sys_swapon: move setting of error nearer use

Move the setting of the error variable nearer the goto in a few places.

Avoids calling PTR_ERR() if not IS_ERR() in two places, and makes the
error condition more explicit in two other places.

Signed-off-by: Cesar Eduardo Barros <cesarb@cesarb.net>
Tested-by: Eric B Munson <emunson@mgebm.net>
Acked-by: Eric B Munson <emunson@mgebm.net>
Reviewed-by: Jesper Juhl <jj@chaosbits.net>
Reviewed-by: Pekka Enberg <penberg@kernel.org>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
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 b261e55e0b82cfbb5bdacc3f2e08e64e9d1193f3..e4dc94996c5866cafac877ae962d9482d0ba4b9b 100644 (file)
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -1916,14 +1916,14 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
                return PTR_ERR(p);
 
        name = getname(specialfile);
-       error = PTR_ERR(name);
        if (IS_ERR(name)) {
+               error = PTR_ERR(name);
                name = NULL;
                goto bad_swap_2;
        }
        swap_file = filp_open(name, O_RDWR|O_LARGEFILE, 0);
-       error = PTR_ERR(swap_file);
        if (IS_ERR(swap_file)) {
+               error = PTR_ERR(swap_file);
                swap_file = NULL;
                goto bad_swap_2;
        }
@@ -1932,17 +1932,17 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
        mapping = swap_file->f_mapping;
        inode = mapping->host;
 
-       error = -EBUSY;
        for (i = 0; i < nr_swapfiles; i++) {
                struct swap_info_struct *q = swap_info[i];
 
                if (q == p || !q->swap_file)
                        continue;
-               if (mapping == q->swap_file->f_mapping)
+               if (mapping == q->swap_file->f_mapping) {
+                       error = -EBUSY;
                        goto bad_swap;
+               }
        }
 
-       error = -EINVAL;
        if (S_ISBLK(inode->i_mode)) {
                bdev = bdgrab(I_BDEV(inode));
                error = blkdev_get(bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL,
@@ -1966,6 +1966,7 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
                        goto bad_swap;
                }
        } else {
+               error = -EINVAL;
                goto bad_swap;
        }