[SCSI] libfcoe: add implementation to support fcoe transport

Add the new fcoe_transport.c file that implements basic fcoe transport
interface. Eventually, the sysfs entries to create/destroy/enable/disable
an FCoE instance will be coming to the fcoe transport layer, who does a
look-up to find the corresponding transport provide and pass the corresponding
action over to the identified provider.

The fcoe.ko will become the default fcoe transport provider that can support
FCoE on any given netdev interfaces, as the Open-FCoE.org's default software
FCoE HBA solution. Any vendor specific FCoE HBA driver that is built on top
of Open-FCoE's kernel stack of libfc & libfcoe as well as the user land tool
of fcoe-utils can easily plug-in and start running FCoE on their network
interfaces. The fcoe.ko will be converted to act as the default provider if
no vendor specific transport provider is found, as it is always added to the
very end of the list of attached transports.
Signed-off-by: Yi Zou <yi.zou@intel.com>
Signed-off-by: Bhanu Prakash Gollapudi <bprakash@broadcom.com>
Signed-off-by: Robert Love <robert.w.love@intel.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

drivers/scsi/fcoe/fcoe_transport.c

+/*
+ * Copyright(c) 2008 - 2011 Intel Corporation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Maintained at www.Open-FCoE.org
+ */
+
+#include <linux/types.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/netdevice.h>
+#include <linux/errno.h>
+#include <scsi/libfcoe.h>
+
+#include "libfcoe.h"
+
+static int fcoe_transport_create(const char *, struct kernel_param *);
+static int fcoe_transport_destroy(const char *, struct kernel_param *);
+static int fcoe_transport_show(char *buffer, const struct kernel_param *kp);
+static struct fcoe_transport *fcoe_transport_lookup(struct net_device *device);
+static struct fcoe_transport *fcoe_netdev_map_lookup(struct net_device *device);
+static int fcoe_transport_enable(const char *, struct kernel_param *);
+static int fcoe_transport_disable(const char *, struct kernel_param *);
+
+static LIST_HEAD(fcoe_transports);
+static LIST_HEAD(fcoe_netdevs);
+static DEFINE_MUTEX(ft_mutex);
+
+module_param_call(show, NULL, fcoe_transport_show, NULL, S_IRUSR);
+__MODULE_PARM_TYPE(show, "string");
+MODULE_PARM_DESC(show, " Show attached FCoE transports");
+
+module_param_call(create, fcoe_transport_create, NULL,
+		  (void *)FIP_MODE_FABRIC, S_IWUSR);
+__MODULE_PARM_TYPE(create, "string");
+MODULE_PARM_DESC(create, " Creates fcoe instance on a ethernet interface");
+
+module_param_call(create_vn2vn, fcoe_transport_create, NULL,
+		  (void *)FIP_MODE_VN2VN, S_IWUSR);
+__MODULE_PARM_TYPE(create_vn2vn, "string");
+MODULE_PARM_DESC(create_vn2vn, " Creates a VN_node to VN_node FCoE instance "
+		 "on an Ethernet interface");
+
+module_param_call(destroy, fcoe_transport_destroy, NULL, NULL, S_IWUSR);
+__MODULE_PARM_TYPE(destroy, "string");
+MODULE_PARM_DESC(destroy, " Destroys fcoe instance on a ethernet interface");
+
+module_param_call(enable, fcoe_transport_enable, NULL, NULL, S_IWUSR);
+__MODULE_PARM_TYPE(enable, "string");
+MODULE_PARM_DESC(enable, " Enables fcoe on a ethernet interface.");
+
+module_param_call(disable, fcoe_transport_disable, NULL, NULL, S_IWUSR);
+__MODULE_PARM_TYPE(disable, "string");
+MODULE_PARM_DESC(disable, " Disables fcoe on a ethernet interface.");
+
+/**
+ * fcoe_transport_lookup - find an fcoe transport that matches a netdev
+ * @netdev: The netdev to look for from all attached transports
+ *
+ * Returns : ptr to the fcoe transport that supports this netdev or NULL
+ * if not found.
