Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1893 insertions, 0 deletions

diff --git a/drivers/nvme/target/tcp.c b/drivers/nvme/target/tcp.c
new file mode 100644
index 000000000..ce42afe8f
--- /dev/null
+++ b/drivers/nvme/target/tcp.c
@@ -0,0 +1,1893 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * NVMe over Fabrics TCP target.
+ * 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/inet.h>
+#include <linux/llist.h>
+#include <crypto/hash.h>
+
+#include "nvmet.h"
+
+#define NVMET_TCP_DEF_INLINE_DATA_SIZE	(4 * PAGE_SIZE)
+#define NVMET_TCP_MAXH2CDATA		0x400000 /* 16M arbitrary limit */
+
+/* Define the socket priority to use for connections were it is desirable
+ * that the NIC consider performing optimized packet processing or filtering.
+ * A non-zero value being sufficient to indicate general consideration of any
+ * possible optimization.  Making it a module param allows for alternative
+ * values that may be unique for some NIC implementations.
+ */
+static int so_priority;
+module_param(so_priority, int, 0644);
+MODULE_PARM_DESC(so_priority, "nvmet tcp socket optimize priority");
+
+/* Define a time period (in usecs) that io_work() shall sample an activated
+ * queue before determining it to be idle.  This optional module behavior
+ * can enable NIC solutions that support socket optimized packet processing
+ * using advanced interrupt moderation techniques.
+ */
+static int idle_poll_period_usecs;
+module_param(idle_poll_period_usecs, int, 0644);
+MODULE_PARM_DESC(idle_poll_period_usecs,
+		"nvmet tcp io_work poll till idle time period in usecs");
+
+#define NVMET_TCP_RECV_BUDGET		8
+#define NVMET_TCP_SEND_BUDGET		8
+#define NVMET_TCP_IO_WORK_BUDGET	64
+
+enum nvmet_tcp_send_state {
+	NVMET_TCP_SEND_DATA_PDU,
+	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,
+};
+
+enum {
+	NVMET_TCP_F_INIT_FAILED = (1 << 0),
+};
+
+struct nvmet_tcp_cmd {
+	struct nvmet_tcp_queue		*queue;
+	struct nvmet_req		req;
+
+	struct nvme_tcp_cmd_pdu		*cmd_pdu;
+	struct nvme_tcp_rsp_pdu		*rsp_pdu;
+	struct nvme_tcp_data_pdu	*data_pdu;
+	struct nvme_tcp_r2t_pdu		*r2t_pdu;
+
+	u32				rbytes_done;
+	u32				wbytes_done;
+
+	u32				pdu_len;
+	u32				pdu_recv;
+	int				sg_idx;
+	struct msghdr			recv_msg;
+	struct bio_vec			*iov;
+	u32				flags;
+
+	struct list_head		entry;
+	struct llist_node		lentry;
+
+	/* send state */
+	u32				offset;
+	struct scatterlist		*cur_sg;
+	enum nvmet_tcp_send_state	state;
+
+	__le32				exp_ddgst;
+	__le32				recv_ddgst;
+};
+
+enum nvmet_tcp_queue_state {
+	NVMET_TCP_Q_CONNECTING,
+	NVMET_TCP_Q_LIVE,
+	NVMET_TCP_Q_DISCONNECTING,
+};
+
+struct nvmet_tcp_queue {
+	struct socket		*sock;
+	struct nvmet_tcp_port	*port;
+	struct work_struct	io_work;
+	struct nvmet_cq		nvme_cq;
+	struct nvmet_sq		nvme_sq;
+
+	/* send state */
+	struct nvmet_tcp_cmd	*cmds;
+	unsigned int		nr_cmds;
+	struct list_head	free_list;
+	struct llist_head	resp_list;
+	struct list_head	resp_send_list;
+	int			send_list_len;
+	struct nvmet_tcp_cmd	*snd_cmd;
+
+	/* recv state */
+	int			offset;
+	int			left;
+	enum nvmet_tcp_recv_state rcv_state;
+	struct nvmet_tcp_cmd	*cmd;
+	union nvme_tcp_pdu	pdu;
+
+	/* digest state */
+	bool			hdr_digest;
+	bool			data_digest;
+	struct ahash_request	*snd_hash;
+	struct ahash_request	*rcv_hash;
+
+	unsigned long           poll_end;
+
+	spinlock_t		state_lock;
+	enum nvmet_tcp_queue_state state;
+
+	struct sockaddr_storage	sockaddr;
+	struct sockaddr_storage	sockaddr_peer;
+	struct work_struct	release_work;
+
+	int			idx;
+	struct list_head	queue_list;
+
+	struct nvmet_tcp_cmd	connect;
+
+	struct page_frag_cache	pf_cache;
+
+	void (*data_ready)(struct sock *);
+	void (*state_change)(struct sock *);
+	void (*write_space)(struct sock *);
+};
+
+struct nvmet_tcp_port {
+	struct socket		*sock;
+	struct work_struct	accept_work;
+	struct nvmet_port	*nport;
+	struct sockaddr_storage addr;
+	void (*data_ready)(struct sock *);
+};
+
+static DEFINE_IDA(nvmet_tcp_queue_ida);
+static LIST_HEAD(nvmet_tcp_queue_list);
+static DEFINE_MUTEX(nvmet_tcp_queue_mutex);
+
+static struct workqueue_struct *nvmet_tcp_wq;
+static const struct nvmet_fabrics_ops nvmet_tcp_ops;
+static void nvmet_tcp_free_cmd(struct nvmet_tcp_cmd *c);
+static void nvmet_tcp_free_cmd_buffers(struct nvmet_tcp_cmd *cmd);
+
+static inline u16 nvmet_tcp_cmd_tag(struct nvmet_tcp_queue *queue,
+		struct nvmet_tcp_cmd *cmd)
+{
+	if (unlikely(!queue->nr_cmds)) {
+		/* We didn't allocate cmds yet, send 0xffff */
+		return USHRT_MAX;
+	}
+
+	return cmd - queue->cmds;
+}
+
+static inline bool nvmet_tcp_has_data_in(struct nvmet_tcp_cmd *cmd)
+{
+	return nvme_is_write(cmd->req.cmd) &&
+		cmd->rbytes_done < cmd->req.transfer_len;
+}
+
+static inline bool nvmet_tcp_need_data_in(struct nvmet_tcp_cmd *cmd)
+{
+	return nvmet_tcp_has_data_in(cmd) && !cmd->req.cqe->status;
+}
+
+static inline bool nvmet_tcp_need_data_out(struct nvmet_tcp_cmd *cmd)
+{
+	return !nvme_is_write(cmd->req.cmd) &&
+		cmd->req.transfer_len > 0 &&
+		!cmd->req.cqe->status;
+}
+
+static inline bool nvmet_tcp_has_inline_data(struct nvmet_tcp_cmd *cmd)
+{
+	return nvme_is_write(cmd->req.cmd) && cmd->pdu_len &&
+		!cmd->rbytes_done;
+}
+
+static inline struct nvmet_tcp_cmd *
