return  kobj ? dev_to_disk(dev) : NULL;
 }
 
-/*
- * print a partitions - intended for places where the root filesystem can't be
- * mounted and thus to give the victim some idea of what went wrong
- */
-static int printk_partition(struct device *dev, void *data)
-{
-       struct gendisk *sgp;
-       char buf[BDEVNAME_SIZE];
-       int n;
-
-       if (dev->type != &disk_type)
-               return 0;
-
-       sgp = dev_to_disk(dev);
-       /*
-        * Don't show empty devices or things that have been surpressed
-        */
-       if (get_capacity(sgp) == 0 ||
-           (sgp->flags & GENHD_FL_SUPPRESS_PARTITION_INFO))
-               return 0;
-
-       /*
-        * Note, unlike /proc/partitions, I am showing the numbers in
-        * hex - the same format as the root= option takes.
-        */
-       printk("%02x%02x %10llu %s",
-               sgp->major, sgp->first_minor,
-               (unsigned long long)get_capacity(sgp) >> 1,
-               disk_name(sgp, 0, buf));
-       if (sgp->driverfs_dev != NULL &&
-           sgp->driverfs_dev->driver != NULL)
-               printk(" driver: %s\n",
-                       sgp->driverfs_dev->driver->name);
-       else
-               printk(" (driver?)\n");
-
-       /* now show the partitions */
-       for (n = 0; n < sgp->minors - 1; ++n) {
-               if (sgp->part[n] == NULL)
-                       continue;
-               if (sgp->part[n]->nr_sects == 0)
-                       continue;
-               printk("  %02x%02x %10llu %s\n",
-                       sgp->major, n + 1 + sgp->first_minor,
-                       (unsigned long long)sgp->part[n]->nr_sects >> 1,
-                       disk_name(sgp, n + 1, buf));
-       }
-
-       return 0;
-}
-
 /*
  * print a full list of all partitions - intended for places where the root
  * filesystem can't be mounted and thus to give the victim some idea of what
  */
 void __init printk_all_partitions(void)
 {
-       class_for_each_device(&block_class, NULL, NULL, printk_partition);
+       struct class_dev_iter iter;
+       struct device *dev;
+
+       class_dev_iter_init(&iter, &block_class, NULL, &disk_type);
+       while ((dev = class_dev_iter_next(&iter))) {
+               struct gendisk *disk = dev_to_disk(dev);
+               char buf[BDEVNAME_SIZE];
+               int n;
+
+               /*
+                * Don't show empty devices or things that have been
+                * surpressed
+                */
+               if (get_capacity(disk) == 0 ||
+                   (disk->flags & GENHD_FL_SUPPRESS_PARTITION_INFO))
+                       continue;
+
+               /*
+                * Note, unlike /proc/partitions, I am showing the
+                * numbers in hex - the same format as the root=
+                * option takes.
+                */
+               printk("%02x%02x %10llu %s",
+                      disk->major, disk->first_minor,
+                      (unsigned long long)get_capacity(disk) >> 1,
+                      disk_name(disk, 0, buf));
+               if (disk->driverfs_dev != NULL &&
+                   disk->driverfs_dev->driver != NULL)
+                       printk(" driver: %s\n",
+                              disk->driverfs_dev->driver->name);
+               else
+                       printk(" (driver?)\n");
+
+               /* now show the partitions */
+               for (n = 0; n < disk->minors - 1; ++n) {
+                       if (disk->part[n] == NULL)
+                               continue;
+                       if (disk->part[n]->nr_sects == 0)
+                               continue;
+                       printk("  %02x%02x %10llu %s\n",
+                              disk->major, n + 1 + disk->first_minor,
+                              (unsigned long long)disk->part[n]->nr_sects >> 1,
+                              disk_name(disk, n + 1, buf));
+               }
+       }
+       class_dev_iter_exit(&iter);
 }
 
 #ifdef CONFIG_PROC_FS
 /* iterator */
-static int find_start(struct device *dev, void *data)
+static void *disk_seqf_start(struct seq_file *seqf, loff_t *pos)
 {
-       loff_t *k = data;
+       loff_t skip = *pos;
+       struct class_dev_iter *iter;
+       struct device *dev;
 
-       if (dev->type != &disk_type)
-               return 0;
-       if (!*k)
-               return 1;
-       (*k)--;
-       return 0;
+       iter = kmalloc(GFP_KERNEL, sizeof(*iter));
+       if (!iter)
+               return ERR_PTR(-ENOMEM);
+
+       seqf->private = iter;
+       class_dev_iter_init(iter, &block_class, NULL, &disk_type);
+       do {
+               dev = class_dev_iter_next(iter);
+               if (!dev)
+                       return NULL;
+       } while (skip--);
+
+       return dev_to_disk(dev);
 }
 
-static void *part_start(struct seq_file *part, loff_t *pos)
+static void *disk_seqf_next(struct seq_file *seqf, void *v, loff_t *pos)
 {
        struct device *dev;
-       loff_t n = *pos;
-
-       if (!n)
-               part->private = (void *)1LU;    /* tell show to print header */
 