+ *
+ * The ft_mutex should be held when this is called
+ */
+static struct fcoe_transport *fcoe_transport_lookup(struct net_device *netdev)
+{
+	struct fcoe_transport *ft = NULL;
+
+	list_for_each_entry(ft, &fcoe_transports, list)
+		if (ft->match && ft->match(netdev))
+			return ft;
+	return NULL;
+}
+
+/**
+ * fcoe_transport_attach - Attaches an FCoE transport
+ * @ft: The fcoe transport to be attached
+ *
+ * Returns : 0 for success
+ */
+int fcoe_transport_attach(struct fcoe_transport *ft)
+{
+	int rc = 0;
+
+	mutex_lock(&ft_mutex);
+	if (ft->attached) {
+		LIBFCOE_TRANSPORT_DBG("transport %s already attached\n",
+				       ft->name);
+		rc = -EEXIST;
+		goto out_attach;
+	}
+
+	/* Add default transport to the tail */
+	if (strcmp(ft->name, FCOE_TRANSPORT_DEFAULT))
+		list_add(&ft->list, &fcoe_transports);
+	else
+		list_add_tail(&ft->list, &fcoe_transports);
+
+	ft->attached = true;
+	LIBFCOE_TRANSPORT_DBG("attaching transport %s\n", ft->name);
+
+out_attach:
+	mutex_unlock(&ft_mutex);
+	return rc;
+}
+EXPORT_SYMBOL(fcoe_transport_attach);
+
+/**
+ * fcoe_transport_attach - Detaches an FCoE transport
+ * @ft: The fcoe transport to be attached
+ *
+ * Returns : 0 for success
+ */
+int fcoe_transport_detach(struct fcoe_transport *ft)
+{
+	int rc = 0;
+
+	mutex_lock(&ft_mutex);
+	if (!ft->attached) {
+		LIBFCOE_TRANSPORT_DBG("transport %s already detached\n",
+			ft->name);
+		rc = -ENODEV;
+		goto out_attach;
+	}
+
+	list_del(&ft->list);
+	ft->attached = false;
+	LIBFCOE_TRANSPORT_DBG("detaching transport %s\n", ft->name);
+
+out_attach:
+	mutex_unlock(&ft_mutex);
+	return rc;
+
+}
+EXPORT_SYMBOL(fcoe_transport_detach);
+
+static int fcoe_transport_show(char *buffer, const struct kernel_param *kp)
+{
+	int i, j;
+	struct fcoe_transport *ft = NULL;
+
+	i = j = sprintf(buffer, "Attached FCoE transports:");
+	mutex_lock(&ft_mutex);
+	list_for_each_entry(ft, &fcoe_transports, list) {
+		i += snprintf(&buffer[i], IFNAMSIZ, "%s ", ft->name);
+		if (i >= PAGE_SIZE)
+			break;
+	}
+	mutex_unlock(&ft_mutex);
+	if (i == j)
+		i += snprintf(&buffer[i], IFNAMSIZ, "none");
+	return i;
+}
+
+static int __init fcoe_transport_init(void)
+{
+	return 0;
+}
+
+static int __exit fcoe_transport_exit(void)
+{
+	struct fcoe_transport *ft;
+
+	mutex_lock(&ft_mutex);
+	list_for_each_entry(ft, &fcoe_transports, list)
+		printk(KERN_ERR "FCoE transport %s is still attached!\n",
+		      ft->name);
+	mutex_unlock(&ft_mutex);
+	return 0;
+}
+
+
+static int fcoe_add_netdev_mapping(struct net_device *netdev,
+					struct fcoe_transport *ft)
+{
+	struct fcoe_netdev_mapping *nm;
+
+	nm = kmalloc(sizeof(*nm), GFP_KERNEL);
+	if (!nm) {
+		printk(KERN_ERR "Unable to allocate netdev_mapping");
+		return -ENOMEM;
+	}
+
+	nm->netdev = netdev;
+	nm->ft = ft;
+
+	list_add(&nm->list, &fcoe_netdevs);
+	return 0;
+}
+
+
+static void fcoe_del_netdev_mapping(struct net_device *netdev)
+{
+	struct fcoe_netdev_mapping *nm = NULL, *tmp;
+
+	list_for_each_entry_safe(nm, tmp, &fcoe_netdevs, list) {
+		if (nm->netdev == netdev) {
+			list_del(&nm->list);
+			kfree(nm);
+			return;
+		}
+	}
+}
+
+
+/**
+ * fcoe_netdev_map_lookup - find the fcoe transport that matches the netdev on which
+ * it was created
+ *
+ * Returns : ptr to the fcoe transport that supports this netdev or NULL
+ * if not found.