+nvmet_tcp_get_cmd(struct nvmet_tcp_queue *queue)
+{
+	struct nvmet_tcp_cmd *cmd;
+
+	cmd = list_first_entry_or_null(&queue->free_list,
+				struct nvmet_tcp_cmd, entry);
+	if (!cmd)
+		return NULL;
+	list_del_init(&cmd->entry);
+
+	cmd->rbytes_done = cmd->wbytes_done = 0;
+	cmd->pdu_len = 0;
+	cmd->pdu_recv = 0;
+	cmd->iov = NULL;
+	cmd->flags = 0;
+	return cmd;
+}
+
+static inline void nvmet_tcp_put_cmd(struct nvmet_tcp_cmd *cmd)
+{
+	if (unlikely(cmd == &cmd->queue->connect))
+		return;
+
+	list_add_tail(&cmd->entry, &cmd->queue->free_list);
+}
+
+static inline int queue_cpu(struct nvmet_tcp_queue *queue)
+{
+	return queue->sock->sk->sk_incoming_cpu;
+}
+
+static inline u8 nvmet_tcp_hdgst_len(struct nvmet_tcp_queue *queue)
+{
+	return queue->hdr_digest ? NVME_TCP_DIGEST_LENGTH : 0;
+}
+
+static inline u8 nvmet_tcp_ddgst_len(struct nvmet_tcp_queue *queue)
+{
+	return queue->data_digest ? NVME_TCP_DIGEST_LENGTH : 0;
+}
+
+static inline void nvmet_tcp_hdgst(struct ahash_request *hash,
+		void *pdu, size_t len)
+{
+	struct scatterlist sg;
+
+	sg_init_one(&sg, pdu, len);
+	ahash_request_set_crypt(hash, &sg, pdu + len, len);
+	crypto_ahash_digest(hash);
+}
+
+static int nvmet_tcp_verify_hdgst(struct nvmet_tcp_queue *queue,
+	void *pdu, size_t len)
+{
+	struct nvme_tcp_hdr *hdr = pdu;
+	__le32 recv_digest;
+	__le32 exp_digest;
+
+	if (unlikely(!(hdr->flags & NVME_TCP_F_HDGST))) {
+		pr_err("queue %d: header digest enabled but no header digest\n",
+			queue->idx);
+		return -EPROTO;
+	}
+
+	recv_digest = *(__le32 *)(pdu + hdr->hlen);
+	nvmet_tcp_hdgst(queue->rcv_hash, pdu, len);
+	exp_digest = *(__le32 *)(pdu + hdr->hlen);
+	if (recv_digest != exp_digest) {
+		pr_err("queue %d: header digest error: recv %#x expected %#x\n",
+			queue->idx, le32_to_cpu(recv_digest),
+			le32_to_cpu(exp_digest));
+		return -EPROTO;
+	}
+
+	return 0;
+}
+
+static int nvmet_tcp_check_ddgst(struct nvmet_tcp_queue *queue, void *pdu)
+{
+	struct nvme_tcp_hdr *hdr = pdu;
+	u8 digest_len = nvmet_tcp_hdgst_len(queue);
+	u32 len;
+
+	len = le32_to_cpu(hdr->plen) - hdr->hlen -
+		(hdr->flags & NVME_TCP_F_HDGST ? digest_len : 0);
+
+	if (unlikely(len && !(hdr->flags & NVME_TCP_F_DDGST))) {
+		pr_err("queue %d: data digest flag is cleared\n", queue->idx);
+		return -EPROTO;
+	}
+
+	return 0;
+}
+
+static void nvmet_tcp_free_cmd_buffers(struct nvmet_tcp_cmd *cmd)
+{
+	kfree(cmd->iov);
+	sgl_free(cmd->req.sg);
+	cmd->iov = NULL;
+	cmd->req.sg = NULL;
+}
+
+static void nvmet_tcp_build_pdu_iovec(struct nvmet_tcp_cmd *cmd)
+{
+	struct bio_vec *iov = cmd->iov;
+	struct scatterlist *sg;
+	u32 length, offset, sg_offset;
+	int nr_pages;
+
+	length = cmd->pdu_len;
+	nr_pages = DIV_ROUND_UP(length, PAGE_SIZE);
+	offset = cmd->rbytes_done;
+	cmd->sg_idx = offset / PAGE_SIZE;
+	sg_offset = offset % PAGE_SIZE;
+	sg = &cmd->req.sg[cmd->sg_idx];
+
+	while (length) {
+		u32 iov_len = min_t(u32, length, sg->length - sg_offset);
+
+		bvec_set_page(iov, sg_page(sg), iov_len,
+				sg->offset + sg_offset);
+
+		length -= iov_len;
+		sg = sg_next(sg);
+		iov++;
+		sg_offset = 0;
+	}
+
+	iov_iter_bvec(&cmd->recv_msg.msg_iter, ITER_DEST, cmd->iov,
+		      nr_pages, cmd->pdu_len);
+}
+
+static void nvmet_tcp_fatal_error(struct nvmet_tcp_queue *queue)
+{
+	queue->rcv_state = NVMET_TCP_RECV_ERR;
+	if (queue->nvme_sq.ctrl)
+		nvmet_ctrl_fatal_error(queue->nvme_sq.ctrl);
+	else
+		kernel_sock_shutdown(queue->sock, SHUT_RDWR);
+}
+
+static void nvmet_tcp_socket_error(struct nvmet_tcp_queue *queue, int status)
+{
+	queue->rcv_state = NVMET_TCP_RECV_ERR;
+	if (status == -EPIPE || status == -ECONNRESET)
+		kernel_sock_shutdown(queue->sock, SHUT_RDWR);
+	else
+		nvmet_tcp_fatal_error(queue);
+}
+
+static int nvmet_tcp_map_data(struct nvmet_tcp_cmd *cmd)
+{
+	struct nvme_sgl_desc *sgl = &cmd->req.cmd->common.dptr.sgl;
+	u32 len = le32_to_cpu(sgl->length);
+
+	if (!len)
+		return 0;
+
+	if (sgl->type == ((NVME_SGL_FMT_DATA_DESC << 4) |
+			  NVME_SGL_FMT_OFFSET)) {
+		if (!nvme_is_write(cmd->req.cmd))
+			return NVME_SC_INVALID_FIELD | NVME_SC_DNR;
+
+		if (len > cmd->req.port->inline_data_size)
+			return NVME_SC_SGL_INVALID_OFFSET | NVME_SC_DNR;
+		cmd->pdu_len = len;
+	}
+	cmd->req.transfer_len += len;
+
+	cmd->req.sg = sgl_alloc(len, GFP_KERNEL, &cmd->req.sg_cnt);
+	if (!cmd->req.sg)
+		return NVME_SC_INTERNAL;
+	cmd->cur_sg = cmd->req.sg;
+
+	if (nvmet_tcp_has_data_in(cmd)) {
+		cmd->iov = kmalloc_array(cmd->req.sg_cnt,
+				sizeof(*cmd->iov), GFP_KERNEL);
+		if (!cmd->iov)
+			goto err;
+	}
+
+	return 0;
+err:
+	nvmet_tcp_free_cmd_buffers(cmd);
+	return NVME_SC_INTERNAL;
+}
+
+static void nvmet_tcp_calc_ddgst(struct ahash_request *hash,
+		struct nvmet_tcp_cmd *cmd)
+{
+	ahash_request_set_crypt(hash, cmd->req.sg,
+		(void *)&cmd->exp_ddgst, cmd->req.transfer_len);
+	crypto_ahash_digest(hash);
+}
+
+static void nvmet_setup_c2h_data_pdu(struct nvmet_tcp_cmd *cmd)
+{
+	struct nvme_tcp_data_pdu *pdu = cmd->data_pdu;
+	struct nvmet_tcp_queue *queue = cmd->queue;
+	u8 hdgst = nvmet_tcp_hdgst_len(cmd->queue);
+	u8 ddgst = nvmet_tcp_ddgst_len(cmd->queue);
+
+	cmd->offset = 0;
+	cmd->state = NVMET_TCP_SEND_DATA_PDU;
+
+	pdu->hdr.type = nvme_tcp_c2h_data;
+	pdu->hdr.flags = NVME_TCP_F_DATA_LAST | (queue->nvme_sq.sqhd_disabled ?
