ibft: separate ibft parsing from sysfs interface

Not all iscsi drivers support ibft. For drivers like be2iscsi
that do not but are bootable through a vendor firmware specific
format/process this patch moves the sysfs interface from the ibft code
to a lib module. This then allows userspace tools to search for iscsi boot
info in a common place and in a common format.

ibft iscsi boot info is exported in the same place as it was
before: /sys/firmware/ibft.

vendor/fw boot info gets export in /sys/firmware/iscsi_bootX, where X is the
scsi host number of the HBA. Underneath these parent dirs, the
target, ethernet, and initiator dirs are the same as they were before.

Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: Konrad Rzeszutek Wilk <konrad@kernel.org>
Signed-off-by: Peter Jones <pjones@redhat.com>

3 files changed, 490 insertions, 0 deletions

diff --git a/drivers/firmware/Kconfig b/drivers/firmware/Kconfig
index 1b03ba1d0834..571d2182613d 100644
--- a/drivers/firmware/Kconfig
+++ b/drivers/firmware/Kconfig
@@ -122,6 +122,14 @@ config ISCSI_IBFT_FIND
 	  is necessary for iSCSI Boot Firmware Table Attributes module to work
 	  properly.
 
+config ISCSI_BOOT_SYSFS
+	tristate "iSCSI Boot Sysfs Interface"
+	default	n
+	help
+	  This option enables support for exposing iSCSI boot information
+	  via sysfs to userspace. If you wish to export this information,
+	  say Y. Otherwise, say N.
+
 config ISCSI_IBFT
 	tristate "iSCSI Boot Firmware Table Attributes module"
 	depends on ISCSI_IBFT_FIND
diff --git a/drivers/firmware/Makefile b/drivers/firmware/Makefile
index 1c3c17343dbe..5fe7e1662922 100644
--- a/drivers/firmware/Makefile
+++ b/drivers/firmware/Makefile
@@ -10,4 +10,5 @@ obj-$(CONFIG_DCDBAS)		+= dcdbas.o
 obj-$(CONFIG_DMIID)		+= dmi-id.o
 obj-$(CONFIG_ISCSI_IBFT_FIND)	+= iscsi_ibft_find.o
 obj-$(CONFIG_ISCSI_IBFT)	+= iscsi_ibft.o
+obj-$(CONFIG_ISCSI_BOOT_SYSFS)	+= iscsi_boot_sysfs.o
 obj-$(CONFIG_FIRMWARE_MEMMAP)	+= memmap.o
diff --git a/drivers/firmware/iscsi_boot_sysfs.c b/drivers/firmware/iscsi_boot_sysfs.c
new file mode 100644
index 000000000000..df6bff7366cf
--- /dev/null
+++ b/drivers/firmware/iscsi_boot_sysfs.c
@@ -0,0 +1,481 @@
+/*
+ * Export the iSCSI boot info to userland via sysfs.
+ *
+ * Copyright (C) 2010 Red Hat, Inc.  All rights reserved.
+ * Copyright (C) 2010 Mike Christie
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License v2.0 as published by
+ * the Free Software Foundation
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/module.h>
+#include <linux/string.h>
+#include <linux/slab.h>
+#include <linux/sysfs.h>
+#include <linux/capability.h>
+#include <linux/iscsi_boot_sysfs.h>
+
+
+MODULE_AUTHOR("Mike Christie <michaelc@cs.wisc.edu>");
+MODULE_DESCRIPTION("sysfs interface and helpers to export iSCSI boot information");
+MODULE_LICENSE("GPL");
+/*
+ * The kobject and attribute structures.
+ */
+struct iscsi_boot_attr {
+	struct attribute attr;
+	int type;
+	ssize_t (*show) (void *data, int type, char *buf);
+};
+
+/*
+ * The routine called for all sysfs attributes.