+ *
+ * The ft_mutex should be held when this is called
+ */
+static struct fcoe_transport *fcoe_netdev_map_lookup(struct net_device *netdev)
+{
+	struct fcoe_transport *ft = NULL;
+	struct fcoe_netdev_mapping *nm;
+
+	list_for_each_entry(nm, &fcoe_netdevs, list) {
+		if (netdev == nm->netdev) {
+			ft = nm->ft;
+			return ft;
+		}
+	}
+
+	return NULL;
+}
+
+/**
+ * fcoe_if_to_netdev() - Parse a name buffer to get a net device
+ * @buffer: The name of the net device
+ *
+ * Returns: NULL or a ptr to net_device
+ */
+static struct net_device *fcoe_if_to_netdev(const char *buffer)
+{
+	char *cp;
+	char ifname[IFNAMSIZ + 2];
+
+	if (buffer) {
+		strlcpy(ifname, buffer, IFNAMSIZ);
+		cp = ifname + strlen(ifname);
+		while (--cp >= ifname && *cp == '\n')
+			*cp = '\0';
+		return dev_get_by_name(&init_net, ifname);
+	}
+	return NULL;
+}
+
+/**
+ * fcoe_transport_create() - Create a fcoe interface
+ * @buffer: The name of the Ethernet interface to create on
+ * @kp:	    The associated kernel param
+ *
+ * Called from sysfs. This holds the ft_mutex while calling the
+ * registered fcoe transport's create function.
+ *
+ * Returns: 0 for success
+ */
+static int fcoe_transport_create(const char *buffer, struct kernel_param *kp)
+{
+	int rc = -ENODEV;
+	struct net_device *netdev = NULL;
+	struct fcoe_transport *ft = NULL;
+	enum fip_state fip_mode = (enum fip_state)(long)kp->arg;
+
+	if (!mutex_trylock(&ft_mutex))
+		return restart_syscall();
+
+#ifdef CONFIG_LIBFCOE_MODULE
+	/*
+	 * Make sure the module has been initialized, and is not about to be
+	 * removed.  Module parameter sysfs files are writable before the
+	 * module_init function is called and after module_exit.
