drivers/nvme/target/discovery.c - third_party/linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*
  * Discovery service for the NVMe over Fabrics target.
  * Copyright (C) 2016 Intel Corporation. All rights reserved.
  */
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 #include <linux/slab.h>
 #include <generated/utsrelease.h>
 #include "nvmet.h"

 struct nvmet_subsys *nvmet_disc_subsys;

 static u64 nvmet_genctr;

 static void __nvmet_disc_changed(struct nvmet_port *port,
 				 struct nvmet_ctrl *ctrl)
 {
 	if (ctrl->port != port)
 		return;

 	if (nvmet_aen_bit_disabled(ctrl, NVME_AEN_BIT_DISC_CHANGE))
 		return;

 	nvmet_add_async_event(ctrl, NVME_AER_TYPE_NOTICE,
 			      NVME_AER_NOTICE_DISC_CHANGED, NVME_LOG_DISC);
 }

 void nvmet_port_disc_changed(struct nvmet_port *port,
 			     struct nvmet_subsys *subsys)
 {
 	struct nvmet_ctrl *ctrl;

 	lockdep_assert_held(&nvmet_config_sem);
 	nvmet_genctr++;

 	mutex_lock(&nvmet_disc_subsys->lock);
 	list_for_each_entry(ctrl, &nvmet_disc_subsys->ctrls, subsys_entry) {
 		if (subsys && !nvmet_host_allowed(subsys, ctrl->hostnqn))
 			continue;

 		__nvmet_disc_changed(port, ctrl);
 	}
 	mutex_unlock(&nvmet_disc_subsys->lock);

 	/* If transport can signal change, notify transport */
 	if (port->tr_ops && port->tr_ops->discovery_chg)
 		port->tr_ops->discovery_chg(port);
 }

 static void __nvmet_subsys_disc_changed(struct nvmet_port *port,
 					struct nvmet_subsys *subsys,
 					struct nvmet_host *host)
 {
 	struct nvmet_ctrl *ctrl;

 	mutex_lock(&nvmet_disc_subsys->lock);
 	list_for_each_entry(ctrl, &nvmet_disc_subsys->ctrls, subsys_entry) {
 		if (host && strcmp(nvmet_host_name(host), ctrl->hostnqn))
 			continue;

 		__nvmet_disc_changed(port, ctrl);
 	}
 	mutex_unlock(&nvmet_disc_subsys->lock);
 }

 void nvmet_subsys_disc_changed(struct nvmet_subsys *subsys,
 			       struct nvmet_host *host)
 {
 	struct nvmet_port *port;
 	struct nvmet_subsys_link *s;

 	lockdep_assert_held(&nvmet_config_sem);
 	nvmet_genctr++;

 	list_for_each_entry(port, nvmet_ports, global_entry)
 		list_for_each_entry(s, &port->subsystems, entry) {
 			if (s->subsys != subsys)
 				continue;
 			__nvmet_subsys_disc_changed(port, subsys, host);
 		}
 }

 void nvmet_referral_enable(struct nvmet_port *parent, struct nvmet_port *port)
 {
 	down_write(&nvmet_config_sem);
 	if (list_empty(&port->entry)) {
 		list_add_tail(&port->entry, &parent->referrals);
 		port->enabled = true;
 		nvmet_port_disc_changed(parent, NULL);
 	}
 	up_write(&nvmet_config_sem);
 }

 void nvmet_referral_disable(struct nvmet_port *parent, struct nvmet_port *port)
 {
 	down_write(&nvmet_config_sem);
 	if (!list_empty(&port->entry)) {
 		port->enabled = false;
 		list_del_init(&port->entry);
 		nvmet_port_disc_changed(parent, NULL);
 	}
 	up_write(&nvmet_config_sem);
 }

 static void nvmet_format_discovery_entry(struct nvmf_disc_rsp_page_hdr *hdr,
 		struct nvmet_port *port, char *subsys_nqn, char *traddr,
 		u8 type, u32 numrec)
 {
 	struct nvmf_disc_rsp_page_entry *e = &hdr->entries[numrec];

 	e->trtype = port->disc_addr.trtype;
 	e->adrfam = port->disc_addr.adrfam;
 	e->treq = port->disc_addr.treq;
 	e->portid = port->disc_addr.portid;
 	/* we support only dynamic controllers */
 	e->cntlid = cpu_to_le16(NVME_CNTLID_DYNAMIC);
 	e->asqsz = cpu_to_le16(NVME_AQ_DEPTH);
 	e->subtype = type;
 	memcpy(e->trsvcid, port->disc_addr.trsvcid, NVMF_TRSVCID_SIZE);
 	memcpy(e->traddr, traddr, NVMF_TRADDR_SIZE);
 	memcpy(e->tsas.common, port->disc_addr.tsas.common, NVMF_TSAS_SIZE);
 	strncpy(e->subnqn, subsys_nqn, NVMF_NQN_SIZE);
 }