+						NVME_TCP_F_DATA_SUCCESS : 0);
+	pdu->hdr.hlen = sizeof(*pdu);
+	pdu->hdr.pdo = pdu->hdr.hlen + hdgst;
+	pdu->hdr.plen =
+		cpu_to_le32(pdu->hdr.hlen + hdgst +
+				cmd->req.transfer_len + ddgst);
+	pdu->command_id = cmd->req.cqe->command_id;
+	pdu->data_length = cpu_to_le32(cmd->req.transfer_len);
+	pdu->data_offset = cpu_to_le32(cmd->wbytes_done);
+
+	if (queue->data_digest) {
+		pdu->hdr.flags |= NVME_TCP_F_DDGST;
+		nvmet_tcp_calc_ddgst(queue->snd_hash, cmd);
+	}
+
+	if (cmd->queue->hdr_digest) {
+		pdu->hdr.flags |= NVME_TCP_F_HDGST;
+		nvmet_tcp_hdgst(queue->snd_hash, pdu, sizeof(*pdu));
+	}
+}
+
+static void nvmet_setup_r2t_pdu(struct nvmet_tcp_cmd *cmd)
+{
+	struct nvme_tcp_r2t_pdu *pdu = cmd->r2t_pdu;
+	struct nvmet_tcp_queue *queue = cmd->queue;
+	u8 hdgst = nvmet_tcp_hdgst_len(cmd->queue);
+
+	cmd->offset = 0;
+	cmd->state = NVMET_TCP_SEND_R2T;
+
+	pdu->hdr.type = nvme_tcp_r2t;
+	pdu->hdr.flags = 0;
+	pdu->hdr.hlen = sizeof(*pdu);
+	pdu->hdr.pdo = 0;
+	pdu->hdr.plen = cpu_to_le32(pdu->hdr.hlen + hdgst);
+
+	pdu->command_id = cmd->req.cmd->common.command_id;
+	pdu->ttag = nvmet_tcp_cmd_tag(cmd->queue, cmd);
+	pdu->r2t_length = cpu_to_le32(cmd->req.transfer_len - cmd->rbytes_done);
+	pdu->r2t_offset = cpu_to_le32(cmd->rbytes_done);
+	if (cmd->queue->hdr_digest) {
+		pdu->hdr.flags |= NVME_TCP_F_HDGST;
+		nvmet_tcp_hdgst(queue->snd_hash, pdu, sizeof(*pdu));
+	}
+}
+
+static void nvmet_setup_response_pdu(struct nvmet_tcp_cmd *cmd)
+{
+	struct nvme_tcp_rsp_pdu *pdu = cmd->rsp_pdu;
+	struct nvmet_tcp_queue *queue = cmd->queue;
+	u8 hdgst = nvmet_tcp_hdgst_len(cmd->queue);
+
+	cmd->offset = 0;
+	cmd->state = NVMET_TCP_SEND_RESPONSE;
+
+	pdu->hdr.type = nvme_tcp_rsp;
+	pdu->hdr.flags = 0;
+	pdu->hdr.hlen = sizeof(*pdu);
+	pdu->hdr.pdo = 0;
+	pdu->hdr.plen = cpu_to_le32(pdu->hdr.hlen + hdgst);
+	if (cmd->queue->hdr_digest) {
+		pdu->hdr.flags |= NVME_TCP_F_HDGST;
+		nvmet_tcp_hdgst(queue->snd_hash, pdu, sizeof(*pdu));
+	}
+}
+
+static void nvmet_tcp_process_resp_list(struct nvmet_tcp_queue *queue)
+{
+	struct llist_node *node;
+	struct nvmet_tcp_cmd *cmd;
+
+	for (node = llist_del_all(&queue->resp_list); node; node = node->next) {
+		cmd = llist_entry(node, struct nvmet_tcp_cmd, lentry);
+		list_add(&cmd->entry, &queue->resp_send_list);
+		queue->send_list_len++;
+	}
+}
+
+static struct nvmet_tcp_cmd *nvmet_tcp_fetch_cmd(struct nvmet_tcp_queue *queue)
+{
+	queue->snd_cmd = list_first_entry_or_null(&queue->resp_send_list,
+				struct nvmet_tcp_cmd, entry);
+	if (!queue->snd_cmd) {
+		nvmet_tcp_process_resp_list(queue);
+		queue->snd_cmd =
+			list_first_entry_or_null(&queue->resp_send_list,
+					struct nvmet_tcp_cmd, entry);
+		if (unlikely(!queue->snd_cmd))
+			return NULL;
+	}
+
+	list_del_init(&queue->snd_cmd->entry);
+	queue->send_list_len--;
+
+	if (nvmet_tcp_need_data_out(queue->snd_cmd))
+		nvmet_setup_c2h_data_pdu(queue->snd_cmd);
+	else if (nvmet_tcp_need_data_in(queue->snd_cmd))
+		nvmet_setup_r2t_pdu(queue->snd_cmd);
+	else
+		nvmet_setup_response_pdu(queue->snd_cmd);
+
+	return queue->snd_cmd;
+}
+
+static void nvmet_tcp_queue_response(struct nvmet_req *req)
+{
+	struct nvmet_tcp_cmd *cmd =
+		container_of(req, struct nvmet_tcp_cmd, req);
+	struct nvmet_tcp_queue	*queue = cmd->queue;
+	struct nvme_sgl_desc *sgl;
+	u32 len;
+
+	if (unlikely(cmd == queue->cmd)) {
+		sgl = &cmd->req.cmd->common.dptr.sgl;
+		len = le32_to_cpu(sgl->length);
+
+		/*
+		 * Wait for inline data before processing the response.
+		 * Avoid using helpers, this might happen before
+		 * nvmet_req_init is completed.
+		 */
+		if (queue->rcv_state == NVMET_TCP_RECV_PDU &&
+		    len && len <= cmd->req.port->inline_data_size &&
+		    nvme_is_write(cmd->req.cmd))
+			return;
+	}
+
+	llist_add(&cmd->lentry, &queue->resp_list);
+	queue_work_on(queue_cpu(queue), nvmet_tcp_wq, &cmd->queue->io_work);
+}
+
+static void nvmet_tcp_execute_request(struct nvmet_tcp_cmd *cmd)
+{
+	if (unlikely(cmd->flags & NVMET_TCP_F_INIT_FAILED))
+		nvmet_tcp_queue_response(&cmd->req);
+	else
+		cmd->req.execute(&cmd->req);
+}
+
+static int nvmet_try_send_data_pdu(struct nvmet_tcp_cmd *cmd)
+{
+	u8 hdgst = nvmet_tcp_hdgst_len(cmd->queue);
+	int left = sizeof(*cmd->data_pdu) - cmd->offset + hdgst;
+	int ret;
+
+	ret = kernel_sendpage(cmd->queue->sock, virt_to_page(cmd->data_pdu),
+			offset_in_page(cmd->data_pdu) + cmd->offset,
+			left, MSG_DONTWAIT | MSG_MORE | MSG_SENDPAGE_NOTLAST);
+	if (ret <= 0)
+		return ret;
+
+	cmd->offset += ret;
+	left -= ret;
+
+	if (left)
+		return -EAGAIN;
+
+	cmd->state = NVMET_TCP_SEND_DATA;
+	cmd->offset  = 0;
+	return 1;
+}
+
+static int nvmet_try_send_data(struct nvmet_tcp_cmd *cmd, bool last_in_batch)
+{
+	struct nvmet_tcp_queue *queue = cmd->queue;
+	int ret;
+
+	while (cmd->cur_sg) {
+		struct page *page = sg_page(cmd->cur_sg);
+		u32 left = cmd->cur_sg->length - cmd->offset;
+		int flags = MSG_DONTWAIT;
+
+		if ((!last_in_batch && cmd->queue->send_list_len) ||
+		    cmd->wbytes_done + left < cmd->req.transfer_len ||
+		    queue->data_digest || !queue->nvme_sq.sqhd_disabled)
+			flags |= MSG_MORE | MSG_SENDPAGE_NOTLAST;
+
+		ret = kernel_sendpage(cmd->queue->sock, page, cmd->offset,
+					left, flags);
+		if (ret <= 0)
+			return ret;
+
+		cmd->offset += ret;
+		cmd->wbytes_done += ret;
+
+		/* Done with sg?*/
+		if (cmd->offset == cmd->cur_sg->length) {
+			cmd->cur_sg = sg_next(cmd->cur_sg);
+			cmd->offset = 0;
+		}
+	}
+
+	if (queue->data_digest) {
+		cmd->state = NVMET_TCP_SEND_DDGST;
+		cmd->offset = 0;
+	} else {
+		if (queue->nvme_sq.sqhd_disabled) {
+			cmd->queue->snd_cmd = NULL;
+			nvmet_tcp_put_cmd(cmd);
+		} else {
+			nvmet_setup_response_pdu(cmd);
+		}
+	}
+
+	if (queue->nvme_sq.sqhd_disabled)
+		nvmet_tcp_free_cmd_buffers(cmd);
+
+	return 1;
+
+}
+
+static int nvmet_try_send_response(struct nvmet_tcp_cmd *cmd,
+		bool last_in_batch)
+{
+	u8 hdgst = nvmet_tcp_hdgst_len(cmd->queue);
+	int left = sizeof(*cmd->rsp_pdu) - cmd->offset + hdgst;
+	int flags = MSG_DONTWAIT;
+	int ret;
+
+	if (!last_in_batch && cmd->queue->send_list_len)
+		flags |= MSG_MORE | MSG_SENDPAGE_NOTLAST;
+	else
