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>

diff --git a/mm/swapfile.c b/mm/swapfile.c
index 725e56c362deb0ad5b28abef923fabc0fe880d3a..e2adc8eb9317b4490de8f6ff55cc6888b985ab01 100644 (file)
--- 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;