sys_swapon: use a single error label

sys_swapon currently has two error labels, bad_swap and bad_swap_2.
bad_swap does the same as bad_swap_2 plus destroy_swap_extents() and
swap_cgroup_swapoff(); both are noops in the places where bad_swap_2 is
jumped to. With a single extra test for inode (matching the one in the
S_ISREG case below), all the error paths in the function can go to
bad_swap.

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: 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>

1 files changed, 3 insertions, 4 deletions

diff --git a/mm/swapfile.c b/mm/swapfile.c
index e356e5e70313..14590775212d 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -1918,13 +1918,13 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
         if (IS_ERR(name)) {
                 error = PTR_ERR(name);
                 name = NULL;
-                goto bad_swap_2;
+                goto bad_swap;
         }
         swap_file = filp_open(name, O_RDWR|O_LARGEFILE, 0);
         if (IS_ERR(swap_file)) {
                 error = PTR_ERR(swap_file);
                 swap_file = NULL;
-                goto bad_swap_2;
+                goto bad_swap;
         }
 
         p->swap_file = swap_file;
@@ -2141,13 +2141,12 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
         error = 0;
         goto out;
 bad_swap:
-        if (S_ISBLK(inode->i_mode) && p->bdev) {
+        if (inode && S_ISBLK(inode->i_mode) && p->bdev) {
                 set_blocksize(p->bdev, p->old_block_size);
                 blkdev_put(p->bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL);
         }
         destroy_swap_extents(p);
         swap_cgroup_swapoff(p->type);
-bad_swap_2:
         spin_lock(&swap_lock);
         p->swap_file = NULL;
         p->flags = 0;