+	 */
+	if (THIS_MODULE->state != MODULE_STATE_LIVE)
+		goto out_nodev;
+#endif
+
+	netdev = fcoe_if_to_netdev(buffer);
+	if (!netdev) {
+		LIBFCOE_TRANSPORT_DBG("Invalid device %s.\n", buffer);
+		goto out_nodev;
+	}
+
+	ft = fcoe_netdev_map_lookup(netdev);
+	if (ft) {
+		LIBFCOE_TRANSPORT_DBG("transport %s already has existing "
+				      "FCoE instance on %s.\n",
+				      ft->name, netdev->name);
+		rc = -EEXIST;
+		goto out_putdev;
+	}
+
+	ft = fcoe_transport_lookup(netdev);
+	if (!ft) {
+		LIBFCOE_TRANSPORT_DBG("no FCoE transport found for %s.\n",
+				      netdev->name);
+		goto out_putdev;
+	}
+
+	rc = fcoe_add_netdev_mapping(netdev, ft);
+	if (rc) {
+		LIBFCOE_TRANSPORT_DBG("failed to add new netdev mapping "
+				      "for FCoE transport %s for %s.\n",
+				      ft->name, netdev->name);
+		goto out_putdev;
+	}
+
+	/* pass to transport create */
+	rc = ft->create ? ft->create(netdev, fip_mode) : -ENODEV;
+	if (rc)
+		fcoe_del_netdev_mapping(netdev);
+
+	LIBFCOE_TRANSPORT_DBG("transport %s %s to create fcoe on %s.\n",
+			      ft->name, (rc) ? "failed" : "succeeded",
+			      netdev->name);
+
+out_putdev:
+	dev_put(netdev);
+out_nodev:
+	mutex_unlock(&ft_mutex);
+	if (rc == -ERESTARTSYS)
+		return restart_syscall();
+	else
+		return rc;
+}
+
+/**
+ * fcoe_transport_destroy() - Destroy a FCoE interface
+ * @buffer: The name of the Ethernet interface to be destroyed
+ * @kp:	    The associated kernel parameter
+ *
+ * Called from sysfs. This holds the ft_mutex while calling the
+ * registered fcoe transport's destroy function.
+ *
+ * Returns: 0 for success
+ */
+static int fcoe_transport_destroy(const char *buffer, struct kernel_param *kp)
+{
+	int rc = -ENODEV;
+	struct net_device *netdev = NULL;
+	struct fcoe_transport *ft = NULL;
+
+	if (!mutex_trylock(&ft_mutex))
+		return restart_syscall();
+
+#ifdef CONFIG_LIBFCOE_MODULE
+	/*
+	 * Make sure the module has been initialized, and is not about to be
+	 * removed.  Module parameter sysfs files are writable before the
+	 * module_init function is called and after module_exit.
+	 */
+	if (THIS_MODULE->state != MODULE_STATE_LIVE)
+		goto out_nodev;
+#endif
+
+	netdev = fcoe_if_to_netdev(buffer);
+	if (!netdev) {
+		LIBFCOE_TRANSPORT_DBG("invalid device %s.\n", buffer);
+		goto out_nodev;
+	}
+
+	ft = fcoe_netdev_map_lookup(netdev);
+	if (!ft) {
+		LIBFCOE_TRANSPORT_DBG("no FCoE transport found for %s.\n",
+				      netdev->name);
+		goto out_putdev;
+	}
+
+	/* pass to transport destroy */
+	rc = ft->destroy ? ft->destroy(netdev) : -ENODEV;
+	fcoe_del_netdev_mapping(netdev);
+	LIBFCOE_TRANSPORT_DBG("transport %s %s to destroy fcoe on %s.\n",
+			      ft->name, (rc) ? "failed" : "succeeded",
+			      netdev->name);
+
+out_putdev:
+	dev_put(netdev);
+out_nodev:
+	mutex_unlock(&ft_mutex);
+
+	if (rc == -ERESTARTSYS)
+		return restart_syscall();
+	else
+		return rc;
+}
+
+/**
+ * fcoe_transport_disable() - Disables a FCoE interface
+ * @buffer: The name of the Ethernet interface to be disabled
+ * @kp:	    The associated kernel parameter
+ *
+ * Called from sysfs.
+ *
+ * Returns: 0 for success
+ */
+static int fcoe_transport_disable(const char *buffer, struct kernel_param *kp)
+{
+	int rc = -ENODEV;
+	struct net_device *netdev = NULL;
+	struct fcoe_transport *ft = NULL;
+
+	if (!mutex_trylock(&ft_mutex))
+		return restart_syscall();
+
+#ifdef CONFIG_LIBFCOE_MODULE
+	/*
+	 * Make sure the module has been initialized, and is not about to be
+	 * removed.  Module parameter sysfs files are writable before the
+	 * module_init function is called and after module_exit.
