Message-Id: <1252720601.2067.212.camel@haakon2.linux-iscsi.org>
Date:	Fri, 11 Sep 2009 18:56:41 -0700
From:	"Nicholas A. Bellinger" <nab@...ux-iscsi.org>
To:	LKML <linux-kernel@...r.kernel.org>,
	linux-scsi <linux-scsi@...r.kernel.org>
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	Greg KH <greg@...ah.com>,
	Douglas Gilbert <dgilbert@...erlog.com>,
	James Bottomley <James.Bottomley@...senPartnership.com>,
	Hannes Reinecke <hare@...e.de>,
	FUJITA Tomonori <fujita.tomonori@....ntt.co.jp>,
	Mike Christie <michaelc@...wisc.edu>,
	Joel Becker <joel.becker@...cle.com>,
	"Martin K. Petersen" <martin.petersen@...cle.com>,
	Christoph Hellwig <hch@....de>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Alan Stern <stern@...land.harvard.edu>,
	Boaz Harrosh <bharrosh@...asas.com>,
	Florian Haas <florian.haas@...bit.com>,
	Philipp Reisner <philipp.reisner@...bit.com>
Subject: [RFC PATCH 8/19] Target_Core_Mod Subsystem and SE Object plugin
	infrastructure

[RFC PATCH 8/19] Target_Core_Mod Subsystem and SE Object plugin infrastructure

This patch adds the simple plugin infrastructure used by subsystem and seobj plugins.

Signed-off-by: Nicholas A. Bellinger <nab@...ux-iscsi.org>
diff --git a/drivers/target/target_core_plugin.c b/drivers/target/target_core_plugin.c
new file mode 100644
index 0000000..9f7ea97
--- /dev/null
+++ b/drivers/target/target_core_plugin.c
@@ -0,0 +1,326 @@
+/*******************************************************************************
+ * Filename:  target_core_plugin.c
+ *
+ * Copyright (c) 2006-2007 SBE, Inc.  All Rights Reserved.
+ * Copyright (c) 2007-2009 Rising Tide Software, Inc.
+ * Copyright (c) 2008-2009 Linux-iSCSI.org
+ *
+ * Nicholas A. Bellinger <nab@...nel.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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.
+ *
+ * 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *
+ ******************************************************************************/
+
+#define TARGET_CORE_PLUGIN_C
+
+#include <linux/net.h>
+#include <linux/string.h>
+#include <linux/timer.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/smp_lock.h>
+#include <linux/in.h>
+#include <net/sock.h>
+#include <net/tcp.h>
+
+#include <target/target_core_base.h>
+#include <target/target_core_hba.h>
+#include <target/target_core_seobj.h>
+#include <target/target_core_transport.h>
+#include <target/target_core_plugin.h>
+
+#undef TARGET_CORE_PLUGIN_C
+
+void plugin_load_all_classes(void)
+{
+	/*
+	 * Setup Transport Plugins
+	 */
+	plugin_register_class(PLUGIN_TYPE_TRANSPORT, "TRANSPORT", MAX_PLUGINS);
+	transport_load_plugins();
+
+	/*
+	 * Setup Storage Engine Object Plugins
+	 */
+	plugin_register_class(PLUGIN_TYPE_OBJ, "OBJ", MAX_PLUGINS);
+	se_obj_load_plugins();
+}
+EXPORT_SYMBOL(plugin_load_all_classes);
+
+se_plugin_class_t *plugin_get_class(
+	u32 plugin_class_type)
+{
+	se_plugin_class_t *pc;
+
+	if (plugin_class_type > MAX_PLUGIN_CLASSES) {
+		printk(KERN_ERR "Passed plugin class type: %u exceeds"
+			" MAX_PLUGIN_CLASSES: %d\n", plugin_class_type,
+			MAX_PLUGIN_CLASSES);
+		return NULL;
+	}
+
+	pc = &se_global->plugin_class_list[plugin_class_type];
+	if (!pc->plugin_array)
+		return NULL;
+
+	return pc;
+}
+
+int plugin_register_class(
+	u32 plugin_class_type,
+	unsigned char *plugin_class_name,
+	int max_plugins)
+{
+	u32 i;
+	se_plugin_class_t *pc;
+	se_plugin_t *p;
+
+	if (strlen(plugin_class_name) > MAX_PLUGIN_CLASS_NAME) {
+		printk(KERN_ERR "plugin_class_name exceeds MAX_PLUGIN_CLASS"
+				"_NAME: %u\n", MAX_PLUGIN_CLASS_NAME);
+		return -1;
+	}
+	spin_lock(&se_global->plugin_class_lock);