+		flags |= MSG_EOR;
+
+	ret = kernel_sendpage(cmd->queue->sock, virt_to_page(cmd->rsp_pdu),
+		offset_in_page(cmd->rsp_pdu) + cmd->offset, left, flags);
+	if (ret <= 0)
+		return ret;
+	cmd->offset += ret;
+	left -= ret;
+
+	if (left)
+		return -EAGAIN;
+
+	nvmet_tcp_free_cmd_buffers(cmd);
+	cmd->queue->snd_cmd = NULL;
+	nvmet_tcp_put_cmd(cmd);
+	return 1;
+}
+
+static int nvmet_try_send_r2t(struct nvmet_tcp_cmd *cmd, bool last_in_batch)
+{
+	u8 hdgst = nvmet_tcp_hdgst_len(cmd->queue);
+	int left = sizeof(*cmd->r2t_pdu) - cmd->offset + hdgst;
+	int flags = MSG_DONTWAIT;
+	int ret;
+
+	if (!last_in_batch && cmd->queue->send_list_len)
+		flags |= MSG_MORE | MSG_SENDPAGE_NOTLAST;
+	else
+		flags |= MSG_EOR;
+
+	ret = kernel_sendpage(cmd->queue->sock, virt_to_page(cmd->r2t_pdu),
+		offset_in_page(cmd->r2t_pdu) + cmd->offset, left, flags);
+	if (ret <= 0)
+		return ret;
+	cmd->offset += ret;
+	left -= ret;
+
+	if (left)
+		return -EAGAIN;
+
+	cmd->queue->snd_cmd = NULL;
+	return 1;
+}
+
+static int nvmet_try_send_ddgst(struct nvmet_tcp_cmd *cmd, bool last_in_batch)
+{
+	struct nvmet_tcp_queue *queue = cmd->queue;
+	int left = NVME_TCP_DIGEST_LENGTH - cmd->offset;
+	struct msghdr msg = { .msg_flags = MSG_DONTWAIT };
+	struct kvec iov = {
+		.iov_base = (u8 *)&cmd->exp_ddgst + cmd->offset,
+		.iov_len = left
+	};
+	int ret;
+
+	if (!last_in_batch && cmd->queue->send_list_len)
+		msg.msg_flags |= MSG_MORE;
+	else
+		msg.msg_flags |= MSG_EOR;
+
+	ret = kernel_sendmsg(queue->sock, &msg, &iov, 1, iov.iov_len);
+	if (unlikely(ret <= 0))
+		return ret;
+
+	cmd->offset += ret;
+	left -= ret;
+
+	if (left)
+		return -EAGAIN;
+
+	if (queue->nvme_sq.sqhd_disabled) {
+		cmd->queue->snd_cmd = NULL;
+		nvmet_tcp_put_cmd(cmd);
+	} else {
+		nvmet_setup_response_pdu(cmd);
+	}
+	return 1;
+}
+
+static int nvmet_tcp_try_send_one(struct nvmet_tcp_queue *queue,
+		bool last_in_batch)
+{
+	struct nvmet_tcp_cmd *cmd = queue->snd_cmd;
+	int ret = 0;
+
+	if (!cmd || queue->state == NVMET_TCP_Q_DISCONNECTING) {
+		cmd = nvmet_tcp_fetch_cmd(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, last_in_batch);
+		if (ret <= 0)
+			goto done_send;
+	}
+
+	if (cmd->state == NVMET_TCP_SEND_DDGST) {
+		ret = nvmet_try_send_ddgst(cmd, last_in_batch);
+		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);
+
+done_send:
+	if (ret < 0) {
+		if (ret == -EAGAIN)
+			return 0;
+		return ret;
+	}
+
+	return 1;
+}
+
+static int nvmet_tcp_try_send(struct nvmet_tcp_queue *queue,
+		int budget, int *sends)
+{
+	int i, ret = 0;
+
+	for (i = 0; i < budget; i++) {
+		ret = nvmet_tcp_try_send_one(queue, i == budget - 1);
+		if (unlikely(ret < 0)) {
+			nvmet_tcp_socket_error(queue, ret);
+			goto done;
+		} else if (ret == 0) {
+			break;
+		}
+		(*sends)++;
+	}
+done:
+	return ret;
+}
+
+static void nvmet_prepare_receive_pdu(struct nvmet_tcp_queue *queue)
+{
+	queue->offset = 0;
+	queue->left = sizeof(struct nvme_tcp_hdr);
+	queue->cmd = NULL;
+	queue->rcv_state = NVMET_TCP_RECV_PDU;
+}
+
+static void nvmet_tcp_free_crypto(struct nvmet_tcp_queue *queue)
+{
+	struct crypto_ahash *tfm = crypto_ahash_reqtfm(queue->rcv_hash);
+
+	ahash_request_free(queue->rcv_hash);
+	ahash_request_free(queue->snd_hash);
+	crypto_free_ahash(tfm);
+}
+
+static int nvmet_tcp_alloc_crypto(struct nvmet_tcp_queue *queue)
+{
+	struct crypto_ahash *tfm;
+
+	tfm = crypto_alloc_ahash("crc32c", 0, CRYPTO_ALG_ASYNC);
+	if (IS_ERR(tfm))
+		return PTR_ERR(tfm);
+
+	queue->snd_hash = ahash_request_alloc(tfm, GFP_KERNEL);
+	if (!queue->snd_hash)
+		goto free_tfm;
+	ahash_request_set_callback(queue->snd_hash, 0, NULL, NULL);
+
+	queue->rcv_hash = ahash_request_alloc(tfm, GFP_KERNEL);
+	if (!queue->rcv_hash)
+		goto free_snd_hash;
+	ahash_request_set_callback(queue->rcv_hash, 0, NULL, NULL);
+
+	return 0;
+free_snd_hash:
+	ahash_request_free(queue->snd_hash);
+free_tfm:
+	crypto_free_ahash(tfm);
+	return -ENOMEM;
+}
+
+
+static int nvmet_tcp_handle_icreq(struct nvmet_tcp_queue *queue)
+{
+	struct nvme_tcp_icreq_pdu *icreq = &queue->pdu.icreq;
+	struct nvme_tcp_icresp_pdu *icresp = &queue->pdu.icresp;
+	struct msghdr msg = {};
+	struct kvec iov;
+	int ret;
+
+	if (le32_to_cpu(icreq->hdr.plen) != sizeof(struct nvme_tcp_icreq_pdu)) {
+		pr_err("bad nvme-tcp pdu length (%d)\n",
+			le32_to_cpu(icreq->hdr.plen));
+		nvmet_tcp_fatal_error(queue);
+	}
+
+	if (icreq->pfv != NVME_TCP_PFV_1_0) {
+		pr_err("queue %d: bad pfv %d\n", queue->idx, icreq->pfv);
+		return -EPROTO;
+	}
+
+	if (icreq->hpda != 0) {
+		pr_err("queue %d: unsupported hpda %d\n", queue->idx,
+			icreq->hpda);
+		return -EPROTO;
+	}
+
+	queue->hdr_digest = !!(icreq->digest & NVME_TCP_HDR_DIGEST_ENABLE);
+	queue->data_digest = !!(icreq->digest & NVME_TCP_DATA_DIGEST_ENABLE);
+	if (queue->hdr_digest || queue->data_digest) {
+		ret = nvmet_tcp_alloc_crypto(queue);
+		if (ret)
+			return ret;
+	}
+
+	memset(icresp, 0, sizeof(*icresp));
+	icresp->hdr.type = nvme_tcp_icresp;
+	icresp->hdr.hlen = sizeof(*icresp);
+	icresp->hdr.pdo = 0;
+	icresp->hdr.plen = cpu_to_le32(icresp->hdr.hlen);
+	icresp->pfv = cpu_to_le16(NVME_TCP_PFV_1_0);
+	icresp->maxdata = cpu_to_le32(NVMET_TCP_MAXH2CDATA);
+	icresp->cpda = 0;
+	if (queue->hdr_digest)
+		icresp->digest |= NVME_TCP_HDR_DIGEST_ENABLE;
+	if (queue->data_digest)
+		icresp->digest |= NVME_TCP_DATA_DIGEST_ENABLE;
+
+	iov.iov_base = icresp;
+	iov.iov_len = sizeof(*icresp);
+	ret = kernel_sendmsg(queue->sock, &msg, &iov, 1, iov.iov_len);
+	if (ret < 0)
+		return ret; /* queue removal will cleanup */
+
+	queue->state = NVMET_TCP_Q_LIVE;
+	nvmet_prepare_receive_pdu(queue);
+	return 0;
+}
+
+static void nvmet_tcp_handle_req_failure(struct nvmet_tcp_queue *queue,
+		struct nvmet_tcp_cmd *cmd, struct nvmet_req *req)
+{
+	size_t data_len = le32_to_cpu(req->cmd->common.dptr.sgl.length);
+	int ret;
+
+	/*
+	 * This command has not been processed yet, hence we are trying to
+	 * figure out if there is still pending data left to receive. If
+	 * we don't, we can simply prepare for the next pdu and bail out,
+	 * otherwise we will need to prepare a buffer and receive the
+	 * stale data before continuing forward.
