[PATCH] preparation to use of driverfs refcounts, part 1 - partitions

	* update_partition() split into add_partition() and delete_partition().
	* all updating of ->part[] is switched to these two (including initial
filling/final cleaning).
	* per-partition devices are allocated on-demand and never reused.
We allocate struct device in add_partition() and put reference to it into
hd_struct.  ->release() for that struct device frees it.  delete_partition()
removes reference from hd_struct and does put_device() on it.  Basically,
we get rid of problems with reused struct device by never reusing them...
	At that point devices for partitions are nice and sane.

drivers/block/ioctl.c

@@ -58,9 +58,7 @@ static int blkpg_ioctl(struct block_device *bdev, struct blkpg_ioctl_arg *arg)
 					return -EBUSY;
 			}
 			/* all seems OK */
-			disk->part[part - 1].start_sect = start;
-			disk->part[part - 1].nr_sects = length;
-			update_partition(disk, part);
+			add_partition(disk, part, start, length);
 			return 0;
 		case BLKPG_DEL_PARTITION:
 			if (disk->part[part - 1].nr_sects == 0)
@@ -79,9 +77,7 @@ static int blkpg_ioctl(struct block_device *bdev, struct blkpg_ioctl_arg *arg)
 			fsync_bdev(bdevp);
 			invalidate_bdev(bdevp, 0);
 
-			disk->part[part].start_sect = 0;
-			disk->part[part].nr_sects = 0;
-			update_partition(disk, part);
+			delete_partition(disk, part);
 			bd_release(bdevp);
 			bdput(bdevp);
 			return 0;

include/linux/genhd.h

@@ -62,7 +62,7 @@ struct hd_struct {
 	sector_t start_sect;
 	sector_t nr_sects;
 	devfs_handle_t de;              /* primary (master) devfs entry  */
-	struct device hd_driverfs_dev;  /* support driverfs hiearchy     */
+	struct device *hd_driverfs_dev;  /* support driverfs hiearchy     */
 };
 
 #define GENHD_FL_REMOVABLE  1
@@ -262,7 +262,8 @@ struct unixware_disklabel {
 char *disk_name (struct gendisk *hd, int part, char *buf);
 
 extern int rescan_partitions(struct gendisk *disk, struct block_device *bdev);
-extern void update_partition(struct gendisk *disk, int part);
+extern void add_partition(struct gendisk *, int, sector_t, sector_t);
+extern void delete_partition(struct gendisk *, int);
 
 extern struct gendisk *alloc_disk(int minors);
 extern void put_disk(struct gendisk *disk);