smb: server: inline smb_direct_create_header() into smb_direct_post_send_data()

The point is that ib_dma_map_single() is done first, but
the 'Fill in the packet header' will be done after
smbdirect_map_sges_from_iter().

This will simplify further changes in order to
share common code with the client.

Cc: Namjae Jeon <linkinjeon@kernel.org>
Cc: Steve French <smfrench@gmail.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: linux-cifs@vger.kernel.org
Cc: samba-technical@lists.samba.org
Signed-off-by: Stefan Metzmacher <metze@samba.org>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>

Author: metze-samba

fs/smb/server/transport_rdma.c

@@ -764,72 +764,6 @@ static int wait_for_send_credits(struct smbdirect_socket *sc,
 						 1);
 }
 
-static int smb_direct_create_header(struct smbdirect_socket *sc,
-				    int size, int remaining_data_length,
-				    int new_credits,
-				    struct smbdirect_send_io **sendmsg_out)
-{
-	struct smbdirect_socket_parameters *sp = &sc->parameters;
-	struct smbdirect_send_io *sendmsg;
-	struct smbdirect_data_transfer *packet;
-	int header_length;
-	int ret;
-
-	sendmsg = smbdirect_connection_alloc_send_io(sc);
-	if (IS_ERR(sendmsg))
-		return PTR_ERR(sendmsg);
-
-	/* Fill in the packet header */
-	packet = (struct smbdirect_data_transfer *)sendmsg->packet;
-	packet->credits_requested = cpu_to_le16(sp->send_credit_target);
-	packet->credits_granted = cpu_to_le16(new_credits);
-
-	packet->flags = 0;
-	if (smbdirect_connection_request_keep_alive(sc))
-		packet->flags |= cpu_to_le16(SMBDIRECT_FLAG_RESPONSE_REQUESTED);
-
-	packet->reserved = 0;
-	if (!size)
-		packet->data_offset = 0;
-	else
-		packet->data_offset = cpu_to_le32(24);
-	packet->data_length = cpu_to_le32(size);
-	packet->remaining_data_length = cpu_to_le32(remaining_data_length);
-	packet->padding = 0;
-
-	ksmbd_debug(RDMA,
-		    "credits_requested=%d credits_granted=%d data_offset=%d data_length=%d remaining_data_length=%d\n",
-		    le16_to_cpu(packet->credits_requested),
-		    le16_to_cpu(packet->credits_granted),
-		    le32_to_cpu(packet->data_offset),
-		    le32_to_cpu(packet->data_length),
-		    le32_to_cpu(packet->remaining_data_length));
-
-	/* Map the packet to DMA */
-	header_length = sizeof(struct smbdirect_data_transfer);
-	/* If this is a packet without payload, don't send padding */
-	if (!size)
-		header_length =
-			offsetof(struct smbdirect_data_transfer, padding);
-
-	sendmsg->sge[0].addr = ib_dma_map_single(sc->ib.dev,
-						 (void *)packet,
-						 header_length,
-						 DMA_TO_DEVICE);
-	ret = ib_dma_mapping_error(sc->ib.dev, sendmsg->sge[0].addr);
-	if (ret) {
-		smbdirect_connection_free_send_io(sendmsg);
-		return ret;
-	}
-
-	sendmsg->num_sge = 1;
-	sendmsg->sge[0].length = header_length;
-	sendmsg->sge[0].lkey = sc->ib.pd->local_dma_lkey;
-
-	*sendmsg_out = sendmsg;
-	return 0;
-}
-
 static int post_sendmsg(struct smbdirect_socket *sc,
 			struct smbdirect_send_batch *send_ctx,
 			struct smbdirect_send_io *msg)
@@ -873,13 +807,23 @@ static int smb_direct_post_send_data(struct smbdirect_socket *sc,
 				     struct iov_iter *iter,
 				     size_t *_remaining_data_length)
 {
+	const struct smbdirect_socket_parameters *sp = &sc->parameters;
 	int ret;
 	struct smbdirect_send_io *msg;
+	struct smbdirect_data_transfer *packet;
+	size_t header_length;
 	u32 remaining_data_length = 0;
 	u32 data_length = 0;
 	struct smbdirect_send_batch _send_ctx;
 	u16 new_credits;
 
