swap_info: swap_map of chars not shorts

Halve the vmalloc'ed swap_map array from unsigned shorts to unsigned
chars: it's still very unusual to reach a swap count of 126, and the
next patch allows it to be extended indefinitely.

Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 4 insertions, 4 deletions

diff --git a/include/linux/swap.h b/include/linux/swap.h
index c9d8870892b8..f733deb10748 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -151,9 +151,9 @@ enum {
 
 #define SWAP_CLUSTER_MAX 32
 
-#define SWAP_MAP_MAX    0x7ffe
-#define SWAP_MAP_BAD    0x7fff
-#define SWAP_HAS_CACHE  0x8000          /* There is a swap cache of entry. */
+#define SWAP_MAP_MAX    0x7e
+#define SWAP_MAP_BAD    0x7f
+#define SWAP_HAS_CACHE  0x80            /* There is a swap cache of entry. */
 
 /*
  * The in-memory structure used to track swap areas.
@@ -167,7 +167,7 @@ struct swap_info_struct {
         struct block_device *bdev;
         struct swap_extent first_swap_extent;
         struct swap_extent *curr_swap_extent;
-        unsigned short *swap_map;
+        unsigned char *swap_map;
         unsigned int lowest_bit;
         unsigned int highest_bit;
         unsigned int lowest_alloc;      /* while preparing discard cluster */