+ */
+static ssize_t iscsi_boot_show_attribute(struct kobject *kobj,
+					 struct attribute *attr, char *buf)
+{
+	struct iscsi_boot_kobj *boot_kobj =
+			container_of(kobj, struct iscsi_boot_kobj, kobj);
+	struct iscsi_boot_attr *boot_attr =
+			container_of(attr, struct iscsi_boot_attr, attr);
+	ssize_t ret = -EIO;
+	char *str = buf;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EACCES;
+
+	if (boot_kobj->show)
+		ret = boot_kobj->show(boot_kobj->data, boot_attr->type, str);
+	return ret;
+}
+
+static const struct sysfs_ops iscsi_boot_attr_ops = {
+	.show = iscsi_boot_show_attribute,
+};
+
+static void iscsi_boot_kobj_release(struct kobject *kobj)
+{
+	struct iscsi_boot_kobj *boot_kobj =
+			container_of(kobj, struct iscsi_boot_kobj, kobj);
+
+	kfree(boot_kobj->data);
+	kfree(boot_kobj);
+}
+
+static struct kobj_type iscsi_boot_ktype = {
+	.release = iscsi_boot_kobj_release,
+	.sysfs_ops = &iscsi_boot_attr_ops,
+};
+
+#define iscsi_boot_rd_attr(fnname, sysfs_name, attr_type)		\
+static struct iscsi_boot_attr iscsi_boot_attr_##fnname = {	\
+	.attr	= { .name = __stringify(sysfs_name), .mode = 0444 },	\
+	.type	= attr_type,						\
+}
+
+/* Target attrs */
+iscsi_boot_rd_attr(tgt_index, index, ISCSI_BOOT_TGT_INDEX);
+iscsi_boot_rd_attr(tgt_flags, flags, ISCSI_BOOT_TGT_FLAGS);
+iscsi_boot_rd_attr(tgt_ip, ip-addr, ISCSI_BOOT_TGT_IP_ADDR);
+iscsi_boot_rd_attr(tgt_port, port, ISCSI_BOOT_TGT_PORT);
+iscsi_boot_rd_attr(tgt_lun, lun, ISCSI_BOOT_TGT_LUN);
+iscsi_boot_rd_attr(tgt_chap, chap-type, ISCSI_BOOT_TGT_CHAP_TYPE);
+iscsi_boot_rd_attr(tgt_nic, nic-assoc, ISCSI_BOOT_TGT_NIC_ASSOC);
+iscsi_boot_rd_attr(tgt_name, target-name, ISCSI_BOOT_TGT_NAME);
+iscsi_boot_rd_attr(tgt_chap_name, chap-name, ISCSI_BOOT_TGT_CHAP_NAME);
+iscsi_boot_rd_attr(tgt_chap_secret, chap-secret, ISCSI_BOOT_TGT_CHAP_SECRET);
+iscsi_boot_rd_attr(tgt_chap_rev_name, rev-chap-name,
+		   ISCSI_BOOT_TGT_REV_CHAP_NAME);
+iscsi_boot_rd_attr(tgt_chap_rev_secret, rev-chap-name-secret,
+		   ISCSI_BOOT_TGT_REV_CHAP_SECRET);
+
+static struct attribute *target_attrs[] = {
+	&iscsi_boot_attr_tgt_index.attr,
+	&iscsi_boot_attr_tgt_flags.attr,
+	&iscsi_boot_attr_tgt_ip.attr,
+	&iscsi_boot_attr_tgt_port.attr,
+	&iscsi_boot_attr_tgt_lun.attr,
+	&iscsi_boot_attr_tgt_chap.attr,
+	&iscsi_boot_attr_tgt_nic.attr,
+	&iscsi_boot_attr_tgt_name.attr,
+	&iscsi_boot_attr_tgt_chap_name.attr,
+	&iscsi_boot_attr_tgt_chap_secret.attr,
+	&iscsi_boot_attr_tgt_chap_rev_name.attr,
+	&iscsi_boot_attr_tgt_chap_rev_secret.attr,
+	NULL
+};
+
+static mode_t iscsi_boot_tgt_attr_is_visible(struct kobject *kobj,
+					     struct attribute *attr, int i)
+{
+	struct iscsi_boot_kobj *boot_kobj =
+			container_of(kobj, struct iscsi_boot_kobj, kobj);
+
+	if (attr ==  &iscsi_boot_attr_tgt_index.attr)
+		return boot_kobj->is_visible(boot_kobj->data,
+					     ISCSI_BOOT_TGT_INDEX);
+	else if (attr == &iscsi_boot_attr_tgt_flags.attr)
+		return boot_kobj->is_visible(boot_kobj->data,
+					     ISCSI_BOOT_TGT_FLAGS);
