+enum nvmet_tcp_send_state {
+	NVMET_TCP_SEND_DATA_PDU = 0,
+	NVMET_TCP_SEND_DATA,
+	NVMET_TCP_SEND_R2T,
+	NVMET_TCP_SEND_DDGST,
+	NVMET_TCP_SEND_RESPONSE
+};
+
+enum nvmet_tcp_recv_state {
+	NVMET_TCP_RECV_PDU,
+	NVMET_TCP_RECV_DATA,
+	NVMET_TCP_RECV_DDGST,
+	NVMET_TCP_RECV_ERR,
+};

I think you can drop the explicit initialization for
NVMET_TCP_SEND_DATA_PDU.

+struct nvmet_tcp_recv_ctx {
+};

There are no users of this empty struct, so it can probably be
dropped..

+	void (*dr)(struct sock *);
+	void (*sc)(struct sock *);
+	void (*ws)(struct sock *);

These looks very cryptic.  Can you please at least spell out the
full names as used in the networking code (data_ready, etc).

+struct nvmet_tcp_port {
+	struct socket		*sock;
+	struct work_struct	accept_work;
+	struct nvmet_port	*nport;
+	struct sockaddr_storage addr;
+	int			last_cpu;
+	void (*dr)(struct sock *);
+};

Same here.

+	pdu->hdr.plen =
+		cpu_to_le32(pdu->hdr.hlen + hdgst + cmd->req.transfer_len + ddgst);

Overly long line.

+static struct nvmet_tcp_cmd *nvmet_tcp_reverse_list(struct nvmet_tcp_queue *queue, struct llist_node *node)

Way too long line.

Also this function does not reverse a list, it removes from a llist,
adds to a regular list in reverse order and increments a counter.  Maybe
there is a better name?  It would also seem more readable if the
llist_del_all from the caller moved in here.

+{
+	struct nvmet_tcp_cmd *cmd;
+
+	while (node) {
+		struct nvmet_tcp_cmd *cmd = container_of(node, struct nvmet_tcp_cmd, lentry);
+

Also shouldn't this use llist_entry instead of container_of to document
the intent?

+		list_add(&cmd->entry, &queue->resp_send_list);
+		node = node->next;
+		queue->send_list_len++;
+	}
+
+	cmd = list_first_entry(&queue->resp_send_list, struct nvmet_tcp_cmd, entry);
+	return cmd;

Besides the way too long line this can be a direct return.  Then
again moving the assignment of this in would probably make sense
as well.

+}
+
+static struct nvmet_tcp_cmd *nvmet_tcp_fetch_send_command(struct nvmet_tcp_queue *queue)

Another way too long line.  Please just fix this up everwhere.

+	if (!cmd || queue->state == NVMET_TCP_Q_DISCONNECTING) {
+		cmd = nvmet_tcp_fetch_send_command(queue);
+		if (unlikely(!cmd))
+			return 0;
+	}
+
+	if (cmd->state == NVMET_TCP_SEND_DATA_PDU) {
+		ret = nvmet_try_send_data_pdu(cmd);
+		if (ret <= 0)
+			goto done_send;
+	}
+
+	if (cmd->state == NVMET_TCP_SEND_DATA) {
+		ret = nvmet_try_send_data(cmd);
+		if (ret <= 0)
+			goto done_send;
+	}
+
+	if (cmd->state == NVMET_TCP_SEND_DDGST) {
+		ret = nvmet_try_send_ddgst(cmd);
+		if (ret <= 0)
+			goto done_send;
+	}
+
+	if (cmd->state == NVMET_TCP_SEND_R2T) {
+		ret = nvmet_try_send_r2t(cmd, last_in_batch);
+		if (ret <= 0)
+			goto done_send;
+	}
+
+	if (cmd->state == NVMET_TCP_SEND_RESPONSE)
+		ret = nvmet_try_send_response(cmd, last_in_batch);

Use a switch statement?

+	if (queue->left) {
+		return -EAGAIN;
+	} else if (queue->offset == sizeof(struct nvme_tcp_hdr)) {

No need for an else after a return.

+
+	if (unlikely(queue->rcv_state == NVMET_TCP_RECV_ERR))
+		return 0;
+
+	if (queue->rcv_state == NVMET_TCP_RECV_PDU) {
+		result = nvmet_tcp_try_recv_pdu(queue);
+		if (result != 0)
+			goto done_recv;
+	}
+
+	if (queue->rcv_state == NVMET_TCP_RECV_DATA) {
+		result = nvmet_tcp_try_recv_data(queue);
+		if (result != 0)
+			goto done_recv;
+	}
+
+	if (queue->rcv_state == NVMET_TCP_RECV_DDGST) {
+		result = nvmet_tcp_try_recv_ddgst(queue);
+		if (result != 0)
+			goto done_recv;
+	}

switch statement?

+	spin_lock(&queue->state_lock);
+	if (queue->state == NVMET_TCP_Q_DISCONNECTING)
+		goto out;
+
+	queue->state = NVMET_TCP_Q_DISCONNECTING;
+	schedule_work(&queue->release_work);
+out:
+	spin_unlock(&queue->state_lock);

No real need for the goto here.

+static void nvmet_tcp_data_ready(struct sock *sk)
+{
+	struct nvmet_tcp_queue *queue;
+
+	read_lock_bh(&sk->sk_callback_lock);
+	queue = sk->sk_user_data;
+	if (!queue)
+		goto out;
+
+	queue_work_on(queue->cpu, nvmet_tcp_wq, &queue->io_work);
+out:
+	read_unlock_bh(&sk->sk_callback_lock);
+}

This should only need rcu_read_proctection, right?

Also no need for the goto.