block: don't depend on consecutive minor space
* Implement disk_devt() and part_devt() and use them to directly
access devt instead of computing it from ->major and ->first_minor.
Note that all references to ->major and ->first_minor outside of
block layer is used to determine devt of the disk (the part0) and as
->major and ->first_minor will continue to represent devt for the
disk, converting these users aren't strictly necessary. However,
convert them for consistency.
* Implement disk_max_parts() to avoid directly deferencing
genhd->minors.
* Update bdget_disk() such that it doesn't assume consecutive minor
space.
* Move devt computation from register_disk() to add_disk() and make it
the only one (all other usages use the initially determined value).
These changes clean up the code and will help disk->part dereference
fix and extended block device numbers.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index d1723c0..0ff7532 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -111,10 +111,14 @@
#define GENHD_FL_FAIL 64
struct gendisk {
+ /* major, first_minor and minors are input parameters only,
+ * don't use directly. Use disk_devt() and disk_max_parts().
+ */
int major; /* major number of driver */
int first_minor;
int minors; /* maximum number of minors, =1 for
* disks that can't be partitioned. */
+
char disk_name[32]; /* name of major driver */
struct hd_struct **part; /* [indexed by minor - 1] */
struct block_device_operations *fops;
@@ -152,6 +156,21 @@
return NULL;
}
+static inline int disk_max_parts(struct gendisk *disk)
+{
+ return disk->minors - 1;
+}
+
+static inline dev_t disk_devt(struct gendisk *disk)
+{
+ return disk->dev.devt;
+}
+
+static inline dev_t part_devt(struct hd_struct *part)
+{
+ return part->dev.devt;
+}
+
/*
* Macros to operate on percpu disk statistics:
*
@@ -163,7 +182,7 @@
{
struct hd_struct *part;
int i;
- for (i = 0; i < gendiskp->minors - 1; i++) {
+ for (i = 0; i < disk_max_parts(gendiskp); i++) {
part = gendiskp->part[i];
if (part && part->start_sect <= sector
&& sector < part->start_sect + part->nr_sects)
@@ -366,6 +385,7 @@
extern void del_gendisk(struct gendisk *gp);
extern void unlink_gendisk(struct gendisk *gp);
extern struct gendisk *get_gendisk(dev_t dev, int *partno);
+extern struct block_device *bdget_disk(struct gendisk *disk, int partno);
extern void set_device_ro(struct block_device *bdev, int flag);
extern void set_disk_ro(struct gendisk *disk, int flag);
@@ -553,11 +573,6 @@
void *data);
extern void blk_unregister_region(dev_t devt, unsigned long range);
-static inline struct block_device *bdget_disk(struct gendisk *disk, int partno)
-{
- return bdget(MKDEV(disk->major, disk->first_minor) + partno);
-}
-
#else /* CONFIG_BLOCK */
static inline void printk_all_partitions(void) { }