+	else if (attr == &iscsi_boot_attr_tgt_ip.attr)
+		return boot_kobj->is_visible(boot_kobj->data,
+					      ISCSI_BOOT_TGT_IP_ADDR);
+	else if (attr == &iscsi_boot_attr_tgt_port.attr)
+		return boot_kobj->is_visible(boot_kobj->data,
+					      ISCSI_BOOT_TGT_PORT);
+	else if (attr == &iscsi_boot_attr_tgt_lun.attr)
+		return boot_kobj->is_visible(boot_kobj->data,
+					      ISCSI_BOOT_TGT_LUN);
+	else if (attr == &iscsi_boot_attr_tgt_chap.attr)
+		return boot_kobj->is_visible(boot_kobj->data,
+					     ISCSI_BOOT_TGT_CHAP_TYPE);
+	else if (attr == &iscsi_boot_attr_tgt_nic.attr)
+		return boot_kobj->is_visible(boot_kobj->data,
+					     ISCSI_BOOT_TGT_NIC_ASSOC);
+	else if (attr == &iscsi_boot_attr_tgt_name.attr)
+		return boot_kobj->is_visible(boot_kobj->data,
+					     ISCSI_BOOT_TGT_NAME);
+	else if (attr == &iscsi_boot_attr_tgt_chap_name.attr)
+		return boot_kobj->is_visible(boot_kobj->data,
+					     ISCSI_BOOT_TGT_CHAP_NAME);
+	else if (attr == &iscsi_boot_attr_tgt_chap_secret.attr)
+		return boot_kobj->is_visible(boot_kobj->data,
+					     ISCSI_BOOT_TGT_CHAP_SECRET);
+	else if (attr == &iscsi_boot_attr_tgt_chap_rev_name.attr)
+		return boot_kobj->is_visible(boot_kobj->data,
+					     ISCSI_BOOT_TGT_REV_CHAP_NAME);
+	else if (attr == &iscsi_boot_attr_tgt_chap_rev_secret.attr)
+		return boot_kobj->is_visible(boot_kobj->data,
+					     ISCSI_BOOT_TGT_REV_CHAP_SECRET);
+	return 0;
+}
+
+static struct attribute_group iscsi_boot_target_attr_group = {
+	.attrs = target_attrs,
+	.is_visible = iscsi_boot_tgt_attr_is_visible,
+};
+
+/* Ethernet attrs */
+iscsi_boot_rd_attr(eth_index, index, ISCSI_BOOT_ETH_INDEX);
+iscsi_boot_rd_attr(eth_flags, flags, ISCSI_BOOT_ETH_FLAGS);
+iscsi_boot_rd_attr(eth_ip, ip-addr, ISCSI_BOOT_ETH_IP_ADDR);
+iscsi_boot_rd_attr(eth_subnet, subnet-mask, ISCSI_BOOT_ETH_SUBNET_MASK);
+iscsi_boot_rd_attr(eth_origin, origin, ISCSI_BOOT_ETH_ORIGIN);
+iscsi_boot_rd_attr(eth_gateway, gateway, ISCSI_BOOT_ETH_GATEWAY);
+iscsi_boot_rd_attr(eth_primary_dns, primary-dns, ISCSI_BOOT_ETH_PRIMARY_DNS);
+iscsi_boot_rd_attr(eth_secondary_dns, secondary-dns,
+		   ISCSI_BOOT_ETH_SECONDARY_DNS);
+iscsi_boot_rd_attr(eth_dhcp, dhcp, ISCSI_BOOT_ETH_DHCP);
+iscsi_boot_rd_attr(eth_vlan, vlan, ISCSI_BOOT_ETH_VLAN);
+iscsi_boot_rd_attr(eth_mac, mac, ISCSI_BOOT_ETH_MAC);
+iscsi_boot_rd_attr(eth_hostname, hostname, ISCSI_BOOT_ETH_HOSTNAME);
+
+static struct attribute *ethernet_attrs[] = {
+	&iscsi_boot_attr_eth_index.attr,
+	&iscsi_boot_attr_eth_flags.attr,
+	&iscsi_boot_attr_eth_ip.attr,
+	&iscsi_boot_attr_eth_subnet.attr,
+	&iscsi_boot_attr_eth_origin.attr,
+	&iscsi_boot_attr_eth_gateway.attr,
+	&iscsi_boot_attr_eth_primary_dns.attr,
+	&iscsi_boot_attr_eth_secondary_dns.attr,
+	&iscsi_boot_attr_eth_dhcp.attr,
+	&iscsi_boot_attr_eth_vlan.attr,
+	&iscsi_boot_attr_eth_mac.attr,
+	&iscsi_boot_attr_eth_hostname.attr,
+	NULL
+};
+
+static mode_t iscsi_boot_eth_attr_is_visible(struct kobject *kobj,
+					     struct attribute *attr, int i)
+{
+	struct iscsi_boot_kobj *boot_kobj =
