Commit 7cc178a6 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Jens Axboe
Browse files

brd: use __register_blkdev to allocate devices on demand 



Use the simpler mechanism attached to major_name to allocate a brd device
when a currently unregistered minor is accessed.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarHannes Reinecke <hare@suse.de>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 996e509b

drivers/block/brd.c

+11 −28
Original line number Diff line number Diff line
@@ -426,14 +426,15 @@ static void brd_free(struct brd_device *brd) 
	kfree(brd);

}



static struct brd_device *brd_init_one(int i, bool *new)

static void brd_probe(dev_t dev)

{

	struct brd_device *brd;

	int i = MINOR(dev) / max_part;



	*new = false;

	mutex_lock(&brd_devices_mutex);

	list_for_each_entry(brd, &brd_devices, brd_list) {

		if (brd->brd_number == i)

			goto out;

			goto out_unlock;

	}



	brd = brd_alloc(i);
@@ -442,9 +443,9 @@ static struct brd_device *brd_init_one(int i, bool *new) 
		add_disk(brd->brd_disk);

		list_add_tail(&brd->brd_list, &brd_devices);

	}

	*new = true;

out:

	return brd;



out_unlock:

	mutex_unlock(&brd_devices_mutex);

}



static void brd_del_one(struct brd_device *brd)
@@ -454,23 +455,6 @@ static void brd_del_one(struct brd_device *brd) 
	brd_free(brd);

}



static struct kobject *brd_probe(dev_t dev, int *part, void *data)

{

	struct brd_device *brd;

	struct kobject *kobj;

	bool new;



	mutex_lock(&brd_devices_mutex);

	brd = brd_init_one(MINOR(dev) / max_part, &new);

	kobj = brd ? get_disk_and_module(brd->brd_disk) : NULL;

	mutex_unlock(&brd_devices_mutex);



	if (new)

		*part = 0;



	return kobj;

}



static inline void brd_check_and_reset_par(void)

{

	if (unlikely(!max_part))
@@ -510,11 +494,12 @@ static int __init brd_init(void) 
	 *	dynamically.

	 */



	if (register_blkdev(RAMDISK_MAJOR, "ramdisk"))

	if (__register_blkdev(RAMDISK_MAJOR, "ramdisk", brd_probe))

		return -EIO;



	brd_check_and_reset_par();



	mutex_lock(&brd_devices_mutex);

	for (i = 0; i < rd_nr; i++) {

		brd = brd_alloc(i);

		if (!brd)
@@ -532,9 +517,7 @@ static int __init brd_init(void) 
		brd->brd_disk->queue = brd->brd_queue;

		add_disk(brd->brd_disk);

	}



	blk_register_region(MKDEV(RAMDISK_MAJOR, 0), 1UL << MINORBITS,

				  THIS_MODULE, brd_probe, NULL, NULL);

	mutex_unlock(&brd_devices_mutex);



	pr_info("brd: module loaded\n");

	return 0;
@@ -544,6 +527,7 @@ static int __init brd_init(void) 
		list_del(&brd->brd_list);

		brd_free(brd);

	}

	mutex_unlock(&brd_devices_mutex);

	unregister_blkdev(RAMDISK_MAJOR, "ramdisk");



	pr_info("brd: module NOT loaded !!!\n");
@@ -557,7 +541,6 @@ static void __exit brd_exit(void) 
	list_for_each_entry_safe(brd, next, &brd_devices, brd_list)

		brd_del_one(brd);



	blk_unregister_region(MKDEV(RAMDISK_MAJOR, 0), 1UL << MINORBITS);

	unregister_blkdev(RAMDISK_MAJOR, "ramdisk");



	pr_info("brd: module unloaded\n");