+	 */
+	if (!nvme_is_write(cmd->req.cmd) || !data_len ||
+	    data_len > cmd->req.port->inline_data_size) {
+		nvmet_prepare_receive_pdu(queue);
+		return;
+	}
+
+	ret = nvmet_tcp_map_data(cmd);
+	if (unlikely(ret)) {
+		pr_err("queue %d: failed to map data\n", queue->idx);
+		nvmet_tcp_fatal_error(queue);
+		return;
+	}
+
+	queue->rcv_state = NVMET_TCP_RECV_DATA;
+	nvmet_tcp_build_pdu_iovec(cmd);
+	cmd->flags |= NVMET_TCP_F_INIT_FAILED;
+}
+
+static int nvmet_tcp_handle_h2c_data_pdu(struct nvmet_tcp_queue *queue)
+{
+	struct nvme_tcp_data_pdu *data = &queue->pdu.data;
+	struct nvmet_tcp_cmd *cmd;
+	unsigned int exp_data_len;
+
+	if (likely(queue->nr_cmds)) {
+		if (unlikely(data->ttag >= queue->nr_cmds)) {
+			pr_err("queue %d: received out of bound ttag %u, nr_cmds %u\n",
+				queue->idx, data->ttag, queue->nr_cmds);
+			nvmet_tcp_fatal_error(queue);
+			return -EPROTO;
+		}
+		cmd = &queue->cmds[data->ttag];
+	} else {
+		cmd = &queue->connect;
+	}
+
+	if (le32_to_cpu(data->data_offset) != cmd->rbytes_done) {
+		pr_err("ttag %u unexpected data offset %u (expected %u)\n",
+			data->ttag, le32_to_cpu(data->data_offset),
+			cmd->rbytes_done);
+		/* FIXME: use path and transport errors */
+		nvmet_tcp_fatal_error(queue);
+		return -EPROTO;
+	}
+
+	exp_data_len = le32_to_cpu(data->hdr.plen) -
+			nvmet_tcp_hdgst_len(queue) -
+			nvmet_tcp_ddgst_len(queue) -
+			sizeof(*data);
+
+	cmd->pdu_len = le32_to_cpu(data->data_length);
+	if (unlikely(cmd->pdu_len != exp_data_len ||
+		     cmd->pdu_len == 0 ||
+		     cmd->pdu_len > NVMET_TCP_MAXH2CDATA)) {
+		pr_err("H2CData PDU len %u is invalid\n", cmd->pdu_len);
+		/* FIXME: use proper transport errors */
+		nvmet_tcp_fatal_error(queue);
+		return -EPROTO;
+	}
+	cmd->pdu_recv = 0;
+	nvmet_tcp_build_pdu_iovec(cmd);
+	queue->cmd = cmd;
+	queue->rcv_state = NVMET_TCP_RECV_DATA;
+
+	return 0;
+}
+
+static int nvmet_tcp_done_recv_pdu(struct nvmet_tcp_queue *queue)
+{
+	struct nvme_tcp_hdr *hdr = &queue->pdu.cmd.hdr;
+	struct nvme_command *nvme_cmd = &queue->pdu.cmd.cmd;
+	struct nvmet_req *req;
+	int ret;
+
+	if (unlikely(queue->state == NVMET_TCP_Q_CONNECTING)) {
+		if (hdr->type != nvme_tcp_icreq) {
+			pr_err("unexpected pdu type (%d) before icreq\n",
+				hdr->type);
+			nvmet_tcp_fatal_error(queue);
+			return -EPROTO;
+		}
+		return nvmet_tcp_handle_icreq(queue);
+	}
+
+	if (unlikely(hdr->type == nvme_tcp_icreq)) {
+		pr_err("queue %d: received icreq pdu in state %d\n",
+			queue->idx, queue->state);
+		nvmet_tcp_fatal_error(queue);
+		return -EPROTO;
+	}
+
+	if (hdr->type == nvme_tcp_h2c_data) {
+		ret = nvmet_tcp_handle_h2c_data_pdu(queue);
+		if (unlikely(ret))
+			return ret;
+		return 0;
+	}
+
+	queue->cmd = nvmet_tcp_get_cmd(queue);
+	if (unlikely(!queue->cmd)) {
+		/* This should never happen */
+		pr_err("queue %d: out of commands (%d) send_list_len: %d, opcode: %d",
+			queue->idx, queue->nr_cmds, queue->send_list_len,
+			nvme_cmd->common.opcode);
+		nvmet_tcp_fatal_error(queue);
+		return -ENOMEM;
+	}
+
+	req = &queue->cmd->req;
+	memcpy(req->cmd, nvme_cmd, sizeof(*nvme_cmd));
+
+	if (unlikely(!nvmet_req_init(req, &queue->nvme_cq,
+			&queue->nvme_sq, &nvmet_tcp_ops))) {
+		pr_err("failed cmd %p id %d opcode %d, data_len: %d\n",
+			req->cmd, req->cmd->common.command_id,
+			req->cmd->common.opcode,
+			le32_to_cpu(req->cmd->common.dptr.sgl.length));
+
+		nvmet_tcp_handle_req_failure(queue, queue->cmd, req);
+		return 0;
+	}
+
+	ret = nvmet_tcp_map_data(queue->cmd);
+	if (unlikely(ret)) {
+		pr_err("queue %d: failed to map data\n", queue->idx);
+		if (nvmet_tcp_has_inline_data(queue->cmd))
+			nvmet_tcp_fatal_error(queue);
+		else
+			nvmet_req_complete(req, ret);
+		ret = -EAGAIN;
+		goto out;
+	}
+
+	if (nvmet_tcp_need_data_in(queue->cmd)) {
+		if (nvmet_tcp_has_inline_data(queue->cmd)) {
+			queue->rcv_state = NVMET_TCP_RECV_DATA;
+			nvmet_tcp_build_pdu_iovec(queue->cmd);
+			return 0;
+		}
+		/* send back R2T */
+		nvmet_tcp_queue_response(&queue->cmd->req);
+		goto out;
+	}
+
+	queue->cmd->req.execute(&queue->cmd->req);
+out:
+	nvmet_prepare_receive_pdu(queue);
+	return ret;
+}
+
+static const u8 nvme_tcp_pdu_sizes[] = {
+	[nvme_tcp_icreq]	= sizeof(struct nvme_tcp_icreq_pdu),
+	[nvme_tcp_cmd]		= sizeof(struct nvme_tcp_cmd_pdu),
+	[nvme_tcp_h2c_data]	= sizeof(struct nvme_tcp_data_pdu),
+};
+
+static inline u8 nvmet_tcp_pdu_size(u8 type)
+{
+	size_t idx = type;
+
+	return (idx < ARRAY_SIZE(nvme_tcp_pdu_sizes) &&
+		nvme_tcp_pdu_sizes[idx]) ?
+			nvme_tcp_pdu_sizes[idx] : 0;
+}
+
+static inline bool nvmet_tcp_pdu_valid(u8 type)
+{
+	switch (type) {
+	case nvme_tcp_icreq:
+	case nvme_tcp_cmd:
+	case nvme_tcp_h2c_data:
+		/* fallthru */
+		return true;
+	}
+
+	return false;
+}
+
+static int nvmet_tcp_try_recv_pdu(struct nvmet_tcp_queue *queue)
+{
+	struct nvme_tcp_hdr *hdr = &queue->pdu.cmd.hdr;
+	int len;
+	struct kvec iov;
+	struct msghdr msg = { .msg_flags = MSG_DONTWAIT };
+
+recv:
+	iov.iov_base = (void *)&queue->pdu + queue->offset;
+	iov.iov_len = queue->left;
+	len = kernel_recvmsg(queue->sock, &msg, &iov, 1,
+			iov.iov_len, msg.msg_flags);
+	if (unlikely(len < 0))
+		return len;
+
+	queue->offset += len;
+	queue->left -= len;
+	if (queue->left)
+		return -EAGAIN;
+
+	if (queue->offset == sizeof(struct nvme_tcp_hdr)) {
+		u8 hdgst = nvmet_tcp_hdgst_len(queue);
+
+		if (unlikely(!nvmet_tcp_pdu_valid(hdr->type))) {
+			pr_err("unexpected pdu type %d\n", hdr->type);
+			nvmet_tcp_fatal_error(queue);
+			return -EIO;
+		}
+
+		if (unlikely(hdr->hlen != nvmet_tcp_pdu_size(hdr->type))) {
+			pr_err("pdu %d bad hlen %d\n", hdr->type, hdr->hlen);
+			return -EIO;
+		}
+
+		queue->left = hdr->hlen - queue->offset + hdgst;
+		goto recv;
+	}
+
+	if (queue->hdr_digest &&
+	    nvmet_tcp_verify_hdgst(queue, &queue->pdu, hdr->hlen)) {
+		nvmet_tcp_fatal_error(queue); /* fatal */
+		return -EPROTO;
+	}
+
+	if (queue->data_digest &&
+	    nvmet_tcp_check_ddgst(queue, &queue->pdu)) {
+		nvmet_tcp_fatal_error(queue); /* fatal */
+		return -EPROTO;
+	}
+
+	return nvmet_tcp_done_recv_pdu(queue);
+}
+
+static void nvmet_tcp_prep_recv_ddgst(struct nvmet_tcp_cmd *cmd)
+{
+	struct nvmet_tcp_queue *queue = cmd->queue;
+
+	nvmet_tcp_calc_ddgst(queue->rcv_hash, cmd);
