rbd: separating mapping info from rbd_device

index cf5d109..8189841 100644
@@ -169,14 +169,15 @@ struct rbd_mapping {
 	u64                     features;
 	bool                    snap_exists;
 	bool			read_only;
+
+	int			dev_id;		/* blkdev unique id */
+	struct list_head	id_list;
 };
 
 /*
  * a single device
  */
 struct rbd_device {
-	int			dev_id;		/* blkdev unique id */
-
 	int			major;		/* blkdev assigned major */
 	struct gendisk		*disk;		/* blkdev's gendisk and rq */
 

@@ -205,8 +206,6 @@ struct rbd_device {
 
 	struct rbd_mapping	mapping;
 
-	struct list_head	node;
-
 	/* list of snapshots */
 	struct list_head	snaps;
 

@@ -666,6 +665,7 @@ static int rbd_dev_set_mapping(struct rbd_device *rbd_dev, char *snap_name)
 {
 	int ret;
 
+	INIT_LIST_HEAD(&rbd_dev->mapping.id_list);
 	if (!memcmp(snap_name, RBD_SNAP_HEAD_NAME,
 		    sizeof (RBD_SNAP_HEAD_NAME))) {
 		rbd_dev->mapping.snap_id = CEPH_NOSNAP;

@@ -1771,7 +1771,7 @@ static int rbd_init_disk(struct rbd_device *rbd_dev)
 		return -ENOMEM;
 
 	snprintf(disk->disk_name, sizeof(disk->disk_name), RBD_DRV_NAME "%d",
-		 rbd_dev->dev_id);
+		 rbd_dev->mapping.dev_id);
 	disk->major = rbd_dev->major;
 	disk->first_minor = 0;
 	disk->fops = &rbd_bd_ops;

@@ -2560,7 +2560,7 @@ static int rbd_bus_add_dev(struct rbd_device *rbd_dev)
 	dev->type = &rbd_device_type;
 	dev->parent = &rbd_root_dev;
 	dev->release = rbd_dev_release;
-	dev_set_name(dev, "%d", rbd_dev->dev_id);
+	dev_set_name(dev, "%d", rbd_dev->mapping.dev_id);
 	ret = device_register(dev);
 
 	mutex_unlock(&ctl_mutex);

@@ -2595,33 +2595,33 @@ static atomic64_t rbd_dev_id_max = ATOMIC64_INIT(0);
  * Get a unique rbd identifier for the given new rbd_dev, and add
  * the rbd_dev to the global list.  The minimum rbd id is 1.
  */
-static void rbd_dev_id_get(struct rbd_device *rbd_dev)
+static void rbd_dev_id_get(struct rbd_mapping *mapping)
 {
-	rbd_dev->dev_id = atomic64_inc_return(&rbd_dev_id_max);
+	mapping->dev_id = atomic64_inc_return(&rbd_dev_id_max);
 
 	spin_lock(&rbd_dev_list_lock);
-	list_add_tail(&rbd_dev->node, &rbd_dev_list);
+	list_add_tail(&mapping->id_list, &rbd_dev_list);
 	spin_unlock(&rbd_dev_list_lock);
-	dout("rbd_dev %p given dev id %llu\n", rbd_dev,
-		(unsigned long long) rbd_dev->dev_id);
+	dout("mapping %p given dev id %llu\n", mapping,
+		(unsigned long long) mapping->dev_id);
 }
 
 /*
  * Remove an rbd_dev from the global list, and record that its
  * identifier is no longer in use.
  */
-static void rbd_dev_id_put(struct rbd_device *rbd_dev)
+static void rbd_dev_id_put(struct rbd_mapping *mapping)
 {
 	struct list_head *tmp;
-	int rbd_id = rbd_dev->dev_id;
+	int rbd_id = mapping->dev_id;
 	int max_id;
 
 	rbd_assert(rbd_id > 0);
 
-	dout("rbd_dev %p released dev id %llu\n", rbd_dev,
-		(unsigned long long) rbd_dev->dev_id);
+	dout("mapping %p released dev id %llu\n", mapping,
+		(unsigned long long) mapping->dev_id);
 	spin_lock(&rbd_dev_list_lock);
-	list_del_init(&rbd_dev->node);
+	list_del_init(&mapping->id_list);
 
 	/*
 	 * If the id being "put" is not the current maximum, there

@@ -2639,11 +2639,11 @@ static void rbd_dev_id_put(struct rbd_device *rbd_dev)
 	 */
 	max_id = 0;
 	list_for_each_prev(tmp, &rbd_dev_list) {
-		struct rbd_device *rbd_dev;
+		struct rbd_mapping *rbd_map;
 