+			container_of(kobj, struct iscsi_boot_kobj, kobj);
+
+	if (attr ==  &iscsi_boot_attr_eth_index.attr)
+		return boot_kobj->is_visible(boot_kobj->data,
+					     ISCSI_BOOT_ETH_INDEX);
+	else if (attr ==  &iscsi_boot_attr_eth_flags.attr)
+		return boot_kobj->is_visible(boot_kobj->data,
+					     ISCSI_BOOT_ETH_FLAGS);
+	else if (attr ==  &iscsi_boot_attr_eth_ip.attr)
+		return boot_kobj->is_visible(boot_kobj->data,
+					     ISCSI_BOOT_ETH_IP_ADDR);
+	else if (attr ==  &iscsi_boot_attr_eth_subnet.attr)
+		return boot_kobj->is_visible(boot_kobj->data,
+					     ISCSI_BOOT_ETH_SUBNET_MASK);
+	else if (attr ==  &iscsi_boot_attr_eth_origin.attr)
+		return boot_kobj->is_visible(boot_kobj->data,
+					     ISCSI_BOOT_ETH_ORIGIN);
+	else if (attr ==  &iscsi_boot_attr_eth_gateway.attr)
+		return boot_kobj->is_visible(boot_kobj->data,
+					     ISCSI_BOOT_ETH_GATEWAY);
+	else if (attr ==  &iscsi_boot_attr_eth_primary_dns.attr)
+		return boot_kobj->is_visible(boot_kobj->data,
+					     ISCSI_BOOT_ETH_PRIMARY_DNS);
+	else if (attr ==  &iscsi_boot_attr_eth_secondary_dns.attr)
+		return boot_kobj->is_visible(boot_kobj->data,
+					     ISCSI_BOOT_ETH_SECONDARY_DNS);
+	else if (attr ==  &iscsi_boot_attr_eth_dhcp.attr)
+		return boot_kobj->is_visible(boot_kobj->data,
+					     ISCSI_BOOT_ETH_DHCP);
+	else if (attr ==  &iscsi_boot_attr_eth_vlan.attr)
+		return boot_kobj->is_visible(boot_kobj->data,
+					     ISCSI_BOOT_ETH_VLAN);
+	else if (attr ==  &iscsi_boot_attr_eth_mac.attr)
+		return boot_kobj->is_visible(boot_kobj->data,
+					     ISCSI_BOOT_ETH_MAC);
+	else if (attr ==  &iscsi_boot_attr_eth_hostname.attr)
+		return boot_kobj->is_visible(boot_kobj->data,
+					     ISCSI_BOOT_ETH_HOSTNAME);
+	return 0;
+}
+
+static struct attribute_group iscsi_boot_ethernet_attr_group = {
+	.attrs = ethernet_attrs,
+	.is_visible = iscsi_boot_eth_attr_is_visible,
+};
+
+/* Initiator attrs */
+iscsi_boot_rd_attr(ini_index, index, ISCSI_BOOT_INI_INDEX);
+iscsi_boot_rd_attr(ini_flags, flags, ISCSI_BOOT_INI_FLAGS);
+iscsi_boot_rd_attr(ini_isns, isns-server, ISCSI_BOOT_INI_ISNS_SERVER);
+iscsi_boot_rd_attr(ini_slp, slp-server, ISCSI_BOOT_INI_SLP_SERVER);
+iscsi_boot_rd_attr(ini_primary_radius, pri-radius-server,
+		   ISCSI_BOOT_INI_PRI_RADIUS_SERVER);
+iscsi_boot_rd_attr(ini_secondary_radius, sec-radius-server,
+		   ISCSI_BOOT_INI_SEC_RADIUS_SERVER);
+iscsi_boot_rd_attr(ini_name, initiator-name, ISCSI_BOOT_INI_INITIATOR_NAME);
+
+static struct attribute *initiator_attrs[] = {
+	&iscsi_boot_attr_ini_index.attr,
+	&iscsi_boot_attr_ini_flags.attr,
+	&iscsi_boot_attr_ini_isns.attr,
+	&iscsi_boot_attr_ini_slp.attr,
+	&iscsi_boot_attr_ini_primary_radius.attr,
+	&iscsi_boot_attr_ini_secondary_radius.attr,
+	&iscsi_boot_attr_ini_name.attr,
+	NULL
+};
+
+static mode_t iscsi_boot_ini_attr_is_visible(struct kobject *kobj,
+					     struct attribute *attr, int i)
+{
+	struct iscsi_boot_kobj *boot_kobj =
+			container_of(kobj, struct iscsi_boot_kobj, kobj);
+
