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>

diff --git a/block/genhd.c b/block/genhd.c
index 65b7386..36b9f1b 100644 (file)
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -537,22 +537,15 @@ struct gendisk *get_gendisk(dev_t devt, int *partno)
  */
 extern struct block_device *bdget_disk(struct gendisk *disk, int partno)
 {
-       dev_t devt = MKDEV(0, 0);
+       struct hd_struct *part;
+       struct block_device *bdev = NULL;
 
-       if (partno == 0)
-               devt = disk_devt(disk);
-       else {
-               struct hd_struct *part;
+       part = disk_get_part(disk, partno);
+       if (part && (part->nr_sects || partno == 0))
+               bdev = bdget(part_devt(part));
+       disk_put_part(part);
 
-               part = disk_get_part(disk, partno);
-               if (part && part->nr_sects)
-                       devt = part_devt(part);
-               disk_put_part(part);
-       }
-
-       if (likely(devt != MKDEV(0, 0)))
-               return bdget(devt);
-       return NULL;
+       return bdev;
 }
 EXPORT_SYMBOL(bdget_disk);
 
@@ -1000,27 +993,18 @@ dev_t blk_lookup_devt(const char *name, int partno)
        class_dev_iter_init(&iter, &block_class, NULL, &disk_type);
        while ((dev = class_dev_iter_next(&iter))) {
                struct gendisk *disk = dev_to_disk(dev);
+               struct hd_struct *part;
 
                if (strcmp(dev->bus_id, name))
                        continue;
-               if (partno < 0 || partno >= disk_max_parts(disk))
-                       continue;
-
-               if (partno == 0)
-                       devt = disk_devt(disk);
-               else {
-                       struct hd_struct *part;
-
-                       part = disk_get_part(disk, partno);
-                       if (!part || !part->nr_sects) {
-                               disk_put_part(part);
-                               continue;
-                       }
 
+               part = disk_get_part(disk, partno);
+               if (part && (part->nr_sects || partno == 0)) {
                        devt = part_devt(part);
                        disk_put_part(part);
+                       break;
                }
-               break;
+               disk_put_part(part);
        }
        class_dev_iter_exit(&iter);
        return devt;

diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index 1cf8281..ff293ec 100644 (file)
--- 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;
 }