block: move __dev from disk to part0

Move disk->__dev to part0->__dev.  This simplifies bdget_disk() and
lookup_devt() and allows common sysfs attributes to be unified.
part_to_disk() is updated to handle part0 -> disk.

Updated to include a fix from Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>,
he writes:

"part0 is a "special" partition and doesn't need to have capacity set - this
fixes regression caused by "block: move __dev from disk to part0" commit."

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

1 files changed, 8 insertions, 5 deletions

diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index 1cf828148ec6..ff293ec8b3f7 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -16,9 +16,9 @@
 #ifdef CONFIG_BLOCK
 
 #define kobj_to_dev(k)          container_of((k), struct device, kobj)
-#define dev_to_disk(device)     container_of((device), struct gendisk, __dev)
+#define dev_to_disk(device)     container_of((device), struct gendisk, part0.__dev)
 #define dev_to_part(device)     container_of((device), struct hd_struct, __dev)
-#define disk_to_dev(disk)       (&((disk)->__dev))
+#define disk_to_dev(disk)       (&(disk)->part0.__dev)
 #define part_to_dev(part)       (&((part)->__dev))
 
 extern struct device_type part_type;
@@ -141,7 +141,6 @@ struct gendisk {
 
         int flags;
         struct device *driverfs_dev;  // FIXME: remove
-        struct device __dev;
         struct kobject *holder_dir;
         struct kobject *slave_dir;
 
@@ -164,8 +163,12 @@ struct gendisk {
 
 static inline struct gendisk *part_to_disk(struct hd_struct *part)
 {
-        if (likely(part))
-                return dev_to_disk(part_to_dev(part)->parent);
+        if (likely(part)) {
+                if (part->partno)
+                        return dev_to_disk(part_to_dev(part)->parent);
+                else
+                        return dev_to_disk(part_to_dev(part));
+        }
         return NULL;
 }