tls: rx: use async as an in-out argument

Propagating EINPROGRESS thru multiple layers of functions is
error prone. Use darg->async as an in/out argument, like we
use darg->zc today. On input it tells the code if async is
allowed, on output if it took place.
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/tls/tls_sw.c

@@ -227,7 +227,7 @@ static int tls_do_decryption(struct sock *sk,
 			     char *iv_recv,
 			     size_t data_len,
 			     struct aead_request *aead_req,
-			     bool async)
+			     struct tls_decrypt_arg *darg)
 {
 	struct tls_context *tls_ctx = tls_get_ctx(sk);
 	struct tls_prot_info *prot = &tls_ctx->prot_info;
@@ -240,7 +240,7 @@ static int tls_do_decryption(struct sock *sk,
 			       data_len + prot->tag_size,
 			       (u8 *)iv_recv);
 
-	if (async) {
+	if (darg->async) {
 		/* Using skb->sk to push sk through to crypto async callback
 		 * handler. This allows propagating errors up to the socket
 		 * if needed. It _must_ be cleared in the async handler
@@ -260,11 +260,13 @@ static int tls_do_decryption(struct sock *sk,
 
 	ret = crypto_aead_decrypt(aead_req);
 	if (ret == -EINPROGRESS) {
-		if (async)
-			return ret;
+		if (darg->async)
+			return 0;
 
 		ret = crypto_wait_req(ret, &ctx->async_wait);
 	}
+	darg->async = false;
+
 	if (ret == -EBADMSG)
 		TLS_INC_STATS(sock_net(sk), LINUX_MIB_TLSDECRYPTERROR);
 
@@ -1536,9 +1538,9 @@ static int decrypt_internal(struct sock *sk, struct sk_buff *skb,
 
 	/* Prepare and submit AEAD request */
 	err = tls_do_decryption(sk, skb, sgin, sgout, iv,
-				data_len, aead_req, darg->async);
-	if (err == -EINPROGRESS)
-		return err;
+				data_len, aead_req, darg);
+	if (darg->async)
+		return 0;
 
 	/* Release the pages in case iov was mapped to pages */
 	for (; pages > 0; pages--)
@@ -1575,11 +1577,10 @@ static int decrypt_skb_update(struct sock *sk, struct sk_buff *skb,
 	}
 
 	err = decrypt_internal(sk, skb, dest, NULL, darg);
-	if (err < 0) {
-		if (err == -EINPROGRESS)
-			tls_advance_record_sn(sk, prot, &tls_ctx->rx);
+	if (err < 0)
 		return err;
-	}
+	if (darg->async)
+		goto decrypt_next;
 
 decrypt_done:
 	pad = padding_length(prot, skb);
@@ -1589,8 +1590,9 @@ static int decrypt_skb_update(struct sock *sk, struct sk_buff *skb,
 	rxm->full_len -= pad;
 	rxm->offset += prot->prepend_size;
 	rxm->full_len -= prot->overhead_size;
-	tls_advance_record_sn(sk, prot, &tls_ctx->rx);
 	tlm->decrypted = 1;
+decrypt_next:
+	tls_advance_record_sn(sk, prot, &tls_ctx->rx);
 
 	return 0;
 }
@@ -1796,13 +1798,12 @@ int tls_sw_recvmsg(struct sock *sk,
 			darg.async = false;
 
 		err = decrypt_skb_update(sk, skb, &msg->msg_iter, &darg);
-		if (err < 0 && err != -EINPROGRESS) {
+		if (err < 0) {
 			tls_err_abort(sk, -EBADMSG);
 			goto recv_end;
 		}
 
-		if (err == -EINPROGRESS)
-			async = true;
+		async |= darg.async;
 
 		/* If the type of records being processed is not known yet,
 		 * set it to record type just dequeued. If it is already known,