+	queue->offset = 0;
+	queue->left = NVME_TCP_DIGEST_LENGTH;
+	queue->rcv_state = NVMET_TCP_RECV_DDGST;
+}
+
+static int nvmet_tcp_try_recv_data(struct nvmet_tcp_queue *queue)
+{
+	struct nvmet_tcp_cmd  *cmd = queue->cmd;
+	int ret;
+
+	while (msg_data_left(&cmd->recv_msg)) {
+		ret = sock_recvmsg(cmd->queue->sock, &cmd->recv_msg,
+			cmd->recv_msg.msg_flags);
+		if (ret <= 0)
+			return ret;
+
+		cmd->pdu_recv += ret;
+		cmd->rbytes_done += ret;
+	}
+
+	if (queue->data_digest) {
+		nvmet_tcp_prep_recv_ddgst(cmd);
+		return 0;
+	}
+
+	if (cmd->rbytes_done == cmd->req.transfer_len)
+		nvmet_tcp_execute_request(cmd);
+
+	nvmet_prepare_receive_pdu(queue);
+	return 0;
+}
+
+static int nvmet_tcp_try_recv_ddgst(struct nvmet_tcp_queue *queue)
+{
+	struct nvmet_tcp_cmd *cmd = queue->cmd;
+	int ret;
+	struct msghdr msg = { .msg_flags = MSG_DONTWAIT };
+	struct kvec iov = {
+		.iov_base = (void *)&cmd->recv_ddgst + queue->offset,
+		.iov_len = queue->left
+	};
+
+	ret = kernel_recvmsg(queue->sock, &msg, &iov, 1,
+			iov.iov_len, msg.msg_flags);
+	if (unlikely(ret < 0))
+		return ret;
+
+	queue->offset += ret;
+	queue->left -= ret;
+	if (queue->left)
+		return -EAGAIN;
+
+	if (queue->data_digest && cmd->exp_ddgst != cmd->recv_ddgst) {
+		pr_err("queue %d: cmd %d pdu (%d) data digest error: recv %#x expected %#x\n",
+			queue->idx, cmd->req.cmd->common.command_id,
+			queue->pdu.cmd.hdr.type, le32_to_cpu(cmd->recv_ddgst),
+			le32_to_cpu(cmd->exp_ddgst));
+		nvmet_req_uninit(&cmd->req);
+		nvmet_tcp_free_cmd_buffers(cmd);
+		nvmet_tcp_fatal_error(queue);
+		ret = -EPROTO;
+		goto out;
+	}
+
+	if (cmd->rbytes_done == cmd->req.transfer_len)
+		nvmet_tcp_execute_request(cmd);
+
+	ret = 0;
+out:
+	nvmet_prepare_receive_pdu(queue);
+	return ret;
+}
+
+static int nvmet_tcp_try_recv_one(struct nvmet_tcp_queue *queue)
+{
+	int result = 0;
+
+	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;
+	}
+
+done_recv:
+	if (result < 0) {
+		if (result == -EAGAIN)
+			return 0;
+		return result;
+	}
+	return 1;
+}
+
+static int nvmet_tcp_try_recv(struct nvmet_tcp_queue *queue,
+		int budget, int *recvs)
+{
+	int i, ret = 0;
+
+	for (i = 0; i < budget; i++) {
+		ret = nvmet_tcp_try_recv_one(queue);
+		if (unlikely(ret < 0)) {
+			nvmet_tcp_socket_error(queue, ret);
+			goto done;
+		} else if (ret == 0) {
+			break;
+		}
+		(*recvs)++;
+	}
+done:
+	return ret;
+}
+
+static void nvmet_tcp_schedule_release_queue(struct nvmet_tcp_queue *queue)
+{
+	spin_lock(&queue->state_lock);
+	if (queue->state != NVMET_TCP_Q_DISCONNECTING) {
+		queue->state = NVMET_TCP_Q_DISCONNECTING;
+		queue_work(nvmet_wq, &queue->release_work);
+	}
+	spin_unlock(&queue->state_lock);
+}
+
+static inline void nvmet_tcp_arm_queue_deadline(struct nvmet_tcp_queue *queue)
+{
+	queue->poll_end = jiffies + usecs_to_jiffies(idle_poll_period_usecs);
+}
+
+static bool nvmet_tcp_check_queue_deadline(struct nvmet_tcp_queue *queue,
+		int ops)
+{
+	if (!idle_poll_period_usecs)
+		return false;
+
+	if (ops)
+		nvmet_tcp_arm_queue_deadline(queue);
+
+	return !time_after(jiffies, queue->poll_end);
+}
+
+static void nvmet_tcp_io_work(struct work_struct *w)
+{
+	struct nvmet_tcp_queue *queue =
+		container_of(w, struct nvmet_tcp_queue, io_work);
+	bool pending;
+	int ret, ops = 0;
+
+	do {
+		pending = false;
+
+		ret = nvmet_tcp_try_recv(queue, NVMET_TCP_RECV_BUDGET, &ops);
+		if (ret > 0)
+			pending = true;
+		else if (ret < 0)
+			return;
+
+		ret = nvmet_tcp_try_send(queue, NVMET_TCP_SEND_BUDGET, &ops);
+		if (ret > 0)
+			pending = true;
+		else if (ret < 0)
+			return;
+
+	} while (pending && ops < NVMET_TCP_IO_WORK_BUDGET);
+
+	/*
+	 * Requeue the worker if idle deadline period is in progress or any
+	 * ops activity was recorded during the do-while loop above.
+	 */
+	if (nvmet_tcp_check_queue_deadline(queue, ops) || pending)
+		queue_work_on(queue_cpu(queue), nvmet_tcp_wq, &queue->io_work);
+}
+
+static int nvmet_tcp_alloc_cmd(struct nvmet_tcp_queue *queue,
+		struct nvmet_tcp_cmd *c)
+{
+	u8 hdgst = nvmet_tcp_hdgst_len(queue);
+
+	c->queue = queue;
+	c->req.port = queue->port->nport;
+
+	c->cmd_pdu = page_frag_alloc(&queue->pf_cache,
+			sizeof(*c->cmd_pdu) + hdgst, GFP_KERNEL | __GFP_ZERO);
+	if (!c->cmd_pdu)
+		return -ENOMEM;
+	c->req.cmd = &c->cmd_pdu->cmd;
+
+	c->rsp_pdu = page_frag_alloc(&queue->pf_cache,
+			sizeof(*c->rsp_pdu) + hdgst, GFP_KERNEL | __GFP_ZERO);
+	if (!c->rsp_pdu)
+		goto out_free_cmd;
+	c->req.cqe = &c->rsp_pdu->cqe;
+
+	c->data_pdu = page_frag_alloc(&queue->pf_cache,
+			sizeof(*c->data_pdu) + hdgst, GFP_KERNEL | __GFP_ZERO);
+	if (!c->data_pdu)
+		goto out_free_rsp;
+
+	c->r2t_pdu = page_frag_alloc(&queue->pf_cache,
+			sizeof(*c->r2t_pdu) + hdgst, GFP_KERNEL | __GFP_ZERO);
+	if (!c->r2t_pdu)
+		goto out_free_data;
+
+	c->recv_msg.msg_flags = MSG_DONTWAIT | MSG_NOSIGNAL;
+
+	list_add_tail(&c->entry, &queue->free_list);
+
+	return 0;
+out_free_data:
+	page_frag_free(c->data_pdu);
+out_free_rsp:
+	page_frag_free(c->rsp_pdu);
+out_free_cmd:
+	page_frag_free(c->cmd_pdu);
+	return -ENOMEM;
+}
+
+static void nvmet_tcp_free_cmd(struct nvmet_tcp_cmd *c)
+{
+	page_frag_free(c->r2t_pdu);
+	page_frag_free(c->data_pdu);
+	page_frag_free(c->rsp_pdu);
+	page_frag_free(c->cmd_pdu);
+}
+
+static int nvmet_tcp_alloc_cmds(struct nvmet_tcp_queue *queue)
+{
+	struct nvmet_tcp_cmd *cmds;
+	int i, ret = -EINVAL, nr_cmds = queue->nr_cmds;
+
+	cmds = kcalloc(nr_cmds, sizeof(struct nvmet_tcp_cmd), GFP_KERNEL);
+	if (!cmds)
+		goto out;
+
+	for (i = 0; i < nr_cmds; i++) {
+		ret = nvmet_tcp_alloc_cmd(queue, cmds + i);
+		if (ret)
+			goto out_free;
+	}
+
+	queue->cmds = cmds;
+
+	return 0;
+out_free:
+	while (--i >= 0)
+		nvmet_tcp_free_cmd(cmds + i);
+	kfree(cmds);
+out:
+	return ret;
+}
+
+static void nvmet_tcp_free_cmds(struct nvmet_tcp_queue *queue)
+{
+	struct nvmet_tcp_cmd *cmds = queue->cmds;
+	int i;
+
+	for (i = 0; i < queue->nr_cmds; i++)
+		nvmet_tcp_free_cmd(cmds + i);
+
+	nvmet_tcp_free_cmd(&queue->connect);
+	kfree(cmds);
+}
+
+static void nvmet_tcp_restore_socket_callbacks(struct nvmet_tcp_queue *queue)
+{
+	struct socket *sock = queue->sock;
+
+	write_lock_bh(&sock->sk->sk_callback_lock);
+	sock->sk->sk_data_ready =  queue->data_ready;