 /*
  * nvmet_set_disc_traddr - set a correct discovery log entry traddr
  *
  * IP based transports (e.g RDMA) can listen on "any" ipv4/ipv6 addresses
  * (INADDR_ANY or IN6ADDR_ANY_INIT). The discovery log page traddr reply
  * must not contain that "any" IP address. If the transport implements
  * .disc_traddr, use it. this callback will set the discovery traddr
  * from the req->port address in case the port in question listens
  * "any" IP address.
  */
 static void nvmet_set_disc_traddr(struct nvmet_req *req, struct nvmet_port *port,
 		char *traddr)
 {
 	if (req->ops->disc_traddr)
 		req->ops->disc_traddr(req, port, traddr);
 	else
 		memcpy(traddr, port->disc_addr.traddr, NVMF_TRADDR_SIZE);
 }

 static size_t discovery_log_entries(struct nvmet_req *req)
 {
 	struct nvmet_ctrl *ctrl = req->sq->ctrl;
 	struct nvmet_subsys_link *p;
 	struct nvmet_port *r;
 	size_t entries = 1;

 	list_for_each_entry(p, &req->port->subsystems, entry) {
 		if (!nvmet_host_allowed(p->subsys, ctrl->hostnqn))
 			continue;
 		entries++;
 	}
 	list_for_each_entry(r, &req->port->referrals, entry)
 		entries++;
 	return entries;
 }

 static void nvmet_execute_disc_get_log_page(struct nvmet_req *req)
 {
 	const int entry_size = sizeof(struct nvmf_disc_rsp_page_entry);
 	struct nvmet_ctrl *ctrl = req->sq->ctrl;
 	struct nvmf_disc_rsp_page_hdr *hdr;
 	u64 offset = nvmet_get_log_page_offset(req->cmd);
 	size_t data_len = nvmet_get_log_page_len(req->cmd);
 	size_t alloc_len;
 	struct nvmet_subsys_link *p;
 	struct nvmet_port *r;
 	u32 numrec = 0;
 	u16 status = 0;
 	void *buffer;
 	char traddr[NVMF_TRADDR_SIZE];

 	if (!nvmet_check_transfer_len(req, data_len))
 		return;

 	if (req->cmd->get_log_page.lid != NVME_LOG_DISC) {
 		req->error_loc =
 			offsetof(struct nvme_get_log_page_command, lid);
 		status = NVME_SC_INVALID_FIELD | NVME_SC_DNR;
 		goto out;
 	}

 	/* Spec requires dword aligned offsets */
 	if (offset & 0x3) {
 		req->error_loc =
 			offsetof(struct nvme_get_log_page_command, lpo);
 		status = NVME_SC_INVALID_FIELD | NVME_SC_DNR;
 		goto out;
 	}

 	/*
 	 * Make sure we're passing at least a buffer of response header size.
 	 * If host provided data len is less than the header size, only the
 	 * number of bytes requested by host will be sent to host.
 	 */
 	down_read(&nvmet_config_sem);
 	alloc_len = sizeof(*hdr) + entry_size * discovery_log_entries(req);
 	buffer = kzalloc(alloc_len, GFP_KERNEL);
 	if (!buffer) {
 		up_read(&nvmet_config_sem);
 		status = NVME_SC_INTERNAL;
 		goto out;
 	}
 	hdr = buffer;

 	nvmet_set_disc_traddr(req, req->port, traddr);

 	nvmet_format_discovery_entry(hdr, req->port,
 				     nvmet_disc_subsys->subsysnqn,
 				     traddr, NVME_NQN_CURR, numrec);
 	numrec++;

 	list_for_each_entry(p, &req->port->subsystems, entry) {
 		if (!nvmet_host_allowed(p->subsys, ctrl->hostnqn))
 			continue;

 		nvmet_format_discovery_entry(hdr, req->port,
 				p->subsys->subsysnqn, traddr,
 				NVME_NQN_NVME, numrec);
 		numrec++;
 	}