+	if (plugin_class_type > MAX_PLUGIN_CLASSES) {
+		printk(KERN_ERR "Passed plugin class type: %u exceeds"
+			" MAX_PLUGIN_CLASSES: %d\n", plugin_class_type,
+			MAX_PLUGIN_CLASSES);
+		return -1;
+	}
+
+	pc = &se_global->plugin_class_list[plugin_class_type];
+	if (pc->plugin_array) {
+		printk(KERN_ERR "Plugin Class Type: %u already exists\n",
+			plugin_class_type);
+		return -1;
+	}
+	spin_unlock(&se_global->plugin_class_lock);
+
+	pc->plugin_array = kzalloc(sizeof(se_plugin_t) * max_plugins,
+				GFP_KERNEL);
+	if (!(pc->plugin_array)) {
+		printk(KERN_ERR "Unable to locate pc->plugin_array\n");
+		return -1;
+	}
+
+	spin_lock_init(&pc->plugin_lock);
+	pc->max_plugins = max_plugins;
+	pc->plugin_class = plugin_class_type;
+	snprintf(pc->plugin_class_name, MAX_PLUGIN_CLASS_NAME,
+		"%s", plugin_class_name);
+
+	for (i = 0; i < max_plugins; i++) {
+		p = &pc->plugin_array[i];
+		p->plugin_class = pc;
+	}
+
+	printk(KERN_INFO "SE_PC[%u] - Registered Plugin Class: %s\n",
+			pc->plugin_class, pc->plugin_class_name);
+
+	return 0;
+}
+EXPORT_SYMBOL(plugin_register_class);
+
+int plugin_deregister_class(u32 plugin_class_type)
+{
+	int i;
+	se_plugin_class_t *pc;
+	se_plugin_t *p;
+
+	pc = plugin_get_class(plugin_class_type);
+	if (!(pc))
+		return -1;
+
+	for (i = 0; i < MAX_PLUGINS; i++) {
+		p = &pc->plugin_array[i];
+
+		if (!p->plugin_obj)
+			continue;
+
+		plugin_deregister(i, plugin_class_type);
+	}
+
+	kfree(pc->plugin_array);
+	pc->plugin_array = NULL;
+
+	return 0;
+}
+EXPORT_SYMBOL(plugin_deregister_class);
+
+void plugin_unload_all_classes(void)
+{
+	u32 i;
+	se_plugin_class_t *pc;
+
+	for (i = 0; i < MAX_PLUGIN_CLASSES; i++) {
+		pc = &se_global->plugin_class_list[i];
+
+		if (!pc->plugin_array)
+			continue;
+
+		plugin_deregister_class(i);
+	}
+
+	return;
+}
+EXPORT_SYMBOL(plugin_unload_all_classes);
+
+void *plugin_get_obj(
+	u32 plugin_class,
+	u32 plugin_loc,
+	int *ret)
+{
+	se_plugin_class_t *pc;
+	se_plugin_t *p;
+
+	pc = plugin_get_class(plugin_class);
+	if (!(pc))
+		return NULL;
+
+	spin_lock(&pc->plugin_lock);
+	if (plugin_loc > pc->max_plugins) {
+		printk(KERN_ERR "Passed plugin_loc: %d exceeds"
+			" pc->max_plugins: %d\n", plugin_loc, pc->max_plugins);
+		goto out;
+	}
+
+	p = &pc->plugin_array[plugin_loc];
+	if (!p->plugin_obj) {
+		printk(KERN_ERR "Passed plugin_loc: %u does not exist!\n",
+				plugin_loc);
+		goto out;
+	}
+	spin_unlock(&pc->plugin_lock);
+
+	*ret = 0;
+	return p->plugin_obj;
+out:
+	*ret = -1;
+	spin_unlock(&pc->plugin_lock);
+	return NULL;
+}
+EXPORT_SYMBOL(plugin_get_obj);
+
+struct se_plugin_s *plugin_register(
+	void *obj,
+	u32 plugin_loc,
+	unsigned char *plugin_name,
+	u32 plugin_class,
+	void (*get_plugin_info)(void *, char *, int *),
+	int (*plugin_init)(void),
+	void (*plugin_free)(void),
+	int *ret)
+{
+	se_plugin_class_t *pc;
+	se_plugin_t *p;
+	int err;
+
+	if (!obj) {
+		printk(KERN_ERR "obj or plugin_class pointers are NULL!\n");
+		return NULL;
+	}
+
+	if (strlen(plugin_name) > MAX_PLUGIN_NAME) {
+		printk(KERN_ERR "plugin_name exceeds MAX_PLUGIN_NAME: %u\n",
+				MAX_PLUGIN_NAME);
+		return NULL;
+	}
+
+	pc = plugin_get_class(plugin_class);
+	if (!(pc))
+		return NULL;
+
+	spin_lock(&pc->plugin_lock);
+	if (plugin_loc > pc->max_plugins) {
+		printk(KERN_ERR "Passed plugin_loc: %u exceeds pc->max_plugins:"
+			" %d\n", plugin_loc, pc->max_plugins);
+		*ret = -1;
+		goto out;
+	}
+
+	p = &pc->plugin_array[plugin_loc];
+	if (p->plugin_obj) {
+		printk(KERN_ERR "Passed plugin_loc: %u already registered\n",
+			plugin_loc);
+		*ret = -1;
+		goto out;
+	}
+
+	p->plugin_obj = obj;
+	p->get_plugin_info = get_plugin_info;