+	sock->sk->sk_state_change = queue->state_change;
+	sock->sk->sk_write_space = queue->write_space;
+	sock->sk->sk_user_data = NULL;
+	write_unlock_bh(&sock->sk->sk_callback_lock);
+}
+
+static void nvmet_tcp_uninit_data_in_cmds(struct nvmet_tcp_queue *queue)
+{
+	struct nvmet_tcp_cmd *cmd = queue->cmds;
+	int i;
+
+	for (i = 0; i < queue->nr_cmds; i++, cmd++) {
+		if (nvmet_tcp_need_data_in(cmd))
+			nvmet_req_uninit(&cmd->req);
+	}
+
+	if (!queue->nr_cmds && nvmet_tcp_need_data_in(&queue->connect)) {
+		/* failed in connect */
+		nvmet_req_uninit(&queue->connect.req);
+	}
+}
+
+static void nvmet_tcp_free_cmd_data_in_buffers(struct nvmet_tcp_queue *queue)
+{
+	struct nvmet_tcp_cmd *cmd = queue->cmds;
+	int i;
+
+	for (i = 0; i < queue->nr_cmds; i++, cmd++) {
+		if (nvmet_tcp_need_data_in(cmd))
+			nvmet_tcp_free_cmd_buffers(cmd);
+	}
+
+	if (!queue->nr_cmds && nvmet_tcp_need_data_in(&queue->connect))
+		nvmet_tcp_free_cmd_buffers(&queue->connect);
+}
+
+static void nvmet_tcp_release_queue_work(struct work_struct *w)
+{
+	struct page *page;
+	struct nvmet_tcp_queue *queue =
+		container_of(w, struct nvmet_tcp_queue, release_work);
+
+	mutex_lock(&nvmet_tcp_queue_mutex);
+	list_del_init(&queue->queue_list);
+	mutex_unlock(&nvmet_tcp_queue_mutex);
+
+	nvmet_tcp_restore_socket_callbacks(queue);
+	cancel_work_sync(&queue->io_work);
+	/* stop accepting incoming data */
+	queue->rcv_state = NVMET_TCP_RECV_ERR;
+
+	nvmet_tcp_uninit_data_in_cmds(queue);
+	nvmet_sq_destroy(&queue->nvme_sq);
+	cancel_work_sync(&queue->io_work);
+	nvmet_tcp_free_cmd_data_in_buffers(queue);
+	sock_release(queue->sock);
+	nvmet_tcp_free_cmds(queue);
+	if (queue->hdr_digest || queue->data_digest)
+		nvmet_tcp_free_crypto(queue);
+	ida_free(&nvmet_tcp_queue_ida, queue->idx);
+
+	page = virt_to_head_page(queue->pf_cache.va);
+	__page_frag_cache_drain(page, queue->pf_cache.pagecnt_bias);
+	kfree(queue);
+}
+
+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 (likely(queue))
+		queue_work_on(queue_cpu(queue), nvmet_tcp_wq, &queue->io_work);
+	read_unlock_bh(&sk->sk_callback_lock);
+}
+
+static void nvmet_tcp_write_space(struct sock *sk)
+{
+	struct nvmet_tcp_queue *queue;
+
+	read_lock_bh(&sk->sk_callback_lock);
+	queue = sk->sk_user_data;
+	if (unlikely(!queue))
+		goto out;
+
+	if (unlikely(queue->state == NVMET_TCP_Q_CONNECTING)) {
+		queue->write_space(sk);
+		goto out;
+	}
+
+	if (sk_stream_is_writeable(sk)) {
+		clear_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
+		queue_work_on(queue_cpu(queue), nvmet_tcp_wq, &queue->io_work);
+	}
+out:
+	read_unlock_bh(&sk->sk_callback_lock);
+}
+
+static void nvmet_tcp_state_change(struct sock *sk)
+{
+	struct nvmet_tcp_queue *queue;
+
+	read_lock_bh(&sk->sk_callback_lock);
+	queue = sk->sk_user_data;
+	if (!queue)
+		goto done;
+
+	switch (sk->sk_state) {
+	case TCP_FIN_WAIT2:
+	case TCP_LAST_ACK:
+		break;
+	case TCP_FIN_WAIT1:
+	case TCP_CLOSE_WAIT:
+	case TCP_CLOSE:
+		/* FALLTHRU */
+		nvmet_tcp_schedule_release_queue(queue);
+		break;
+	default:
+		pr_warn("queue %d unhandled state %d\n",
+			queue->idx, sk->sk_state);
+	}
+done:
+	read_unlock_bh(&sk->sk_callback_lock);
+}
+
+static int nvmet_tcp_set_queue_sock(struct nvmet_tcp_queue *queue)
+{
+	struct socket *sock = queue->sock;
+	struct inet_sock *inet = inet_sk(sock->sk);
+	int ret;
+
+	ret = kernel_getsockname(sock,
+		(struct sockaddr *)&queue->sockaddr);
+	if (ret < 0)
+		return ret;
+
+	ret = kernel_getpeername(sock,
+		(struct sockaddr *)&queue->sockaddr_peer);
+	if (ret < 0)
+		return ret;
+
+	/*
+	 * Cleanup whatever is sitting in the TCP transmit queue on socket
+	 * close. This is done to prevent stale data from being sent should
+	 * the network connection be restored before TCP times out.
+	 */
+	sock_no_linger(sock->sk);
+
+	if (so_priority > 0)
+		sock_set_priority(sock->sk, so_priority);
+
+	/* Set socket type of service */
+	if (inet->rcv_tos > 0)
+		ip_sock_set_tos(sock->sk, inet->rcv_tos);
+
+	ret = 0;
+	write_lock_bh(&sock->sk->sk_callback_lock);
+	if (sock->sk->sk_state != TCP_ESTABLISHED) {
+		/*
+		 * If the socket is already closing, don't even start
+		 * consuming it
+		 */
+		ret = -ENOTCONN;
+	} else {
+		sock->sk->sk_user_data = queue;
+		queue->data_ready = sock->sk->sk_data_ready;
+		sock->sk->sk_data_ready = nvmet_tcp_data_ready;
+		queue->state_change = sock->sk->sk_state_change;
+		sock->sk->sk_state_change = nvmet_tcp_state_change;
+		queue->write_space = sock->sk->sk_write_space;
+		sock->sk->sk_write_space = nvmet_tcp_write_space;
+		if (idle_poll_period_usecs)
+			nvmet_tcp_arm_queue_deadline(queue);
+		queue_work_on(queue_cpu(queue), nvmet_tcp_wq, &queue->io_work);
+	}
+	write_unlock_bh(&sock->sk->sk_callback_lock);
+
+	return ret;
+}
+
+static int nvmet_tcp_alloc_queue(struct nvmet_tcp_port *port,
+		struct socket *newsock)
+{
+	struct nvmet_tcp_queue *queue;
+	int ret;
+
+	queue = kzalloc(sizeof(*queue), GFP_KERNEL);
+	if (!queue)
+		return -ENOMEM;
+
+	INIT_WORK(&queue->release_work, nvmet_tcp_release_queue_work);
+	INIT_WORK(&queue->io_work, nvmet_tcp_io_work);
+	queue->sock = newsock;
+	queue->port = port;
+	queue->nr_cmds = 0;
+	spin_lock_init(&queue->state_lock);
+	queue->state = NVMET_TCP_Q_CONNECTING;
+	INIT_LIST_HEAD(&queue->free_list);
+	init_llist_head(&queue->resp_list);
+	INIT_LIST_HEAD(&queue->resp_send_list);
+
+	queue->idx = ida_alloc(&nvmet_tcp_queue_ida, GFP_KERNEL);
+	if (queue->idx < 0) {
+		ret = queue->idx;
+		goto out_free_queue;
+	}
+
+	ret = nvmet_tcp_alloc_cmd(queue, &queue->connect);
+	if (ret)
+		goto out_ida_remove;
+
+	ret = nvmet_sq_init(&queue->nvme_sq);
+	if (ret)
+		goto out_free_connect;
+
+	nvmet_prepare_receive_pdu(queue);
+
+	mutex_lock(&nvmet_tcp_queue_mutex);
+	list_add_tail(&queue->queue_list, &nvmet_tcp_queue_list);
+	mutex_unlock(&nvmet_tcp_queue_mutex);
+
+	ret = nvmet_tcp_set_queue_sock(queue);
+	if (ret)
+		goto out_destroy_sq;
+
+	return 0;
+out_destroy_sq:
+	mutex_lock(&nvmet_tcp_queue_mutex);
+	list_del_init(&queue->queue_list);
+	mutex_unlock(&nvmet_tcp_queue_mutex);
+	nvmet_sq_destroy(&queue->nvme_sq);
+out_free_connect:
+	nvmet_tcp_free_cmd(&queue->connect);
+out_ida_remove:
+	ida_free(&nvmet_tcp_queue_ida, queue->idx);
+out_free_queue:
+	kfree(queue);
+	return ret;
+}
+
+static void nvmet_tcp_accept_work(struct work_struct *w)
+{
+	struct nvmet_tcp_port *port =
+		container_of(w, struct nvmet_tcp_port, accept_work);
+	struct socket *newsock;
+	int ret;
+
+	while (true) {
+		ret = kernel_accept(port->sock, &newsock, O_NONBLOCK);
+		if (ret < 0) {
+			if (ret != -EAGAIN)
+				pr_warn("failed to accept err=%d\n", ret);
+			return;
+		}
+		ret = nvmet_tcp_alloc_queue(port, newsock);
+		if (ret) {
+			pr_err("failed to allocate queue\n");
+			sock_release(newsock);
+		}
+	}
+}
+
+static void nvmet_tcp_listen_data_ready(struct sock *sk)
+{
+	struct nvmet_tcp_port *port;
+
+	read_lock_bh(&sk->sk_callback_lock);
+	port = sk->sk_user_data;
+	if (!port)
+		goto out;
+
+	if (sk->sk_state == TCP_LISTEN)
+		queue_work(nvmet_wq, &port->accept_work);
+out:
+	read_unlock_bh(&sk->sk_callback_lock);
+}
+
+static int nvmet_tcp_add_port(struct nvmet_port *nport)
+{
+	struct nvmet_tcp_port *port;
+	__kernel_sa_family_t af;
+	int ret;
+
+	port = kzalloc(sizeof(*port), GFP_KERNEL);
+	if (!port)
+		return -ENOMEM;
+
+	switch (nport->disc_addr.adrfam) {
+	case NVMF_ADDR_FAMILY_IP4:
+		af = AF_INET;
+		break;
+	case NVMF_ADDR_FAMILY_IP6:
+		af = AF_INET6;
+		break;
+	default:
+		pr_err("address family %d not supported\n",
+				nport->disc_addr.adrfam);
+		ret = -EINVAL;
+		goto err_port;
+	}
+
+	ret = inet_pton_with_scope(&init_net, af, nport->disc_addr.traddr,
+			nport->disc_addr.trsvcid, &port->addr);
+	if (ret) {
+		pr_err("malformed ip/port passed: %s:%s\n",
+			nport->disc_addr.traddr, nport->disc_addr.trsvcid);
+		goto err_port;
+	}
+
+	port->nport = nport;
+	INIT_WORK(&port->accept_work, nvmet_tcp_accept_work);
+	if (port->nport->inline_data_size < 0)
+		port->nport->inline_data_size = NVMET_TCP_DEF_INLINE_DATA_SIZE;
+
+	ret = sock_create(port->addr.ss_family, SOCK_STREAM,
+				IPPROTO_TCP, &port->sock);
+	if (ret) {
+		pr_err("failed to create a socket\n");
+		goto err_port;
+	}
+
+	port->sock->sk->sk_user_data = port;
+	port->data_ready = port->sock->sk->sk_data_ready;
+	port->sock->sk->sk_data_ready = nvmet_tcp_listen_data_ready;
+	sock_set_reuseaddr(port->sock->sk);
+	tcp_sock_set_nodelay(port->sock->sk);
+	if (so_priority > 0)
+		sock_set_priority(port->sock->sk, so_priority);
+
+	ret = kernel_bind(port->sock, (struct sockaddr *)&port->addr,
+			sizeof(port->addr));
+	if (ret) {
+		pr_err("failed to bind port socket %d\n", ret);
+		goto err_sock;
+	}
+
+	ret = kernel_listen(port->sock, 128);
+	if (ret) {
+		pr_err("failed to listen %d on port sock\n", ret);
+		goto err_sock;
+	}
+
+	nport->priv = port;
+	pr_info("enabling port %d (%pISpc)\n",
+		le16_to_cpu(nport->disc_addr.portid), &port->addr);
+
+	return 0;
+
+err_sock:
+	sock_release(port->sock);
+err_port:
+	kfree(port);
+	return ret;
+}
+
+static void nvmet_tcp_destroy_port_queues(struct nvmet_tcp_port *port)
+{
+	struct nvmet_tcp_queue *queue;
+
+	mutex_lock(&nvmet_tcp_queue_mutex);
+	list_for_each_entry(queue, &nvmet_tcp_queue_list, queue_list)
+		if (queue->port == port)
+			kernel_sock_shutdown(queue->sock, SHUT_RDWR);
+	mutex_unlock(&nvmet_tcp_queue_mutex);
+}
+
+static void nvmet_tcp_remove_port(struct nvmet_port *nport)
+{
+	struct nvmet_tcp_port *port = nport->priv;
+
+	write_lock_bh(&port->sock->sk->sk_callback_lock);
+	port->sock->sk->sk_data_ready = port->data_ready;
+	port->sock->sk->sk_user_data = NULL;
+	write_unlock_bh(&port->sock->sk->sk_callback_lock);
+	cancel_work_sync(&port->accept_work);
+	/*
+	 * Destroy the remaining queues, which are not belong to any
+	 * controller yet.
+	 */
+	nvmet_tcp_destroy_port_queues(port);
+
+	sock_release(port->sock);
+	kfree(port);
+}
+
+static void nvmet_tcp_delete_ctrl(struct nvmet_ctrl *ctrl)
+{
+	struct nvmet_tcp_queue *queue;
+
+	mutex_lock(&nvmet_tcp_queue_mutex);
+	list_for_each_entry(queue, &nvmet_tcp_queue_list, queue_list)
+		if (queue->nvme_sq.ctrl == ctrl)
+			kernel_sock_shutdown(queue->sock, SHUT_RDWR);
+	mutex_unlock(&nvmet_tcp_queue_mutex);
+}
+
+static u16 nvmet_tcp_install_queue(struct nvmet_sq *sq)
+{
+	struct nvmet_tcp_queue *queue =
+		container_of(sq, struct nvmet_tcp_queue, nvme_sq);
+
+	if (sq->qid == 0) {
+		/* Let inflight controller teardown complete */
+		flush_workqueue(nvmet_wq);
+	}
+
+	queue->nr_cmds = sq->size * 2;
+	if (nvmet_tcp_alloc_cmds(queue))
+		return NVME_SC_INTERNAL;
+	return 0;
+}
+
+static void nvmet_tcp_disc_port_addr(struct nvmet_req *req,
+		struct nvmet_port *nport, char *traddr)
+{
+	struct nvmet_tcp_port *port = nport->priv;
+
+	if (inet_addr_is_any((struct sockaddr *)&port->addr)) {
+		struct nvmet_tcp_cmd *cmd =
+			container_of(req, struct nvmet_tcp_cmd, req);
+		struct nvmet_tcp_queue *queue = cmd->queue;
+
+		sprintf(traddr, "%pISc", (struct sockaddr *)&queue->sockaddr);
+	} else {
+		memcpy(traddr, nport->disc_addr.traddr, NVMF_TRADDR_SIZE);
+	}
+}
+
+static const struct nvmet_fabrics_ops nvmet_tcp_ops = {
+	.owner			= THIS_MODULE,
+	.type			= NVMF_TRTYPE_TCP,
+	.msdbd			= 1,
+	.add_port		= nvmet_tcp_add_port,
+	.remove_port		= nvmet_tcp_remove_port,
+	.queue_response		= nvmet_tcp_queue_response,
+	.delete_ctrl		= nvmet_tcp_delete_ctrl,
+	.install_queue		= nvmet_tcp_install_queue,
+	.disc_traddr		= nvmet_tcp_disc_port_addr,
+};
+
+static int __init nvmet_tcp_init(void)
+{
+	int ret;
+
+	nvmet_tcp_wq = alloc_workqueue("nvmet_tcp_wq",
+				WQ_MEM_RECLAIM | WQ_HIGHPRI, 0);
+	if (!nvmet_tcp_wq)
+		return -ENOMEM;
+
+	ret = nvmet_register_transport(&nvmet_tcp_ops);
+	if (ret)
+		goto err;
+
+	return 0;
+err:
+	destroy_workqueue(nvmet_tcp_wq);
+	return ret;
+}
+
+static void __exit nvmet_tcp_exit(void)
+{
+	struct nvmet_tcp_queue *queue;
+
+	nvmet_unregister_transport(&nvmet_tcp_ops);
+
+	flush_workqueue(nvmet_wq);
+	mutex_lock(&nvmet_tcp_queue_mutex);
+	list_for_each_entry(queue, &nvmet_tcp_queue_list, queue_list)
+		kernel_sock_shutdown(queue->sock, SHUT_RDWR);
+	mutex_unlock(&nvmet_tcp_queue_mutex);
+	flush_workqueue(nvmet_wq);
+
+	destroy_workqueue(nvmet_tcp_wq);
+}
+
+module_init(nvmet_tcp_init);
+module_exit(nvmet_tcp_exit);
+
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("nvmet-transport-3"); /* 3 == NVMF_TRTYPE_TCP */