 	list_for_each_entry(r, &req->port->referrals, entry) {
 		nvmet_format_discovery_entry(hdr, r,
 				NVME_DISC_SUBSYS_NAME,
 				r->disc_addr.traddr,
 				NVME_NQN_DISC, numrec);
 		numrec++;
 	}

 	hdr->genctr = cpu_to_le64(nvmet_genctr);
 	hdr->numrec = cpu_to_le64(numrec);
 	hdr->recfmt = cpu_to_le16(0);

 	nvmet_clear_aen_bit(req, NVME_AEN_BIT_DISC_CHANGE);

 	up_read(&nvmet_config_sem);

 	status = nvmet_copy_to_sgl(req, 0, buffer + offset, data_len);
 	kfree(buffer);
 out:
 	nvmet_req_complete(req, status);
 }

 static void nvmet_execute_disc_identify(struct nvmet_req *req)
 {
 	struct nvmet_ctrl *ctrl = req->sq->ctrl;
 	struct nvme_id_ctrl *id;
 	u16 status = 0;

 	if (!nvmet_check_transfer_len(req, NVME_IDENTIFY_DATA_SIZE))
 		return;

 	if (req->cmd->identify.cns != NVME_ID_CNS_CTRL) {
 		req->error_loc = offsetof(struct nvme_identify, cns);
 		status = NVME_SC_INVALID_FIELD | NVME_SC_DNR;
 		goto out;
 	}

 	id = kzalloc(sizeof(*id), GFP_KERNEL);
 	if (!id) {
 		status = NVME_SC_INTERNAL;
 		goto out;
 	}

 	memcpy(id->sn, ctrl->subsys->serial, NVMET_SN_MAX_SIZE);
 	memset(id->fr, ' ', sizeof(id->fr));
 	memcpy_and_pad(id->mn, sizeof(id->mn), ctrl->subsys->model_number,
 		       strlen(ctrl->subsys->model_number), ' ');
 	memcpy_and_pad(id->fr, sizeof(id->fr),
 		       UTS_RELEASE, strlen(UTS_RELEASE), ' ');

 	id->cntrltype = NVME_CTRL_DISC;

 	/* no limit on data transfer sizes for now */
 	id->mdts = 0;
 	id->cntlid = cpu_to_le16(ctrl->cntlid);
 	id->ver = cpu_to_le32(ctrl->subsys->ver);
 	id->lpa = (1 << 2);

 	/* no enforcement soft-limit for maxcmd - pick arbitrary high value */
 	id->maxcmd = cpu_to_le16(NVMET_MAX_CMD);

 	id->sgls = cpu_to_le32(1 << 0);	/* we always support SGLs */
 	if (ctrl->ops->flags & NVMF_KEYED_SGLS)
 		id->sgls |= cpu_to_le32(1 << 2);
 	if (req->port->inline_data_size)
 		id->sgls |= cpu_to_le32(1 << 20);

 	id->oaes = cpu_to_le32(NVMET_DISC_AEN_CFG_OPTIONAL);

 	strscpy(id->subnqn, ctrl->subsys->subsysnqn, sizeof(id->subnqn));

 	status = nvmet_copy_to_sgl(req, 0, id, sizeof(*id));

 	kfree(id);
 out:
 	nvmet_req_complete(req, status);
 }

 static void nvmet_execute_disc_set_features(struct nvmet_req *req)
 {
 	u32 cdw10 = le32_to_cpu(req->cmd->common.cdw10);
 	u16 stat;

 	if (!nvmet_check_transfer_len(req, 0))
 		return;

 	switch (cdw10 & 0xff) {
 	case NVME_FEAT_KATO:
 		stat = nvmet_set_feat_kato(req);
 		break;
 	case NVME_FEAT_ASYNC_EVENT:
 		stat = nvmet_set_feat_async_event(req,
 						  NVMET_DISC_AEN_CFG_OPTIONAL);
 		break;
 	default:
 		req->error_loc =
 			offsetof(struct nvme_common_command, cdw10);
 		stat = NVME_SC_INVALID_FIELD | NVME_SC_DNR;
 		break;
 	}

 	nvmet_req_complete(req, stat);
 }

 static void nvmet_execute_disc_get_features(struct nvmet_req *req)
 {
 	u32 cdw10 = le32_to_cpu(req->cmd->common.cdw10);
 	u16 stat = 0;