-		rbd_dev = list_entry(tmp, struct rbd_device, node);
-		if (rbd_dev->dev_id > max_id)
-			max_id = rbd_dev->dev_id;
+		rbd_map = list_entry(tmp, struct rbd_mapping, id_list);
+		if (rbd_map->dev_id > max_id)
+			max_id = rbd_map->dev_id;
 	}
 	spin_unlock(&rbd_dev_list_lock);
 

@@ -3035,7 +3035,6 @@ static ssize_t rbd_add(struct bus_type *bus,
 
 	/* static rbd_device initialization */
 	spin_lock_init(&rbd_dev->lock);
-	INIT_LIST_HEAD(&rbd_dev->node);
 	INIT_LIST_HEAD(&rbd_dev->snaps);
 	init_rwsem(&rbd_dev->header_rwsem);
 

@@ -3072,12 +3071,12 @@ static ssize_t rbd_add(struct bus_type *bus,
 		goto err_out_header;
 
 	/* generate unique id: find highest unique id, add one */
-	rbd_dev_id_get(rbd_dev);
+	rbd_dev_id_get(&rbd_dev->mapping);
 
 	/* Fill in the device name, now that we have its id. */
 	BUILD_BUG_ON(DEV_NAME_LEN
 			< sizeof (RBD_DRV_NAME) + MAX_INT_FORMAT_WIDTH);
-	sprintf(rbd_dev->name, "%s%d", RBD_DRV_NAME, rbd_dev->dev_id);
+	sprintf(rbd_dev->name, "%s%d", RBD_DRV_NAME, rbd_dev->mapping.dev_id);
 
 	/* Get our block major device number. */
 

@@ -3132,7 +3131,7 @@ err_out_disk:
 err_out_blkdev:
 	unregister_blkdev(rbd_dev->major, rbd_dev->name);
 err_out_id:
-	rbd_dev_id_put(rbd_dev);
+	rbd_dev_id_put(&rbd_dev->mapping);
 err_out_header:
 	rbd_header_free(&rbd_dev->header);
 err_out_client:

@@ -3156,17 +3155,20 @@ err_out_mem:
 static struct rbd_device *__rbd_get_dev(unsigned long dev_id)
 {
 	struct list_head *tmp;
-	struct rbd_device *rbd_dev;
 
 	spin_lock(&rbd_dev_list_lock);
 	list_for_each(tmp, &rbd_dev_list) {
-		rbd_dev = list_entry(tmp, struct rbd_device, node);
-		if (rbd_dev->dev_id == dev_id) {
-			spin_unlock(&rbd_dev_list_lock);
-			return rbd_dev;
-		}
+		struct rbd_mapping *mapping;
+
+		mapping = list_entry(tmp, struct rbd_mapping, id_list);
+		if (mapping->dev_id != dev_id)
+			continue;
+		spin_unlock(&rbd_dev_list_lock);
+
+		return container_of(mapping, struct rbd_device, mapping);
 	}
 	spin_unlock(&rbd_dev_list_lock);
+
 	return NULL;
 }
 

@@ -3198,7 +3200,7 @@ static void rbd_dev_release(struct device *dev)
 	kfree(rbd_dev->header_name);
 	kfree(rbd_dev->pool_name);
 	kfree(rbd_dev->image_name);
-	rbd_dev_id_put(rbd_dev);
+	rbd_dev_id_put(&rbd_dev->mapping);
 	kfree(rbd_dev);
 
 	/* release module ref */

index 8189841..250446d 100644
@@ -172,23 +172,22 @@ struct rbd_mapping {
 
 	int			dev_id;		/* blkdev unique id */
 	struct list_head	id_list;
+	char			name[DEV_NAME_LEN]; /* blkdev name, e.g. rbd3 */
+
+	int			major;		/* blkdev assigned major */
+	spinlock_t		lock;		/* queue lock */
+	struct gendisk		*disk;		/* blkdev's gendisk and rq */
+
+	struct rbd_options	rbd_opts;
 };
 
 /*
  * a single device
  */
 struct rbd_device {
-	int			major;		/* blkdev assigned major */
-	struct gendisk		*disk;		/* blkdev's gendisk and rq */
-
 	u32			image_format;	/* Either 1 or 2 */
-	struct rbd_options	rbd_opts;
 	struct rbd_client	*rbd_client;
 
-	char			name[DEV_NAME_LEN]; /* blkdev name, e.g. rbd3 */
-
-	spinlock_t		lock;		/* queue lock */
-
 	struct rbd_image_header	header;
 	char			*image_id;
 	size_t			image_id_len;

@@ -452,7 +451,7 @@ static int parse_rbd_opts_token(char *c, void *private)
 static int rbd_get_client(struct rbd_device *rbd_dev, const char