+	if (iter) {
+		header_length = sizeof(struct smbdirect_data_transfer);
+	} else {
+		/* If this is a packet without payload, don't send padding */
+		header_length = offsetof(struct smbdirect_data_transfer, padding);
+	}
+
 	if (!send_ctx) {
 		smb_direct_send_ctx_init(&_send_ctx, false, 0);
 		send_ctx = &_send_ctx;
@@ -922,10 +866,24 @@ static int smb_direct_post_send_data(struct smbdirect_socket *sc,
 		remaining_data_length = *_remaining_data_length;
 	}
 
-	ret = smb_direct_create_header(sc, data_length, remaining_data_length,
-				       new_credits, &msg);
+	msg = smbdirect_connection_alloc_send_io(sc);
+	if (IS_ERR(msg)) {
+		ret = PTR_ERR(msg);
+		goto alloc_failed;
+	}
+
+	/* Map the packet to DMA */
+	msg->sge[0].addr = ib_dma_map_single(sc->ib.dev,
+					     msg->packet,
+					     header_length,
+					     DMA_TO_DEVICE);
+	ret = ib_dma_mapping_error(sc->ib.dev, msg->sge[0].addr);
 	if (ret)
-		goto header_failed;
+		goto err;
+
+	msg->sge[0].length = header_length;
+	msg->sge[0].lkey = sc->ib.pd->local_dma_lkey;
+	msg->num_sge = 1;
 
 	if (iter) {
 		struct smbdirect_map_sges extract = {
@@ -947,6 +905,34 @@ static int smb_direct_post_send_data(struct smbdirect_socket *sc,
 		msg->num_sge = extract.num_sge;
 	}
 
+	/* Fill in the packet header */
+	packet = (struct smbdirect_data_transfer *)msg->packet;
+	packet->credits_requested = cpu_to_le16(sp->send_credit_target);
+	new_credits = smbdirect_connection_grant_recv_credits(sc);
+	packet->credits_granted = cpu_to_le16(new_credits);
+
+	packet->flags = 0;
+	if (smbdirect_connection_request_keep_alive(sc))
+		packet->flags |= cpu_to_le16(SMBDIRECT_FLAG_RESPONSE_REQUESTED);
+
+	packet->reserved = 0;
+	if (!data_length)
+		packet->data_offset = 0;
+	else
+		packet->data_offset = cpu_to_le32(24);
+	packet->data_length = cpu_to_le32(data_length);
+	packet->remaining_data_length = cpu_to_le32(remaining_data_length);
+	packet->padding = 0;
+
+	ksmbd_debug(RDMA,
+		    "credits_req=%u credits_granted=%u flags=0x%x ofs=%u len=%u remaining=%u\n",
+		    le16_to_cpu(packet->credits_requested),
+		    le16_to_cpu(packet->credits_granted),
+		    le16_to_cpu(packet->flags),
+		    le32_to_cpu(packet->data_offset),
+		    le32_to_cpu(packet->data_length),
+		    le32_to_cpu(packet->remaining_data_length));
+
 	ret = post_sendmsg(sc, send_ctx, msg);
 	if (ret)
 		goto err;
@@ -966,7 +952,7 @@ static int smb_direct_post_send_data(struct smbdirect_socket *sc,
 err:
 	smbdirect_connection_free_send_io(msg);
 flush_failed:
-header_failed:
+alloc_failed:
 	atomic_inc(&sc->send_io.credits.count);
 credit_failed:
 	atomic_inc(&sc->send_io.lcredits.count);