+	if (attr ==  &iscsi_boot_attr_ini_index.attr)
+		return boot_kobj->is_visible(boot_kobj->data,
+					     ISCSI_BOOT_INI_INDEX);
+	if (attr ==  &iscsi_boot_attr_ini_flags.attr)
+		return boot_kobj->is_visible(boot_kobj->data,
+					     ISCSI_BOOT_INI_FLAGS);
+	if (attr ==  &iscsi_boot_attr_ini_isns.attr)
+		return boot_kobj->is_visible(boot_kobj->data,
+					     ISCSI_BOOT_INI_ISNS_SERVER);
+	if (attr ==  &iscsi_boot_attr_ini_slp.attr)
+		return boot_kobj->is_visible(boot_kobj->data,
+					     ISCSI_BOOT_INI_SLP_SERVER);
+	if (attr ==  &iscsi_boot_attr_ini_primary_radius.attr)
+		return boot_kobj->is_visible(boot_kobj->data,
+					     ISCSI_BOOT_INI_PRI_RADIUS_SERVER);
+	if (attr ==  &iscsi_boot_attr_ini_secondary_radius.attr)
+		return boot_kobj->is_visible(boot_kobj->data,
+					     ISCSI_BOOT_INI_SEC_RADIUS_SERVER);
+	if (attr ==  &iscsi_boot_attr_ini_name.attr)
+		return boot_kobj->is_visible(boot_kobj->data,
+					     ISCSI_BOOT_INI_INITIATOR_NAME);
+
+	return 0;
+}
+
+static struct attribute_group iscsi_boot_initiator_attr_group = {
+	.attrs = initiator_attrs,
+	.is_visible = iscsi_boot_ini_attr_is_visible,
+};
+
+static struct iscsi_boot_kobj *
+iscsi_boot_create_kobj(struct iscsi_boot_kset *boot_kset,
+		       struct attribute_group *attr_group,
+		       const char *name, int index, void *data,
+		       ssize_t (*show) (void *data, int type, char *buf),
+		       mode_t (*is_visible) (void *data, int type))
+{
+	struct iscsi_boot_kobj *boot_kobj;
+
+	boot_kobj = kzalloc(sizeof(*boot_kobj), GFP_KERNEL);
+	if (!boot_kobj)
+		return NULL;
+	INIT_LIST_HEAD(&boot_kobj->list);
+
+	boot_kobj->kobj.kset = boot_kset->kset;
+	if (kobject_init_and_add(&boot_kobj->kobj, &iscsi_boot_ktype,
+				 NULL, name, index)) {
+		kfree(boot_kobj);
+		return NULL;
+	}
+	boot_kobj->data = data;
+	boot_kobj->show = show;
+	boot_kobj->is_visible = is_visible;
+
+	if (sysfs_create_group(&boot_kobj->kobj, attr_group)) {
+		/*
+		 * We do not want to free this because the caller
+		 * will assume that since the creation call failed
+		 * the boot kobj was not setup and the normal release
+		 * path is not being run.
+		 */
+		boot_kobj->data = NULL;
+		kobject_put(&boot_kobj->kobj);
+		return NULL;
+	}
+	boot_kobj->attr_group = attr_group;
+
+	kobject_uevent(&boot_kobj->kobj, KOBJ_ADD);
+	/* Nothing broke so lets add it to the list. */
+	list_add_tail(&boot_kobj->list, &boot_kset->kobj_list);
+	return boot_kobj;
+}
+
+static void iscsi_boot_remove_kobj(struct iscsi_boot_kobj *boot_kobj)
+{
+	list_del(&boot_kobj->list);
+	sysfs_remove_group(&boot_kobj->kobj, boot_kobj->attr_group);
+	kobject_put(&boot_kobj->kobj);
+}
+
+/**
+ * iscsi_boot_create_target() - create boot target sysfs dir
+ * @boot_kset: boot kset
+ * @index: the target id
+ * @data: driver specific data for target
+ * @show: attr show function
+ * @is_visible: attr visibility function
+ *
+ * Note: The boot sysfs lib will free the data passed in for the caller
+ * when all refs to the target kobject have been released.