 	if (!nvmet_check_transfer_len(req, 0))
 		return;

 	switch (cdw10 & 0xff) {
 	case NVME_FEAT_KATO:
 		nvmet_get_feat_kato(req);
 		break;
 	case NVME_FEAT_ASYNC_EVENT:
 		nvmet_get_feat_async_event(req);
 		break;
 	default:
 		req->error_loc =
 			offsetof(struct nvme_common_command, cdw10);
 		stat = NVME_SC_INVALID_FIELD | NVME_SC_DNR;
 		break;
 	}

 	nvmet_req_complete(req, stat);
 }

 u16 nvmet_parse_discovery_cmd(struct nvmet_req *req)
 {
 	struct nvme_command *cmd = req->cmd;

 	if (unlikely(!(req->sq->ctrl->csts & NVME_CSTS_RDY))) {
 		pr_err("got cmd %d while not ready\n",
 		       cmd->common.opcode);
 		req->error_loc =
 			offsetof(struct nvme_common_command, opcode);
 		return NVME_SC_INVALID_OPCODE | NVME_SC_DNR;
 	}

 	switch (cmd->common.opcode) {
 	case nvme_admin_set_features:
 		req->execute = nvmet_execute_disc_set_features;
 		return 0;
 	case nvme_admin_get_features:
 		req->execute = nvmet_execute_disc_get_features;
 		return 0;
 	case nvme_admin_async_event:
 		req->execute = nvmet_execute_async_event;
 		return 0;
 	case nvme_admin_keep_alive:
 		req->execute = nvmet_execute_keep_alive;
 		return 0;
 	case nvme_admin_get_log_page:
 		req->execute = nvmet_execute_disc_get_log_page;
 		return 0;
 	case nvme_admin_identify:
 		req->execute = nvmet_execute_disc_identify;
 		return 0;
 	default:
 		pr_debug("unhandled cmd %d\n", cmd->common.opcode);
 		req->error_loc = offsetof(struct nvme_common_command, opcode);
 		return NVME_SC_INVALID_OPCODE | NVME_SC_DNR;
 	}

 }

 int __init nvmet_init_discovery(void)
 {
 	nvmet_disc_subsys =
 		nvmet_subsys_alloc(NVME_DISC_SUBSYS_NAME, NVME_NQN_CURR);
 	return PTR_ERR_OR_ZERO(nvmet_disc_subsys);
 }

 void nvmet_exit_discovery(void)
 {
 	nvmet_subsys_put(nvmet_disc_subsys);
 }
	// SPDX-License-Identifier: GPL-2.0
	/*
	* Discovery service for the NVMe over Fabrics target.
	* Copyright (C) 2016 Intel Corporation. All rights reserved.
	*/
	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
	#include <linux/slab.h>
	#include <generated/utsrelease.h>
	#include "nvmet.h"

	struct nvmet_subsys *nvmet_disc_subsys;

	static u64 nvmet_genctr;

	static void __nvmet_disc_changed(struct nvmet_port *port,
	struct nvmet_ctrl *ctrl)
	{
	if (ctrl->port != port)
	return;

	if (nvmet_aen_bit_disabled(ctrl, NVME_AEN_BIT_DISC_CHANGE))
	return;

	nvmet_add_async_event(ctrl, NVME_AER_TYPE_NOTICE,
	NVME_AER_NOTICE_DISC_CHANGED, NVME_LOG_DISC);
	}

	void nvmet_port_disc_changed(struct nvmet_port *port,
	struct nvmet_subsys *subsys)
	{
	struct nvmet_ctrl *ctrl;

	lockdep_assert_held(&nvmet_config_sem);
	nvmet_genctr++;

	mutex_lock(&nvmet_disc_subsys->lock);
	list_for_each_entry(ctrl, &nvmet_disc_subsys->ctrls, subsys_entry) {
	if (subsys && !nvmet_host_allowed(subsys, ctrl->hostnqn))
	continue;

	__nvmet_disc_changed(port, ctrl);
	}
	mutex_unlock(&nvmet_disc_subsys->lock);

	/* If transport can signal change, notify transport */
	if (port->tr_ops && port->tr_ops->discovery_chg)
	port->tr_ops->discovery_chg(port);
	}

	static void __nvmet_subsys_disc_changed(struct nvmet_port *port,
	struct nvmet_subsys *subsys,
	struct nvmet_host *host)
	{
	struct nvmet_ctrl *ctrl;

	mutex_lock(&nvmet_disc_subsys->lock);
	list_for_each_entry(ctrl, &nvmet_disc_subsys->ctrls, subsys_entry) {
	if (host && strcmp(nvmet_host_name(host), ctrl->hostnqn))
	continue;

