mm/swapfile.c: make code static

This patch makes the following needlessly global code static:
 - swap_lock
 - nr_swapfiles
 - struct swap_list

Signed-off-by: Adrian Bunk <bunk@kernel.org>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/linux/swap.h

@@ -237,7 +237,6 @@ extern struct page *swapin_readahead(swp_entry_t, gfp_t,
 
 /* linux/mm/swapfile.c */
 extern long total_swap_pages;
-extern unsigned int nr_swapfiles;
 extern void si_swapinfo(struct sysinfo *);
 extern swp_entry_t get_swap_page(void);
 extern swp_entry_t get_swap_page_of_type(int);
@@ -254,8 +253,6 @@ extern int can_share_swap_page(struct page *);
 extern int remove_exclusive_swap_page(struct page *);
 struct backing_dev_info;
 
-extern spinlock_t swap_lock;
-
 /* linux/mm/thrash.c */
 extern struct mm_struct * swap_token_mm;
 extern void grab_swap_token(void);

mm/swapfile.c

@@ -33,8 +33,8 @@
 #include <asm/tlbflush.h>
 #include <linux/swapops.h>
 
-DEFINE_SPINLOCK(swap_lock);
-unsigned int nr_swapfiles;
+static DEFINE_SPINLOCK(swap_lock);
+static unsigned int nr_swapfiles;
 long total_swap_pages;
 static int swap_overflow;
 static int least_priority;
@@ -44,7 +44,7 @@ static const char Unused_file[] = "Unused swap file entry ";
 static const char Bad_offset[] = "Bad swap offset entry ";
 static const char Unused_offset[] = "Unused swap offset entry ";
 
-struct swap_list_t swap_list = {-1, -1};
+static struct swap_list_t swap_list = {-1, -1};
 
 static struct swap_info_struct swap_info[MAX_SWAPFILES];