mm/swapfile.c: remove unnecessary out label in __swap_duplicate()

When the code went to the out label, it must have p == NULL.  So what out
label really does is redundant if check and return err.  We should Remove
this unnecessary out label because it does not handle resource free and so
on.

Link: https://lkml.kernel.org/r/20201009130337.29698-1-linmiaohe@huawei.comSigned-off-by: NMiaohe Lin <linmiaohe@huawei.com>
Reviewed-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

mm/swapfile.c

@@ -3445,11 +3445,11 @@ static int __swap_duplicate(swp_entry_t entry, unsigned char usage)
 	unsigned long offset;
 	unsigned char count;
 	unsigned char has_cache;
-	int err = -EINVAL;
+	int err;
 
 	p = get_swap_device(entry);
 	if (!p)
-		goto out;
+		return -EINVAL;
 
 	offset = swp_offset(entry);
 	ci = lock_cluster_or_swap_info(p, offset);
@@ -3496,7 +3496,6 @@ static int __swap_duplicate(swp_entry_t entry, unsigned char usage)
 
 unlock_out:
 	unlock_cluster_or_swap_info(p, ci);
-out:
 	if (p)
 		put_swap_device(p);
 	return err;