/*
* gendisk handling
*/
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/genhd.h>
#include <linux/kdev_t.h>
#include <linux/kernel.h>
#include <linux/blkdev.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/slab.h>
#include <linux/kmod.h>
#include <linux/kobj_map.h>
#include <linux/buffer_head.h>
#include <linux/mutex.h>
#include <linux/idr.h>
#include "blk.h"
static DEFINE_MUTEX(block_class_lock);
struct kobject *block_depr;
/* for extended dynamic devt allocation, currently only one major is used */
#define MAX_EXT_DEVT (1 << MINORBITS)
/* For extended devt allocation. ext_devt_mutex prevents look up
* results from going away underneath its user.
*/
static DEFINE_MUTEX(ext_devt_mutex);
static DEFINE_IDR(ext_devt_idr);
static struct device_type disk_type;
/**
* disk_get_part - get partition
* @disk: disk to look partition from
* @partno: partition number
*
* Look for partition @partno from @disk. If found, increment
* reference count and return it.
*
* CONTEXT:
* Don't care.
*
* RETURNS:
* Pointer to the found partition on success, NULL if not found.
*/
struct hd_struct *disk_get_part(struct gendisk *disk, int partno)
{
struct hd_struct *part = NULL;
struct disk_part_tbl *ptbl;
if (unlikely(partno < 0))
return NULL;
rcu_read_lock();
ptbl = rcu_dereference(disk->part_tbl);
if (likely(partno < ptbl->len)) {
part = rcu_dereference(ptbl->part[partno]);
if (part)
get_device(part_to_dev(part));
}
rcu_read_unlock();
return part;
}
EXPORT_SYMBOL_GPL(disk_get_part);
/**
* disk_part_iter_init - initialize partition iterator
* @piter: iterator to initialize
* @disk: disk to iterate over
* @flags: DISK_PITER_* flags
*
* Initialize @piter so that it iterates over partitions of @disk.
*
* CONTEXT:
* Don't care.
*/
void disk_part_iter_init(struct disk_part_iter *piter, struct gendisk *disk,
unsigned int flags)
{
struct disk_part_tbl *ptbl;
rcu_read_lock();
ptbl = rcu_dereference(disk->part_tbl);
piter->disk = disk;
piter->part = NULL;
if (flags & DISK_PITER_REVERSE)
piter->idx = ptbl->len - 1;
else if (flags & (DISK_PITER_INCL_PART0 | DISK_PITER_INCL_EMPTY_PART0))
piter->idx = 0;
else
piter->idx = 1;
piter->flags = flags;
rcu_read_unlock();
}
EXPORT_SYMBOL_GPL(disk_part_iter_init);
/**
* disk_part_iter_next - proceed iterator to the next partition and return it
* @piter: iterator of interest
*
* Proceed @piter to the next partition and return it.
*
* CONTEXT:
* Don't care.
*/
struct hd_struct *disk_part_iter_next(struct disk_part_iter *piter)
{
struct 