sys_swapon: do only cleanup in the cleanup blocks

The only way error is 0 in the cleanup blocks is when the function is
returning successfully. In this case, the cleanup blocks were setting
S_SWAPFILE in the S_ISREG case. But this is not a cleanup.

Move the setting of S_SWAPFILE to just before the "goto out;" to make
this more clear. At this point, we do not need to test for inode because
it will never be NULL.

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>

mm/swapfile.c

@@ -2136,6 +2136,8 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
 	atomic_inc(&proc_poll_event);
 	wake_up_interruptible(&proc_poll_wait);
 
+	if (S_ISREG(inode->i_mode))
+		inode->i_flags |= S_SWAPFILE;
 	error = 0;
 	goto out;
 bad_swap:
@@ -2163,11 +2165,8 @@ out:
 	}
 	if (name)
 		putname(name);
-	if (inode && S_ISREG(inode->i_mode)) {
-		if (!error)
-			inode->i_flags |= S_SWAPFILE;
+	if (inode && S_ISREG(inode->i_mode))
 		mutex_unlock(&inode->i_mutex);
-	}
 	return error;
 }