	__nvmet_disc_changed(port, ctrl);
	}
	mutex_unlock(&nvmet_disc_subsys->lock);
	}

	void nvmet_subsys_disc_changed(struct nvmet_subsys *subsys,
	struct nvmet_host *host)
	{
	struct nvmet_port *port;
	struct nvmet_subsys_link *s;

	lockdep_assert_held(&nvmet_config_sem);
	nvmet_genctr++;

	list_for_each_entry(port, nvmet_ports, global_entry)
	list_for_each_entry(s, &port->subsystems, entry) {
	if (s->subsys != subsys)
	continue;
	__nvmet_subsys_disc_changed(port, subsys, host);
	}
	}

	void nvmet_referral_enable(struct nvmet_port parent, struct nvmet_port port)
	{
	down_write(&nvmet_config_sem);
	if (list_empty(&port->entry)) {
	list_add_tail(&port->entry, &parent->referrals);
	port->enabled = true;
	nvmet_port_disc_changed(parent, NULL);
	}
	up_write(&nvmet_config_sem);
	}

	void nvmet_referral_disable(struct nvmet_port parent, struct nvmet_port port)
	{
	down_write(&nvmet_config_sem);
	if (!list_empty(&port->entry)) {
	port->enabled = false;
	list_del_init(&port->entry);
	nvmet_port_disc_changed(parent, NULL);
	}
	up_write(&nvmet_config_sem);
	}

	static void nvmet_format_discovery_entry(struct nvmf_disc_rsp_page_hdr *hdr,
	struct nvmet_port port, char subsys_nqn, char *traddr,
	u8 type, u32 numrec)
	{
	struct nvmf_disc_rsp_page_entry *e = &hdr->entries[numrec];

	e->trtype = port->disc_addr.trtype;
	e->adrfam = port->disc_addr.adrfam;
	e->treq = port->disc_addr.treq;
	e->portid = port->disc_addr.portid;
	/* we support only dynamic controllers */
	e->cntlid = cpu_to_le16(NVME_CNTLID_DYNAMIC);
	e->asqsz = cpu_to_le16(NVME_AQ_DEPTH);
	e->subtype = type;
	memcpy(e->trsvcid, port->disc_addr.trsvcid, NVMF_TRSVCID_SIZE);
	memcpy(e->traddr, traddr, NVMF_TRADDR_SIZE);
	memcpy(e->tsas.common, port->disc_addr.tsas.common, NVMF_TSAS_SIZE);
	strncpy(e->subnqn, subsys_nqn, NVMF_NQN_SIZE);
	}

	/*
	* nvmet_set_disc_traddr - set a correct discovery log entry traddr
	*
	* IP based transports (e.g RDMA) can listen on "any" ipv4/ipv6 addresses
	* (INADDR_ANY or IN6ADDR_ANY_INIT). The discovery log page traddr reply
	* must not contain that "any" IP address. If the transport implements
	* .disc_traddr, use it. this callback will set the discovery traddr
	* from the req->port address in case the port in question listens
	* "any" IP address.
	*/
	static void nvmet_set_disc_traddr(struct nvmet_req req, struct nvmet_port port,
	char *traddr)
	{
	if (req->ops->disc_traddr)
	req->ops->disc_traddr(req, port, traddr);
	else
	memcpy(traddr, port->disc_addr.traddr, NVMF_TRADDR_SIZE);
	}

	static size_t discovery_log_entries(struct nvmet_req *req)
	{
	struct nvmet_ctrl *ctrl = req->sq->ctrl;
	struct nvmet_subsys_link *p;
	struct nvmet_port *r;
	size_t entries = 1;

	list_for_each_entry(p, &req->port->subsystems, entry) {
	if (!nvmet_host_allowed(p->subsys, ctrl->hostnqn))
	continue;
	entries++;
	}
	list_for_each_entry(r, &req->port->referrals, entry)
	entries++;
	return entries;
	}