+ */
+struct iscsi_boot_kobj *
+iscsi_boot_create_target(struct iscsi_boot_kset *boot_kset, int index,
+			 void *data,
+			 ssize_t (*show) (void *data, int type, char *buf),
+			 mode_t (*is_visible) (void *data, int type))
+{
+	return iscsi_boot_create_kobj(boot_kset, &iscsi_boot_target_attr_group,
+				      "target%d", index, data, show, is_visible);
+}
+EXPORT_SYMBOL_GPL(iscsi_boot_create_target);
+
+/**
+ * iscsi_boot_create_initiator() - create boot initiator sysfs dir
+ * @boot_kset: boot kset
+ * @index: the initiator id
+ * @data: driver specific data
+ * @show: attr show function
+ * @is_visible: attr visibility function
+ *
+ * Note: The boot sysfs lib will free the data passed in for the caller
+ * when all refs to the initiator kobject have been released.
+ */
+struct iscsi_boot_kobj *
+iscsi_boot_create_initiator(struct iscsi_boot_kset *boot_kset, int index,
+			    void *data,
+			    ssize_t (*show) (void *data, int type, char *buf),
+			    mode_t (*is_visible) (void *data, int type))
+{
+	return iscsi_boot_create_kobj(boot_kset,
+				      &iscsi_boot_initiator_attr_group,
+				      "initiator", index, data, show,
+				      is_visible);
+}
+EXPORT_SYMBOL_GPL(iscsi_boot_create_initiator);
+
+/**
+ * iscsi_boot_create_ethernet() - create boot ethernet sysfs dir
+ * @boot_kset: boot kset
+ * @index: the ethernet device id
+ * @data: driver specific data
+ * @show: attr show function
+ * @is_visible: attr visibility function
+ *
+ * Note: The boot sysfs lib will free the data passed in for the caller
+ * when all refs to the ethernet kobject have been released.
+ */
+struct iscsi_boot_kobj *
+iscsi_boot_create_ethernet(struct iscsi_boot_kset *boot_kset, int index,
+			   void *data,
+			   ssize_t (*show) (void *data, int type, char *buf),
+			   mode_t (*is_visible) (void *data, int type))
+{
+	return iscsi_boot_create_kobj(boot_kset,
+				      &iscsi_boot_ethernet_attr_group,
+				      "ethernet%d", index, data, show,
+				      is_visible);
+}
+EXPORT_SYMBOL_GPL(iscsi_boot_create_ethernet);
+
+/**
+ * iscsi_boot_create_kset() - creates root sysfs tree
+ * @set_name: name of root dir
+ */
+struct iscsi_boot_kset *iscsi_boot_create_kset(const char *set_name)
+{
+	struct iscsi_boot_kset *boot_kset;
+
+	boot_kset = kzalloc(sizeof(*boot_kset), GFP_KERNEL);
+	if (!boot_kset)
+		return NULL;
+
+	boot_kset->kset = kset_create_and_add(set_name, NULL, firmware_kobj);
+	if (!boot_kset->kset) {
+		kfree(boot_kset);
+		return NULL;
+	}
+
+	INIT_LIST_HEAD(&boot_kset->kobj_list);
+	return boot_kset;
+}
+EXPORT_SYMBOL_GPL(iscsi_boot_create_kset);
+
+/**
+ * iscsi_boot_create_host_kset() - creates root sysfs tree for a scsi host
+ * @hostno: host number of scsi host
+ */
+struct iscsi_boot_kset *iscsi_boot_create_host_kset(unsigned int hostno)
+{
+	struct iscsi_boot_kset *boot_kset;
+	char *set_name;
+
+	set_name = kasprintf(GFP_KERNEL, "iscsi_boot%u", hostno);
+	if (!set_name)
+		return NULL;
+
+	boot_kset = iscsi_boot_create_kset(set_name);
+	kfree(set_name);
+	return boot_kset;
+}
+EXPORT_SYMBOL_GPL(iscsi_boot_create_host_kset);
+
+/**
+ * iscsi_boot_destroy_kset() - destroy kset and kobjects under it
+ * @boot_kset: boot kset
+ *
+ * This will remove the kset and kobjects and attrs under it.
+ */
+void iscsi_boot_destroy_kset(struct iscsi_boot_kset *boot_kset)
+{
+	struct iscsi_boot_kobj *boot_kobj, *tmp_kobj;
+
+	list_for_each_entry_safe(boot_kobj, tmp_kobj,
+				 &boot_kset->kobj_list, list)
+		iscsi_boot_remove_kobj(boot_kobj);
+
+	kset_unregister(boot_kset->kset);
+}
+EXPORT_SYMBOL_GPL(iscsi_boot_destroy_kset);