4 files changed, 317 insertions, 0 deletions

diff --git a/drivers/scsi/Kconfig b/drivers/scsi/Kconfig
index 96df148ed969..68adc3cc8ad2 100644
--- a/drivers/scsi/Kconfig
+++ b/drivers/scsi/Kconfig
@@ -1,5 +1,11 @@
 menu "SCSI device support"
 
+config RAID_ATTRS
+        tristate "RAID Transport Class"
+        default n
+        ---help---
+          Provides RAID
+
 config SCSI
         tristate "SCSI device support"
         ---help---
diff --git a/drivers/scsi/Makefile b/drivers/scsi/Makefile
index 3746fb9fa2f5..85f9e6bb34b9 100644
--- a/drivers/scsi/Makefile
+++ b/drivers/scsi/Makefile
@@ -22,6 +22,8 @@ subdir-$(CONFIG_PCMCIA)		+= pcmcia
 
 obj-$(CONFIG_SCSI)              += scsi_mod.o
 
+obj-$(CONFIG_RAID_ATTRS)        += raid_class.o
+
 # --- NOTE ORDERING HERE ---
 # For kernel non-modular link, transport attributes need to
 # be initialised before drivers
diff --git a/drivers/scsi/raid_class.c b/drivers/scsi/raid_class.c
new file mode 100644
index 000000000000..f1ea5027865f
--- /dev/null
+++ b/drivers/scsi/raid_class.c
@@ -0,0 +1,250 @@
+/*
+ * RAID Attributes
+ */
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/list.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 class_device_attribute private_attrs[RAID_NUM_ATTRS];
+        /* The array of null terminated pointers to attributes 
+         * needed by scsi_sysfs.c */
+        struct class_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 class_device_to_raid_internal(cdev) ({                          \
+        struct attribute_container *ac =                                \
+                attribute_container_classdev_to_container(cdev);        \
+        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 (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 class_device *cdev)
+{
+        struct raid_data *rd;
+
+        BUG_ON(class_get_devdata(cdev));
+
+        rd = kmalloc(sizeof(*rd), GFP_KERNEL);
+        if (!rd)
+                return -ENOMEM;
+
+        memset(rd, 0, sizeof(*rd));
+        INIT_LIST_HEAD(&rd->component_list);
+        class_set_devdata(cdev, rd);
+                
+        return 0;
+}
+
+static int raid_remove(struct transport_container *tc, struct device *dev,
+                       struct class_device *cdev)
+{
+        struct raid_data *rd = class_get_devdata(cdev);
+        struct raid_component *rc, *next;
+        class_set_devdata(cdev, NULL);
+        list_for_each_entry_safe(rc, next, &rd->component_list, node) {
+                char buf[40];
+                snprintf(buf, sizeof(buf), "component-%d", rc->num);
+                list_del(&rc->node);
+                sysfs_remove_link(&cdev->kobj, buf);
+                kfree(rc);
+        }
+        kfree(class_get_devdata(cdev));
+        return 0;
+}
+
+static DECLARE_TRANSPORT_CLASS(raid_class,
+                               "raid_devices",
+                               raid_setup,
+                               raid_remove,
+                               NULL);
+
+static struct {
+        enum raid_state value;
+        char            *name;
+} raid_states[] = {
+        { RAID_ACTIVE, "active" },
+        { RAID_DEGRADED, "degraded" },
+        { RAID_RESYNCING, "resyncing" },
+        { RAID_OFFLINE, "offline" },
+};
+
+static const char *raid_state_name(enum raid_state state)
+{
+        int i;
+        char *name = NULL;
+
+        for (i = 0; i < sizeof(raid_states)/sizeof(raid_states[0]); i++) {
+                if (raid_states[i].value == state) {
+                        name = raid_states[i].name;
+                        break;
+                }
+        }
+        return name;
+}
+
+
+#define raid_attr_show_internal(attr, fmt, var, code)                   \
+static ssize_t raid_show_##attr(struct class_device *cdev, char *buf)   \
+{                                                                       \
+        struct raid_data *rd = class_get_devdata(cdev);                 \
+        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 CLASS_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 CLASS_DEVICE_ATTR(attr, S_IRUGO, raid_show_##attr, NULL)
+
+#define ATTR_CODE(attr)                                                 \
+        struct raid_internal *i = class_device_to_raid_internal(cdev);  \
+        if (i->f->get_##attr)                                           \
