The next_page is only used to forward page in case target is in second
half range.  Move forward page directly to remove unnecessary next_page.
Link: https://lkml.kernel.org/r/20230927103514.98281-3-shikemeng@huaweicloud.com
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Acked-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
                                   int migratetype)
 {
        unsigned long size = 1 << high;
-       struct page *current_buddy, *next_page;
+       struct page *current_buddy;
 
        while (high > low) {
                high--;
                size >>= 1;
 
                if (target >= &page[size]) {
-                       next_page = page + size;
                        current_buddy = page;
+                       page = page + size;
                } else {
-                       next_page = page;
                        current_buddy = page + size;
                }
-               page = next_page;
 
                if (set_page_guard(zone, current_buddy, high, migratetype))
                        continue;