+	p->plugin_free	= plugin_free;
+	p->plugin_state = PLUGIN_REGISTERED;
+	p->plugin_type = plugin_loc;
+	snprintf(p->plugin_name, MAX_PLUGIN_NAME, "%s", plugin_name);
+
+	printk(KERN_INFO "PLUGIN_%s[%u] - %s registered\n",
+			pc->plugin_class_name, plugin_loc, plugin_name);
+	spin_unlock(&pc->plugin_lock);
+
+	if (*plugin_init != NULL) {
+		err = (*plugin_init)();
+		if (err) {
+			plugin_deregister(plugin_loc, plugin_class);
+			return NULL;
+		}
+	}
+
+	return p;
+
+out:
+	spin_unlock(&pc->plugin_lock);
+	return NULL;
+}
+EXPORT_SYMBOL(plugin_register);
+
+int plugin_deregister(
+	u32 plugin_loc,
+	u32 plugin_class)
+{
+	int ret = 0;
+	se_plugin_class_t *pc;
+	se_plugin_t *p;
+
+	pc = plugin_get_class(plugin_class);
+	if (!(pc))
+		return -1;
+
+	spin_lock(&pc->plugin_lock);
+	if (plugin_loc > pc->max_plugins) {
+		printk(KERN_ERR "Passed plugin_loc: %u exceeds pc->max_plugins:"
+			" %d\n", plugin_loc, pc->max_plugins);
+		ret = -1;
+		goto out;
+	}
+
+	p = &pc->plugin_array[plugin_loc];
+	if (!p->plugin_obj) {
+		printk(KERN_ERR "Passed plugin_loc: %u not active!\n",
+			plugin_loc);
+		ret = -1;
+		goto out;
+	}
+	spin_unlock(&pc->plugin_lock);
+
+	if (p->plugin_free)
+		p->plugin_free();
+
+	spin_lock(&pc->plugin_lock);
+	p->plugin_obj = NULL;
+	p->plugin_state = PLUGIN_FREE;
+out:
+	spin_unlock(&pc->plugin_lock);
+	return ret;
+}
diff --git a/include/target/target_core_plugin.h b/include/target/target_core_plugin.h
new file mode 100644
index 0000000..bc3333b
--- /dev/null
+++ b/include/target/target_core_plugin.h
@@ -0,0 +1,73 @@
+/*******************************************************************************
+ * Filename:  target_core_plugin.h
+ *
+ * Copyright (c) 2006-2007 SBE, Inc.  All Rights Reserved.
+ * Copyright (c) 2007-2009 Rising Tide Software, Inc.
+ * Copyright (c) 2008-2009 Linux-iSCSI.org
+ *
+ * Nicholas A. Bellinger <nab@...nel.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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.
+ *
+ * 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *
+ ******************************************************************************/
+
+
+#ifndef TARGET_CORE_PLUGIN_H
+#define TARGET_CORE_PLUGIN_H
+
+#define PLUGIN_TYPE_TRANSPORT	0
+#define PLUGIN_TYPE_OBJ		1
+
+#define MAX_PLUGINS		32
+#define MAX_PLUGIN_CLASSES	16
+#define MAX_PLUGIN_CLASS_NAME	16
+#define MAX_PLUGIN_NAME		16
+
+#define PLUGIN_FREE		0
+#define PLUGIN_REGISTERED	1
+
+extern se_global_t *se_global;
+
+extern void plugin_load_all_classes(void);
+extern struct se_plugin_class_s *plugin_get_class(u32);
+extern int plugin_register_class(u32, unsigned char *, int);
+extern int plugin_deregister_class(u32);
+extern void plugin_unload_all_classes(void);
+extern void *plugin_get_obj(u32, u32, int *);
+extern struct se_plugin_s *plugin_register(void *, u32, unsigned char *, u32,
+				void (*get_plugin_info)(void *, char *, int *),
+				int (*plugin_init)(void),
+				void (*plugin_free)(void), int *);
+extern int plugin_deregister(u32, u32);
+
+typedef struct se_plugin_class_s {
+	unsigned char		plugin_class_name[MAX_PLUGIN_CLASS_NAME];
+	u32			plugin_class;
+	u32			max_plugins;
+	struct se_plugin_s	*plugin_array;
+	spinlock_t		plugin_lock;
+} se_plugin_class_t;
+
+typedef struct se_plugin_s	{
+	unsigned char		plugin_name[MAX_PLUGIN_NAME];
+	int			plugin_state;
+	u32			plugin_type;
+	se_plugin_class_t	*plugin_class;
+	void			*plugin_obj;
+	void (*get_plugin_info)(void *, char *, int *);
+	void (*plugin_free)(void);
+} se_plugin_t;
+
+#endif /* TARGET_CORE_PLUGIN_H */


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