+                i->f->get_##attr(cdev->dev);
+
+#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, ATTR_CODE(attr))
+
+raid_attr_ro(level);
+raid_attr_ro_fn(resync);
+raid_attr_ro_state(state);
+
+void raid_component_add(struct raid_template *r,struct device *raid_dev,
+                        struct device *component_dev)
+{
+        struct class_device *cdev =
+                attribute_container_find_class_device(&r->raid_attrs.ac,
+                                                      raid_dev);
+        struct raid_component *rc;
+        struct raid_data *rd = class_get_devdata(cdev);
+        char buf[40];
+
+        rc = kmalloc(sizeof(*rc), GFP_KERNEL);
+        if (!rc)
+                return;
+
+        INIT_LIST_HEAD(&rc->node);
+        rc->dev = component_dev;
+        rc->num = rd->component_count++;
+
+        snprintf(buf, sizeof(buf), "component-%d", rc->num);
+        list_add_tail(&rc->node, &rd->component_list);
+        sysfs_create_link(&cdev->kobj, &component_dev->kobj, buf);
+}
+EXPORT_SYMBOL(raid_component_add);
+
+struct raid_template *
+raid_class_attach(struct raid_function_template *ft)
+{
+        struct raid_internal *i = kmalloc(sizeof(struct raid_internal),
+                                          GFP_KERNEL);
+        int count = 0;
+
+        if (unlikely(!i))
+                return NULL;
+
+        memset(i, 0, sizeof(*i));
+
+        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++] = &class_device_attr_level;
+        i->attrs[count++] = &class_device_attr_resync;
+        i->attrs[count++] = &class_device_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);
+
+        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);
+
diff --git a/include/linux/raid_class.h b/include/linux/raid_class.h
new file mode 100644
index 000000000000..a71123c28272
--- /dev/null
+++ b/include/linux/raid_class.h
@@ -0,0 +1,59 @@
+/*
+ */
+#include <linux/transport_class.h>
+
+struct raid_template {
+        struct transport_container raid_attrs;
+};
+
+struct raid_function_template {
+        void *cookie;
+        int (*is_raid)(struct device *);
+        void (*get_resync)(struct device *);
+        void (*get_state)(struct device *);
+};
+
+enum raid_state {
+        RAID_ACTIVE = 1,
+        RAID_DEGRADED,
+        RAID_RESYNCING,
+        RAID_OFFLINE,
+};
+
+struct raid_data {
+        struct list_head component_list;
+        int component_count;
+        int level;
+        enum raid_state state;
+        int resync;
+};
+
+#define DEFINE_RAID_ATTRIBUTE(type, attr)                                     \
+static inline void                                                            \
+raid_set_##attr(struct raid_template *r, struct device *dev, type value) {    \
+        struct class_device *cdev =                                           \
+                attribute_container_find_class_device(&r->raid_attrs.ac, dev);\
+        struct raid_data *rd;                                                 \
+        BUG_ON(!cdev);                                                        \
+        rd = class_get_devdata(cdev);                                         \
+        rd->attr = value;                                                     \
+}                                                                             \
+static inline type                                                            \
+raid_get_##attr(struct raid_template *r, struct device *dev) {                \
+        struct class_device *cdev =                                           \
+                attribute_container_find_class_device(&r->raid_attrs.ac, dev);\
+        struct raid_data *rd;                                                 \
+        BUG_ON(!cdev);                                                        \
+        rd = class_get_devdata(cdev);                                         \
+        return rd->attr;                                                      \
+}
+
+DEFINE_RAID_ATTRIBUTE(int, level)
+DEFINE_RAID_ATTRIBUTE(int, resync)
+DEFINE_RAID_ATTRIBUTE(enum raid_state, state)
+        
+struct raid_template *raid_class_attach(struct raid_function_template *);
+void raid_class_release(struct raid_template *);
+
+void raid_component_add(struct raid_template *, struct device *,
+                        struct device *);