	static void nvmet_execute_disc_get_log_page(struct nvmet_req *req)
	{
	const int entry_size = sizeof(struct nvmf_disc_rsp_page_entry);
	struct nvmet_ctrl *ctrl = req->sq->ctrl;
	struct nvmf_disc_rsp_page_hdr *hdr;
	u64 offset = nvmet_get_log_page_offset(req->cmd);
	size_t data_len = nvmet_get_log_page_len(req->cmd);
	size_t alloc_len;
	struct nvmet_subsys_link *p;
	struct nvmet_port *r;
	u32 numrec = 0;
	u16 status = 0;
	void *buffer;
	char traddr[NVMF_TRADDR_SIZE];

	if (!nvmet_check_transfer_len(req, data_len))
	return;

	if (req->cmd->get_log_page.lid != NVME_LOG_DISC) {
	req->error_loc =
	offsetof(struct nvme_get_log_page_command, lid);
	status = NVME_SC_INVALID_FIELD \| NVME_SC_DNR;
	goto out;
	}

	/* Spec requires dword aligned offsets */
	if (offset & 0x3) {
	req->error_loc =
	offsetof(struct nvme_get_log_page_command, lpo);
	status = NVME_SC_INVALID_FIELD \| NVME_SC_DNR;
	goto out;
	}

	/*
	* Make sure we're passing at least a buffer of response header size.
	* If host provided data len is less than the header size, only the
	* number of bytes requested by host will be sent to host.
	*/
	down_read(&nvmet_config_sem);
	alloc_len = sizeof(hdr) + entry_size discovery_log_entries(req);
	buffer = kzalloc(alloc_len, GFP_KERNEL);
	if (!buffer) {
	up_read(&nvmet_config_sem);
	status = NVME_SC_INTERNAL;
	goto out;
	}
	hdr = buffer;

	nvmet_set_disc_traddr(req, req->port, traddr);

	nvmet_format_discovery_entry(hdr, req->port,
	nvmet_disc_subsys->subsysnqn,
	traddr, NVME_NQN_CURR, numrec);
	numrec++;

	list_for_each_entry(p, &req->port->subsystems, entry) {
	if (!nvmet_host_allowed(p->subsys, ctrl->hostnqn))
	continue;

	nvmet_format_discovery_entry(hdr, req->port,
	p->subsys->subsysnqn, traddr,
	NVME_NQN_NVME, numrec);
	numrec++;
	}

	list_for_each_entry(r, &req->port->referrals, entry) {
	nvmet_format_discovery_entry(hdr, r,
	NVME_DISC_SUBSYS_NAME,
	r->disc_addr.traddr,
	NVME_NQN_DISC, numrec);
	numrec++;
	}

	hdr->genctr = cpu_to_le64(nvmet_genctr);
	hdr->numrec = cpu_to_le64(numrec);
	hdr->recfmt = cpu_to_le16(0);

	nvmet_clear_aen_bit(req, NVME_AEN_BIT_DISC_CHANGE);

	up_read(&nvmet_config_sem);

	status = nvmet_copy_to_sgl(req, 0, buffer + offset, data_len);
	kfree(buffer);
	out:
	nvmet_req_complete(req, status);
	}

	static void nvmet_execute_disc_identify(struct nvmet_req *req)
	{
	struct nvmet_ctrl *ctrl = req->sq->ctrl;
	struct nvme_id_ctrl *id;
	u16 status = 0;

	if (!nvmet_check_transfer_len(req, NVME_IDENTIFY_DATA_SIZE))
	return;

	if (req->cmd->identify.cns != NVME_ID_CNS_CTRL) {
	req->error_loc = offsetof(struct nvme_identify, cns);
	status = NVME_SC_INVALID_FIELD \| NVME_SC_DNR;
	goto out;
	}

	id = kzalloc(sizeof(*id), GFP_KERNEL);
	if (!id) {
	status = NVME_SC_INTERNAL;
	goto out;
	}

	memcpy(id->sn, ctrl->subsys->serial, NVMET_SN_MAX_SIZE);
	memset(id->fr, ' ', sizeof(id->fr));
	memcpy_and_pad(id->mn, sizeof(id->mn), ctrl->subsys->model_number,
	strlen(ctrl->subsys->model_number), ' ');
	memcpy_and_pad(id->fr, sizeof(id->fr),
	UTS_RELEASE, strlen(UTS_RELEASE), ' ');

	id->cntrltype = NVME_CTRL_DISC;

