <senozhatsky@chromium.org>]

This fixes

>> mm/zsmalloc.c:122:59: warning: right shift count >= width of type [-Wshift-count-overflow]

and

>> mm/zsmalloc.c:224:28: error: variably modified 'size_class' at file scope
     224 |         struct size_class *size_class[ZS_SIZE_CLASSES];

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
---
 mm/zsmalloc.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
index febfe86d0b1b..290053e648b0 100644
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -133,9 +133,12 @@
 #define MAGIC_VAL_BITS	8
 
 #define MAX(a, b) ((a) >= (b) ? (a) : (b))
+
+#define ZS_MAX_PAGES_PER_ZSPAGE	(_AC(CONFIG_ZSMALLOC_CHAIN_SIZE, UL))
+
 /* ZS_MIN_ALLOC_SIZE must be multiple of ZS_ALIGN */
 #define ZS_MIN_ALLOC_SIZE \
-	MAX(32, (CONFIG_ZSMALLOC_CHAIN_SIZE << PAGE_SHIFT >> OBJ_INDEX_BITS))
+	MAX(32, (ZS_MAX_PAGES_PER_ZSPAGE << PAGE_SHIFT >> OBJ_INDEX_BITS))
 /* each chunk includes extra space to keep handle */
 #define ZS_MAX_ALLOC_SIZE	PAGE_SIZE
 
@@ -1119,7 +1122,7 @@ static struct zspage *alloc_zspage(struct zs_pool *pool,
 					gfp_t gfp)
 {
 	int i;
-	struct page *pages[CONFIG_ZSMALLOC_CHAIN_SIZE];
+	struct page *pages[ZS_MAX_PAGES_PER_ZSPAGE];
 	struct zspage *zspage = cache_alloc_zspage(pool, gfp);
 
 	if (!zspage)
@@ -1986,7 +1989,7 @@ static void replace_sub_page(struct size_class *class, struct zspage *zspage,
 				struct page *newpage, struct page *oldpage)
 {
 	struct page *page;
-	struct page *pages[CONFIG_ZSMALLOC_CHAIN_SIZE] = {NULL, };
+	struct page *pages[ZS_MAX_PAGES_PER_ZSPAGE] = {NULL, };
 	int idx = 0;
 
 	page = get_first_page(zspage);
@@ -2366,7 +2369,7 @@ static int calculate_zspage_chain_size(int class_size)
 	if (is_power_of_2(class_size))
 		return chain_size;
 
-	for (i = 1; i <= CONFIG_ZSMALLOC_CHAIN_SIZE; i++) {
+	for (i = 1; i <= ZS_MAX_PAGES_PER_ZSPAGE; i++) {
 		int waste;
 
 		waste = (i * PAGE_SIZE) % class_size;
-- 
2.39.0.314.g84b9a713c41-goog