1 files changed, 268 insertions, 0 deletions
diff --git a/drivers/scsi/raid_class.c b/drivers/scsi/raid_class.c
new file mode 100644
index 000000000..95a86e0df
--- /dev/null
+++ b/drivers/scsi/raid_class.c
@@ -0,0 +1,268 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * raid_class.c - implementation of a simple raid visualisation class
+ *
+ * Copyright (c) 2005 - James Bottomley <James.Bottomley@steeleye.com>
+ *
+ * This class is designed to allow raid attributes to be visualised and
+ * manipulated in a form independent of the underlying raid.  Ultimately this
+ * should work for both hardware and software raids.
+ */
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/list.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/raid_class.h>
+#include <scsi/scsi_device.h>
+#include <scsi/scsi_host.h>
+
+#define RAID_NUM_ATTRS	3
+
+struct raid_internal {
+	struct raid_template r;
+	struct raid_function_template *f;
+	/* The actual attributes */
+	struct device_attribute private_attrs[RAID_NUM_ATTRS];
+	/* The array of null terminated pointers to attributes 
+	 * needed by scsi_sysfs.c */
+	struct device_attribute *attrs[RAID_NUM_ATTRS + 1];
+};
+
+struct raid_component {
+	struct list_head node;
+	struct device dev;
+	int num;
+};
+
+#define to_raid_internal(tmpl)	container_of(tmpl, struct raid_internal, r)
+
+#define tc_to_raid_internal(tcont) ({					\
+	struct raid_template *r =					\
+		container_of(tcont, struct raid_template, raid_attrs);	\
+	to_raid_internal(r);						\
+})
+
+#define ac_to_raid_internal(acont) ({					\
+	struct transport_container *tc =				\
+		container_of(acont, struct transport_container, ac);	\
+	tc_to_raid_internal(tc);					\
+})
+
+#define device_to_raid_internal(dev) ({				\
+	struct attribute_container *ac =				\
+		attribute_container_classdev_to_container(dev);	\
+	ac_to_raid_internal(ac);					\
+})
+	
+
+static int raid_match(struct attribute_container *cont, struct device *dev)
+{
+	/* We have to look for every subsystem that could house
+	 * emulated RAID devices, so start with SCSI */
+	struct raid_internal *i = ac_to_raid_internal(cont);
+
+	if (IS_ENABLED(CONFIG_SCSI) && scsi_is_sdev_device(dev)) {
+		struct scsi_device *sdev = to_scsi_device(dev);
+
+		if (i->f->cookie != sdev->host->hostt)
+			return 0;
+
+		return i->f->is_raid(dev);
+	}
+	/* FIXME: look at other subsystems too */
+	return 0;
+}
+
+static int raid_setup(struct transport_container *tc, struct device *dev,
+		       struct device *cdev)
+{
+	struct raid_data *rd;
+
+	BUG_ON(dev_get_drvdata(cdev));
+
+	rd = kzalloc(sizeof(*rd), GFP_KERNEL);
+	if (!rd)
+		return -ENOMEM;
+
+	INIT_LIST_HEAD(&rd->component_list);
+	dev_set_drvdata(cdev, rd);
+		
+	return 0;
+}
+
+static int raid_remove(struct transport_container *tc, struct device *dev,
+		       struct device *cdev)
+{
+	struct raid_data *rd = dev_get_drvdata(cdev);
+	struct raid_component *rc, *next;
+	dev_printk(KERN_ERR, dev, "RAID REMOVE\n");
+	dev_set_drvdata(cdev, NULL);
+	list_for_each_entry_safe(rc, next, &rd->component_list, node) {
+		list_del(&rc->node);
+		dev_printk(KERN_ERR, rc->dev.parent, "RAID COMPONENT REMOVE\n");
+		device_unregister(&rc->dev);
+	}
+	dev_printk(KERN_ERR, dev, "RAID REMOVE DONE\n");
+	kfree(rd);
+	return 0;
+}
+
+static DECLARE_TRANSPORT_CLASS(raid_class,
+			       "raid_devices",
+			       raid_setup,
+			       raid_remove,
+			       NULL);
+
+static const struct {
+	enum raid_state	value;
+	char		*name;
+} raid_states[] = {
+	{ RAID_STATE_UNKNOWN, "unknown" },
+	{ RAID_STATE_ACTIVE, "active" },
