ceph: Use kmemdup rather than duplicating its implementation

Use kmemdup rather than duplicating its implementation

The semantic patch that makes this change is available
in scripts/coccinelle/api/memdup.cocci.
Signed-off-by: NThomas Meyer <thomas@m3y3r.de>
Signed-off-by: NSage Weil <sage@newdream.net>

net/ceph/crypto.c

@@ -15,10 +15,9 @@ int ceph_crypto_key_clone(struct ceph_crypto_key *dst,
 			  const struct ceph_crypto_key *src)
 {
 	memcpy(dst, src, sizeof(struct ceph_crypto_key));
-	dst->key = kmalloc(src->len, GFP_NOFS);
+	dst->key = kmemdup(src->key, src->len, GFP_NOFS);
 	if (!dst->key)
 		return -ENOMEM;
-	memcpy(dst->key, src->key, src->len);
 	return 0;
 }