-       dev = class_find_device(&block_class, NULL, &n, find_start);
+       (*pos)++;
+       dev = class_dev_iter_next(seqf->private);
        if (dev)
                return dev_to_disk(dev);
 
        return NULL;
 }
 
-static int find_next(struct device *dev, void *data)
+static void disk_seqf_stop(struct seq_file *seqf, void *v)
 {
-       if (dev->type == &disk_type)
-               return 1;
-       return 0;
-}
+       struct class_dev_iter *iter = seqf->private;
 
-static void *part_next(struct seq_file *part, void *v, loff_t *pos)
-{
-       struct gendisk *gp = v;
-       struct device *dev;
-       ++*pos;
-       dev = class_find_device(&block_class, &gp->dev, NULL, find_next);
-       if (dev) {
-               put_device(dev);
-               return dev_to_disk(dev);
+       /* stop is called even after start failed :-( */
+       if (iter) {
+               class_dev_iter_exit(iter);
+               kfree(iter);
        }
-       return NULL;
 }
 
-static void part_stop(struct seq_file *part, void *v)
+static void *show_partition_start(struct seq_file *seqf, loff_t *pos)
 {
+       static void *p;
+
+       p = disk_seqf_start(seqf, pos);
+       if (!IS_ERR(p) && p)
+               seq_puts(seqf, "major minor  #blocks  name\n\n");
+       return p;
 }
 
 static int show_partition(struct seq_file *part, void *v)
 }
 
 const struct seq_operations partitions_op = {
-       .start  = part_start,
-       .next   = part_next,
-       .stop   = part_stop,
+       .start  = show_partition_start,
+       .next   = disk_seqf_next,
+       .stop   = disk_seqf_stop,
        .show   = show_partition
 };
 #endif
 };
 
 #ifdef CONFIG_PROC_FS
-/*
- * aggregate disk stat collector.  Uses the same stats that the sysfs
- * entries do, above, but makes them available through one seq_file.
- *
- * The output looks suspiciously like /proc/partitions with a bunch of
- * extra fields.
- */
-
-static void *diskstats_start(struct seq_file *part, loff_t *pos)
-{
-       struct device *dev;
-       loff_t n = *pos;
-
-       dev = class_find_device(&block_class, NULL, &n, find_start);
-       if (dev)
-               return dev_to_disk(dev);
-
-       return NULL;
-}
-
-static void *diskstats_next(struct seq_file *part, void *v, loff_t *pos)
-{
-       struct gendisk *gp = v;
-       struct device *dev;
-
-       ++*pos;
-       dev = class_find_device(&block_class, &gp->dev, NULL, find_next);
-       if (dev) {
-               put_device(dev);
-               return dev_to_disk(dev);
-       }
-       return NULL;
-}
-
-static void diskstats_stop(struct seq_file *part, void *v)
-{
-}
-
 static int diskstats_show(struct seq_file *s, void *v)
 {
        struct gendisk *gp = v;
 }
 
 const struct seq_operations diskstats_op = {
-       .start  = diskstats_start,
-       .next   = diskstats_next,
-       .stop   = diskstats_stop,
+       .start  = disk_seqf_start,
+       .next   = disk_seqf_next,
+       .stop   = disk_seqf_stop,
        .show   = diskstats_show
 };
 #endif /* CONFIG_PROC_FS */
 EXPORT_SYMBOL_GPL(genhd_media_change_notify);
 #endif  /*  0  */
 
-struct find_block {
-       const char *name;
-       int part;
-};
-
-static int match_id(struct device *dev, void *data)
+dev_t blk_lookup_devt(const char *name, int part)
 {
-       struct find_block *find = data;
+       dev_t devt = MKDEV(0, 0);
+       struct class_dev_iter iter;
+       struct device *dev;
 
-       if (dev->type != &disk_type)
-               return 0;
-       if (strcmp(dev->bus_id, find->name) == 0) {
+       class_dev_iter_init(&iter, &block_class, NULL, &disk_type);
+       while ((dev = class_dev_iter_next(&iter))) {
                struct gendisk *disk = dev_to_disk(dev);
-               if (find->part < disk->minors)
-                       return 1;
-       }
-       return 0;
-}
 
-dev_t blk_lookup_devt(const char *name, int part)
-{
-       struct device *dev;
-       dev_t devt = MKDEV(0, 0);
-       struct find_block find;
-
-       find.name = name;
-       find.part = part;
-       dev = class_find_device(&block_class, NULL, &find, match_id);
-       if (dev) {
-               put_device(dev);
-               devt = MKDEV(MAJOR(dev->devt),
-                            MINOR(dev->devt) + part);
+               if (!strcmp(dev->bus_id, name) && part < disk->minors) {
+                       devt = MKDEV(MAJOR(dev->devt),
+                                    MINOR(dev->devt) + part);
+                       break;
+               }
        }
-
+       class_dev_iter_exit(&iter);
        return devt;
 }
 EXPORT_SYMBOL(blk_lookup_devt);