+	 */
+	if (THIS_MODULE->state != MODULE_STATE_LIVE)
+		goto out_nodev;
+#endif
+
+	netdev = fcoe_if_to_netdev(buffer);
+	if (!netdev)
+		goto out_nodev;
+
+	ft = fcoe_netdev_map_lookup(netdev);
+	if (!ft)
+		goto out_putdev;
+
+	rc = ft->disable ? ft->disable(netdev) : -ENODEV;
+
+out_putdev:
+	dev_put(netdev);
+out_nodev:
+	mutex_unlock(&ft_mutex);
+
+	if (rc == -ERESTARTSYS)
+		return restart_syscall();
+	else
+		return rc;
+}
+
+/**
+ * fcoe_transport_enable() - Enables a FCoE interface
+ * @buffer: The name of the Ethernet interface to be enabled
+ * @kp:     The associated kernel parameter
+ *
+ * Called from sysfs.
+ *
+ * Returns: 0 for success
+ */
+static int fcoe_transport_enable(const char *buffer, struct kernel_param *kp)
+{
+	int rc = -ENODEV;
+	struct net_device *netdev = NULL;
+	struct fcoe_transport *ft = NULL;
+
+	if (!mutex_trylock(&ft_mutex))
+		return restart_syscall();
+
+#ifdef CONFIG_LIBFCOE_MODULE
+	/*
+	 * Make sure the module has been initialized, and is not about to be
+	 * removed.  Module parameter sysfs files are writable before the
+	 * module_init function is called and after module_exit.
+	 */
+	if (THIS_MODULE->state != MODULE_STATE_LIVE)
+		goto out_nodev;
+#endif
+
+	netdev = fcoe_if_to_netdev(buffer);
+	if (!netdev)
+		goto out_nodev;
+
+	ft = fcoe_netdev_map_lookup(netdev);
+	if (!ft)
+		goto out_putdev;
+
+	rc = ft->enable ? ft->enable(netdev) : -ENODEV;
+
+out_putdev:
+	dev_put(netdev);
+out_nodev:
+	mutex_unlock(&ft_mutex);
+	if (rc == -ERESTARTSYS)
+		return restart_syscall();
+	else
+		return rc;
+}
+
+/**
+ * libfcoe_init() - Initialization routine for libfcoe.ko
+ */
+static int __init libfcoe_init(void)
+{
+	fcoe_transport_init();
+
+	return 0;
+}
+module_init(libfcoe_init);
+
+/**
+ * libfcoe_exit() - Tear down libfcoe.ko
+ */
+static void __exit libfcoe_exit(void)
+{
+	fcoe_transport_exit();
+}
+module_exit(libfcoe_exit);

drivers/scsi/fcoe/libfcoe.h

@@ -4,6 +4,7 @@
 extern unsigned int libfcoe_debug_logging;
 #define LIBFCOE_LOGGING	    0x01 /* General logging, not categorized */
 #define LIBFCOE_FIP_LOGGING 0x02 /* FIP logging */
+#define LIBFCOE_TRANSPORT_LOGGING	0x04 /* FCoE transport logging */
 
 #define LIBFCOE_CHECK_LOGGING(LEVEL, CMD)		\
 do {							\
@@ -22,4 +23,9 @@ do {							\
 			      printk(KERN_INFO "host%d: fip: " fmt,	\
 				     (fip)->lp->host->host_no, ##args);)
 
+#define LIBFCOE_TRANSPORT_DBG(fmt, args...)				\
+	LIBFCOE_CHECK_LOGGING(LIBFCOE_TRANSPORT_LOGGING,		\
+			      printk(KERN_INFO "%s: " fmt,		\
+				     __func__, ##args);)
+
 #endif /* _FCOE_LIBFCOE_H_ */