+	{ RAID_STATE_DEGRADED, "degraded" },
+	{ RAID_STATE_RESYNCING, "resyncing" },
+	{ RAID_STATE_OFFLINE, "offline" },
+};
+
+static const char *raid_state_name(enum raid_state state)
+{
+	int i;
+	char *name = NULL;
+
+	for (i = 0; i < ARRAY_SIZE(raid_states); i++) {
+		if (raid_states[i].value == state) {
+			name = raid_states[i].name;
+			break;
+		}
+	}
+	return name;
+}
+
+static struct {
+	enum raid_level value;
+	char *name;
+} raid_levels[] = {
+	{ RAID_LEVEL_UNKNOWN, "unknown" },
+	{ RAID_LEVEL_LINEAR, "linear" },
+	{ RAID_LEVEL_0, "raid0" },
+	{ RAID_LEVEL_1, "raid1" },
+	{ RAID_LEVEL_10, "raid10" },
+	{ RAID_LEVEL_1E, "raid1e" },
+	{ RAID_LEVEL_3, "raid3" },
+	{ RAID_LEVEL_4, "raid4" },
+	{ RAID_LEVEL_5, "raid5" },
+	{ RAID_LEVEL_50, "raid50" },
+	{ RAID_LEVEL_6, "raid6" },
+	{ RAID_LEVEL_JBOD, "jbod" },
+};
+
+static const char *raid_level_name(enum raid_level level)
+{
+	int i;
+	char *name = NULL;
+
+	for (i = 0; i < ARRAY_SIZE(raid_levels); i++) {
+		if (raid_levels[i].value == level) {
+			name = raid_levels[i].name;
+			break;
+		}
+	}
+	return name;
+}
+
+#define raid_attr_show_internal(attr, fmt, var, code)			\
+static ssize_t raid_show_##attr(struct device *dev, 			\
+				struct device_attribute *attr, 		\
+				char *buf)				\
+{									\
+	struct raid_data *rd = dev_get_drvdata(dev);			\
+	code								\
+	return snprintf(buf, 20, #fmt "\n", var);			\
+}
+
+#define raid_attr_ro_states(attr, states, code)				\
+raid_attr_show_internal(attr, %s, name,					\
+	const char *name;						\
+	code								\
+	name = raid_##states##_name(rd->attr);				\
+)									\
+static DEVICE_ATTR(attr, S_IRUGO, raid_show_##attr, NULL)
+
+
+#define raid_attr_ro_internal(attr, code)				\
+raid_attr_show_internal(attr, %d, rd->attr, code)			\
+static DEVICE_ATTR(attr, S_IRUGO, raid_show_##attr, NULL)
+
+#define ATTR_CODE(attr)							\
+	struct raid_internal *i = device_to_raid_internal(dev);		\
+	if (i->f->get_##attr)						\
+		i->f->get_##attr(dev->parent);
+
+#define raid_attr_ro(attr)	raid_attr_ro_internal(attr, )
+#define raid_attr_ro_fn(attr)	raid_attr_ro_internal(attr, ATTR_CODE(attr))
+#define raid_attr_ro_state(attr)	raid_attr_ro_states(attr, attr, )
+#define raid_attr_ro_state_fn(attr)	raid_attr_ro_states(attr, attr, ATTR_CODE(attr))
+
+
+raid_attr_ro_state(level);
+raid_attr_ro_fn(resync);
+raid_attr_ro_state_fn(state);
+
+struct raid_template *
+raid_class_attach(struct raid_function_template *ft)
+{
+	struct raid_internal *i = kzalloc(sizeof(struct raid_internal),
+					  GFP_KERNEL);
+	int count = 0;
+
+	if (unlikely(!i))
+		return NULL;
+
+	i->f = ft;
+
+	i->r.raid_attrs.ac.class = &raid_class.class;
+	i->r.raid_attrs.ac.match = raid_match;
+	i->r.raid_attrs.ac.attrs = &i->attrs[0];
+
+	attribute_container_register(&i->r.raid_attrs.ac);
+
+	i->attrs[count++] = &dev_attr_level;
+	i->attrs[count++] = &dev_attr_resync;
+	i->attrs[count++] = &dev_attr_state;
+
+	i->attrs[count] = NULL;
+	BUG_ON(count > RAID_NUM_ATTRS);
+
+	return &i->r;
+}
+EXPORT_SYMBOL(raid_class_attach);
+
+void
+raid_class_release(struct raid_template *r)
+{
+	struct raid_internal *i = to_raid_internal(r);
+
+	BUG_ON(attribute_container_unregister(&i->r.raid_attrs.ac));
+
+	kfree(i);
+}
+EXPORT_SYMBOL(raid_class_release);
+
+static __init int raid_init(void)
+{
+	return transport_class_register(&raid_class);
+}
+
+static __exit void raid_exit(void)
+{
+	transport_class_unregister(&raid_class);
+}
+
+MODULE_AUTHOR("James Bottomley");
+MODULE_DESCRIPTION("RAID device class");
+MODULE_LICENSE("GPL");
+
+module_init(raid_init);
+module_exit(raid_exit);
+