crypto: algif_aead - Only wake up when ctx->more is zero

AEAD does not support partial requests so we must not wake up
while ctx->more is set.  In order to distinguish between the
case of no data sent yet and a zero-length request, a new init
flag has been added to ctx.

SKCIPHER has also been modified to ensure that at least a block
of data is available if there is more data to come.

Fixes: 2d97591ef4 ("crypto: af_alg - consolidation of...")
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto/algif_skcipher.c

@@ -61,8 +61,8 @@ static int _skcipher_recvmsg(struct socket *sock, struct msghdr *msg,
 	int err = 0;
 	size_t len = 0;
 
-	if (!ctx->used) {
-		err = af_alg_wait_for_data(sk, flags);
+	if (!ctx->init || (ctx->more && ctx->used < bs)) {
+		err = af_alg_wait_for_data(sk, flags, bs);
 		if (err)
 			return err;
 	}