mm/swapfile.c: use helper macro K()

Use helper macro K() to improve code readability.  No functional
modification involved.

Link: https://lkml.kernel.org/r/20230804012559.2617515-3-zhangpeng362@huawei.comSigned-off-by: ZhangPeng <zhangpeng362@huawei.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Nanyong Sun <sunnanyong@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/swapfile.c

@@ -46,6 +46,7 @@
 #include <asm/tlbflush.h>
 #include <linux/swapops.h>
 #include <linux/swap_cgroup.h>
+#include "internal.h"
 #include "swap.h"
 
 static bool swap_count_continued(struct swap_info_struct *, pgoff_t,
@@ -2635,8 +2636,8 @@ static int swap_show(struct seq_file *swap, void *v)
 		return 0;
 	}
 
-	bytes = si->pages << (PAGE_SHIFT - 10);
-	inuse = READ_ONCE(si->inuse_pages) << (PAGE_SHIFT - 10);
+	bytes = K(si->pages);
+	inuse = K(READ_ONCE(si->inuse_pages));
 
 	file = si->swap_file;
 	len = seq_file_path(swap, file, " \t\n\\");
@@ -2861,8 +2862,7 @@ static unsigned long read_swap_header(struct swap_info_struct *p,
 	}
 	if (last_page > maxpages) {
 		pr_warn("Truncating oversized swap area, only using %luk out of %luk\n",
-			maxpages << (PAGE_SHIFT - 10),
-			last_page << (PAGE_SHIFT - 10));
+			K(maxpages), K(last_page));
 	}
 	if (maxpages > last_page) {
 		maxpages = last_page + 1;
@@ -3184,8 +3184,8 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
 	enable_swap_info(p, prio, swap_map, cluster_info);
 
 	pr_info("Adding %uk swap on %s.  Priority:%d extents:%d across:%lluk %s%s%s%s\n",
-		p->pages<<(PAGE_SHIFT-10), name->name, p->prio,
-		nr_extents, (unsigned long long)span<<(PAGE_SHIFT-10),
+		K(p->pages), name->name, p->prio, nr_extents,
+		K((unsigned long long)span),
 		(p->flags & SWP_SOLIDSTATE) ? "SS" : "",
 		(p->flags & SWP_DISCARDABLE) ? "D" : "",
 		(p->flags & SWP_AREA_DISCARD) ? "s" : "",