	/* no limit on data transfer sizes for now */
	id->mdts = 0;
	id->cntlid = cpu_to_le16(ctrl->cntlid);
	id->ver = cpu_to_le32(ctrl->subsys->ver);
	id->lpa = (1 << 2);

	/* no enforcement soft-limit for maxcmd - pick arbitrary high value */
	id->maxcmd = cpu_to_le16(NVMET_MAX_CMD);

	id->sgls = cpu_to_le32(1 << 0); /* we always support SGLs */
	if (ctrl->ops->flags & NVMF_KEYED_SGLS)
	id->sgls \|= cpu_to_le32(1 << 2);
	if (req->port->inline_data_size)
	id->sgls \|= cpu_to_le32(1 << 20);

	id->oaes = cpu_to_le32(NVMET_DISC_AEN_CFG_OPTIONAL);

	strscpy(id->subnqn, ctrl->subsys->subsysnqn, sizeof(id->subnqn));

	status = nvmet_copy_to_sgl(req, 0, id, sizeof(*id));

	kfree(id);
	out:
	nvmet_req_complete(req, status);
	}

	static void nvmet_execute_disc_set_features(struct nvmet_req *req)
	{
	u32 cdw10 = le32_to_cpu(req->cmd->common.cdw10);
	u16 stat;

	if (!nvmet_check_transfer_len(req, 0))
	return;

	switch (cdw10 & 0xff) {
	case NVME_FEAT_KATO:
	stat = nvmet_set_feat_kato(req);
	break;
	case NVME_FEAT_ASYNC_EVENT:
	stat = nvmet_set_feat_async_event(req,
	NVMET_DISC_AEN_CFG_OPTIONAL);
	break;
	default:
	req->error_loc =
	offsetof(struct nvme_common_command, cdw10);
	stat = NVME_SC_INVALID_FIELD \| NVME_SC_DNR;
	break;
	}

	nvmet_req_complete(req, stat);
	}

	static void nvmet_execute_disc_get_features(struct nvmet_req *req)
	{
	u32 cdw10 = le32_to_cpu(req->cmd->common.cdw10);
	u16 stat = 0;

	if (!nvmet_check_transfer_len(req, 0))
	return;

	switch (cdw10 & 0xff) {
	case NVME_FEAT_KATO:
	nvmet_get_feat_kato(req);
	break;
	case NVME_FEAT_ASYNC_EVENT:
	nvmet_get_feat_async_event(req);
	break;
	default:
	req->error_loc =
	offsetof(struct nvme_common_command, cdw10);
	stat = NVME_SC_INVALID_FIELD \| NVME_SC_DNR;
	break;
	}

	nvmet_req_complete(req, stat);
	}

	u16 nvmet_parse_discovery_cmd(struct nvmet_req *req)
	{
	struct nvme_command *cmd = req->cmd;

	if (unlikely(!(req->sq->ctrl->csts & NVME_CSTS_RDY))) {
	pr_err("got cmd %d while not ready\n",
	cmd->common.opcode);
	req->error_loc =
	offsetof(struct nvme_common_command, opcode);
	return NVME_SC_INVALID_OPCODE \| NVME_SC_DNR;
	}

	switch (cmd->common.opcode) {
	case nvme_admin_set_features:
	req->execute = nvmet_execute_disc_set_features;
	return 0;
	case nvme_admin_get_features:
	req->execute = nvmet_execute_disc_get_features;
	return 0;
	case nvme_admin_async_event:
	req->execute = nvmet_execute_async_event;
	return 0;
	case nvme_admin_keep_alive:
	req->execute = nvmet_execute_keep_alive;
	return 0;
	case nvme_admin_get_log_page:
	req->execute = nvmet_execute_disc_get_log_page;
	return 0;
	case nvme_admin_identify:
	req->execute = nvmet_execute_disc_identify;
	return 0;
	default:
	pr_debug("unhandled cmd %d\n", cmd->common.opcode);
	req->error_loc = offsetof(struct nvme_common_command, opcode);
	return NVME_SC_INVALID_OPCODE \| NVME_SC_DNR;
	}

	}

	int __init nvmet_init_discovery(void)
	{
	nvmet_disc_subsys =
	nvmet_subsys_alloc(NVME_DISC_SUBSYS_NAME, NVME_NQN_CURR);
	return PTR_ERR_OR_ZERO(nvmet_disc_subsys);
	}

	void nvmet_exit_discovery(void)
	{
	nvmet_subsys_put(nvmet_disc_subsys);
	}