crypto: aead - Add skcipher null for IV generators

This patch adds an skcipher null object alongside the existing
null blkcipher so that IV generators using it can switch over
to skcipher.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto/aead.c

@@ -294,10 +294,15 @@ int aead_init_geniv(struct crypto_aead *aead)
 	if (err)
 		goto out;
 
+	ctx->sknull = crypto_get_default_null_skcipher2();
+	err = PTR_ERR(ctx->sknull);
+	if (IS_ERR(ctx->sknull))
+		goto out;
+
 	ctx->null = crypto_get_default_null_skcipher();
 	err = PTR_ERR(ctx->null);
 	if (IS_ERR(ctx->null))
-		goto out;
+		goto drop_sknull;
 
 	child = crypto_spawn_aead(aead_instance_ctx(inst));
 	err = PTR_ERR(child);
@@ -315,6 +320,8 @@ out:
 
 drop_null:
 	crypto_put_default_null_skcipher();
+drop_sknull:
+	crypto_put_default_null_skcipher2();
 	goto out;
 }
 EXPORT_SYMBOL_GPL(aead_init_geniv);
@@ -325,6 +332,7 @@ void aead_exit_geniv(struct crypto_aead *tfm)
 
 	crypto_free_aead(ctx->child);
 	crypto_put_default_null_skcipher();
+	crypto_put_default_null_skcipher2();
 }
 EXPORT_SYMBOL_GPL(aead_exit_geniv);