swapfile: swapon needs larger size type

sys_swapon()'s swapfilesize (better renamed swapfilepages) is declared as
an int, but should be an unsigned long like the maxpages it's compared
against: on 64-bit (with 4kB pages) a swapfile of 2^44 bytes was rejected
with "Swap area shorter than signature indicates".

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 3 insertions, 3 deletions

diff --git a/mm/swapfile.c b/mm/swapfile.c
index 725e56c362d..e2adc8eb931 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -1461,7 +1461,7 @@ asmlinkage long sys_swapon(const char __user * specialfile, int swap_flags)
         int nr_extents = 0;
         sector_t span;
         unsigned long maxpages = 1;
-        int swapfilesize;
+        unsigned long swapfilepages;
         unsigned short *swap_map = NULL;
         struct page *page = NULL;
         struct inode *inode = NULL;
@@ -1539,7 +1539,7 @@ asmlinkage long sys_swapon(const char __user * specialfile, int swap_flags)
                 goto bad_swap;
         }
 
-        swapfilesize = i_size_read(inode) >> PAGE_SHIFT;
+        swapfilepages = i_size_read(inode) >> PAGE_SHIFT;
 
         /*
          * Read the swap header.
@@ -1616,7 +1616,7 @@ asmlinkage long sys_swapon(const char __user * specialfile, int swap_flags)
                 error = -EINVAL;
                 if (!maxpages)
                         goto bad_swap;
-                if (swapfilesize && maxpages > swapfilesize) {
+                if (swapfilepages && maxpages > swapfilepages) {
                         printk(KERN_WARNING
                                "Swap area shorter than signature indicates\n");
                         goto bad_swap;