crypto: drivers - Use kmemdup rather than duplicating its implementation

kmemdup is introduced to duplicate a region of memory in a neat way.
Rather than kmalloc/kzalloc + memcpy, which the programmer needs to
write the size twice (sometimes lead to mistakes), kmemdup improves
readability, leads to smaller code and also reduce the chances of mistakes.
Suggestion to use kmemdup rather than using kmalloc/kzalloc + memcpy.

Signed-off-by: Fuqian Huang <[e-mail]>
Reviewed-by: Horia Geantă <[e-mail]>
Acked-by: Michael S. Tsirkin <[e-mail]>
Signed-off-by: Herbert Xu <[e-mail]>

drivers/crypto/caam/caampkc.c

···
 		return ret;
 
 	/* Copy key in DMA zone */
-	rsa_key->e = kzalloc(raw_key.e_sz, GFP_DMA | GFP_KERNEL);
+	rsa_key->e = kmemdup(raw_key.e, raw_key.e_sz, GFP_DMA | GFP_KERNEL);
 	if (!rsa_key->e)
 		goto err;
 
···
 
 	rsa_key->e_sz = raw_key.e_sz;
 	rsa_key->n_sz = raw_key.n_sz;
-
-	memcpy(rsa_key->e, raw_key.e, raw_key.e_sz);
 
 	return 0;
 err:
···
 		return ret;
 
 	/* Copy key in DMA zone */
-	rsa_key->d = kzalloc(raw_key.d_sz, GFP_DMA | GFP_KERNEL);
+	rsa_key->d = kmemdup(raw_key.d, raw_key.d_sz, GFP_DMA | GFP_KERNEL);
 	if (!rsa_key->d)
 		goto err;
 
-	rsa_key->e = kzalloc(raw_key.e_sz, GFP_DMA | GFP_KERNEL);
+	rsa_key->e = kmemdup(raw_key.e, raw_key.e_sz, GFP_DMA | GFP_KERNEL);
 	if (!rsa_key->e)
 		goto err;
 
···
 	rsa_key->d_sz = raw_key.d_sz;
 	rsa_key->e_sz = raw_key.e_sz;
 	rsa_key->n_sz = raw_key.n_sz;
-
-	memcpy(rsa_key->d, raw_key.d, raw_key.d_sz);
-	memcpy(rsa_key->e, raw_key.e, raw_key.e_sz);
 
 	caam_rsa_set_priv_key_form(ctx, &raw_key);
 

drivers/crypto/virtio/virtio_crypto_algs.c

···
 	 * Avoid to do DMA from the stack, switch to using
 	 * dynamically-allocated for the key
 	 */
-	uint8_t *cipher_key = kmalloc(keylen, GFP_ATOMIC);
+	uint8_t *cipher_key = kmemdup(key, keylen, GFP_ATOMIC);
 
 	if (!cipher_key)
 		return -ENOMEM;
-
-	memcpy(cipher_key, key, keylen);
 
 	spin_lock(&vcrypto->ctrl_lock);
 	/* Pad ctrl header */