From: Sagi Grimberg <redacted>

This patch implements the NVMe over TCP host driver. It can be used to
connect to remote NVMe over Fabrics subsystems over good old TCP/IP.

The driver implements the TP 8000 of how nvme over fabrics capsules and
data are encapsulated in nvme-tcp pdus and exchaged on top of a TCP byte
stream. nvme-tcp header and data digest are supported as well.

To connect to all NVMe over Fabrics controllers reachable on a given taget
port over TCP use the following command:

	nvme connect-all -t tcp -a $IPADDR

This requires the latest version of nvme-cli with TCP support.

Signed-off-by: Sagi Grimberg <redacted>
Signed-off-by: Roy Shterman <redacted>
Signed-off-by: Solganik Alexander <redacted>
---
 drivers/nvme/host/Kconfig  |   15 +
 drivers/nvme/host/Makefile |    3 +
 drivers/nvme/host/tcp.c    | 2306 ++++++++++++++++++++++++++++++++++++
 3 files changed, 2324 insertions(+)
 create mode 100644 drivers/nvme/host/tcp.c

diff --git a/drivers/nvme/host/Kconfig b/drivers/nvme/host/Kconfig
index 88a8b5916624..0f345e207675 100644
--- a/drivers/nvme/host/Kconfig
+++ b/drivers/nvme/host/Kconfig

@@ -57,3 +57,18 @@ config NVME_FC
 	  from https://github.com/linux-nvme/nvme-cli.
 
 	  If unsure, say N.
+
+config NVME_TCP
+	tristate "NVM Express over Fabrics TCP host driver"
+	depends on INET
+	depends on BLK_DEV_NVME
+	select NVME_FABRICS
+	help
+	  This provides support for the NVMe over Fabrics protocol using
+	  the TCP transport.  This allows you to use remote block devices
+	  exported using the NVMe protocol set.
+
+	  To configure a NVMe over Fabrics controller use the nvme-cli tool
+	  from https://github.com/linux-nvme/nvme-cli.
+
+	  If unsure, say N.

diff --git a/drivers/nvme/host/Makefile b/drivers/nvme/host/Makefile
index aea459c65ae1..8a4b671c5f0c 100644
--- a/drivers/nvme/host/Makefile
+++ b/drivers/nvme/host/Makefile

@@ -7,6 +7,7 @@ obj-$(CONFIG_BLK_DEV_NVME)		+= nvme.o
 obj-$(CONFIG_NVME_FABRICS)		+= nvme-fabrics.o
 obj-$(CONFIG_NVME_RDMA)			+= nvme-rdma.o
 obj-$(CONFIG_NVME_FC)			+= nvme-fc.o
+obj-$(CONFIG_NVME_TCP)			+= nvme-tcp.o
 
 nvme-core-y				:= core.o
 nvme-core-$(CONFIG_TRACING)		+= trace.o

@@ -21,3 +22,5 @@ nvme-fabrics-y				+= fabrics.o
 nvme-rdma-y				+= rdma.o
 
 nvme-fc-y				+= fc.o
+
+nvme-tcp-y				+= tcp.o

diff --git a/drivers/nvme/host/tcp.c b/drivers/nvme/host/tcp.c
new file mode 100644
index 000000000000..4c583859f0ad
--- /dev/null
+++ b/drivers/nvme/host/tcp.c

@@ -0,0 +1,2306 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * NVMe over Fabrics TCP host.
+ * Copyright (c) 2018 LightBits Labs. All rights reserved.
+ */
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+#include <linux/nvme-tcp.h>
+#include <net/sock.h>
+#include <net/tcp.h>
+#include <linux/blk-mq.h>
+#include <crypto/hash.h>
+
+#include "nvme.h"
+#include "fabrics.h"
+
+struct nvme_tcp_queue;
+
+enum nvme_tcp_send_state {
+	NVME_TCP_SEND_CMD_PDU = 0,
+	NVME_TCP_SEND_H2C_PDU,
+	NVME_TCP_SEND_DATA,
+	NVME_TCP_SEND_DDGST,
+};
+
+struct nvme_tcp_send_ctx {
+	struct bio		*curr_bio;
+	struct iov_iter		iter;
+	size_t			offset;
+	size_t			data_sent;
+	enum nvme_tcp_send_state state;
+};
+
+struct nvme_tcp_recv_ctx {
+	struct iov_iter		iter;
+	struct bio		*curr_bio;
+};