[net-next-2.6.git] / drivers / s390 / char / tape_block.c

/*
 *  drivers/s390/char/tape_block.c
 *    block device frontend for tape device driver
 *
 *  S390 and zSeries version
 *    Copyright (C) 2001,2003 IBM Deutschland Entwicklung GmbH, IBM Corporation
 *    Author(s): Carsten Otte <cotte@de.ibm.com>
 *		 Tuan Ngo-Anh <ngoanh@de.ibm.com>
 *		 Martin Schwidefsky <schwidefsky@de.ibm.com>
 *		 Stefan Bader <shbader@de.ibm.com>
 */

#include <linux/fs.h>
#include <linux/module.h>
#include <linux/blkdev.h>
#include <linux/interrupt.h>
#include <linux/buffer_head.h>
#include <linux/kernel.h>

#include <asm/debug.h>

#define TAPE_DBF_AREA	tape_core_dbf

#include "tape.h"

#define PRINTK_HEADER "TAPE_BLOCK: "

#define TAPEBLOCK_MAX_SEC	100
#define TAPEBLOCK_MIN_REQUEUE	3

/*
 * 2003/11/25  Stefan Bader <shbader@de.ibm.com>
 *
 * In 2.5/2.6 the block device request function is very likely to be called
 * with disabled interrupts (e.g. generic_unplug_device). So the driver can't
 * just call any function that tries to allocate CCW requests from that con-
 * text since it might sleep. There are two choices to work around this:
 *	a) do not allocate with kmalloc but use its own memory pool
 *      b) take requests from the queue outside that context, knowing that
 *         allocation might sleep
 */

/*
 * file operation structure for tape block frontend
 */
static int tapeblock_open(struct block_device *, fmode_t);
static int tapeblock_release(struct gendisk *, fmode_t);
static int tapeblock_ioctl(struct block_device *, fmode_t, unsigned int,
				unsigned long);
static int tapeblock_medium_changed(struct gendisk *);
static int tapeblock_revalidate_disk(struct gendisk *);

static struct block_device_operations tapeblock_fops = {
	.owner		 = THIS_MODULE,
	.open		 = tapeblock_open,
	.release	 = tapeblock_release,
	.locked_ioctl           = tapeblock_ioctl,
	.media_changed   = tapeblock_medium_changed,
	.revalidate_disk = tapeblock_revalidate_disk,
};

static int tapeblock_major = 0;

static void
tapeblock_trigger_requeue(struct tape_device *device)
{
	/* Protect against rescheduling. */
	if (atomic_cmpxchg(&device->blk_data.requeue_scheduled, 0, 1) != 0)
		return;
	schedule_work(&device->blk_data.requeue_task);
}

/*
 * Post finished request.
 */
static void
tapeblock_end_request(struct request *req, int error)
{
	if (blk_end_request(req, error, blk_rq_bytes(req)))
		BUG();
}

static void
__tapeblock_end_request(struct tape_request *ccw_req, void *data)
{
	struct tape_device *device;
	struct request *req;

	DBF_LH(6, "__tapeblock_end_request()\n");

	device = ccw_req->device;
	req = (struct request *) data;
	tapeblock_end_request(req, (ccw_req->rc == 0) ? 0 : -EIO);
	if (ccw_req->rc == 0)
		/* Update position. */
		device->blk_data.block_position =
			(req->sector + req->nr_sectors) >> TAPEBLOCK_HSEC_S2B;
	else
		/* We lost the position information due to an error. */
		device->blk_data.block_position = -1;
	device->discipline->free_bread(ccw_req);
	if (!list_empty(&device->req_queue) ||
	    elv_next_request(device->blk_data.request_queue))
		tapeblock_trigger_requeue(device);
}

/*
 * Feed the tape device CCW queue with requests supplied in a list.
 */
static int
tapeblock_start_request(struct tape_device *device, struct request *req)
{
	struct tape_request *	ccw_req;
	int			rc;

	DBF_LH(6, "tapeblock_start_request(%p, %p)\n", device, req);

	ccw_req = device->discipline->bread(device, req);
	if (IS_ERR(ccw_req)) {
		DBF_EVENT(1, "TBLOCK: bread failed\n");
		tapeblock_end_request(req, -EIO);
		return PTR_ERR(ccw_req);
	}
	ccw_req->callback = __tapeblock_end_request;
	ccw_req->callback_data = (void *) req;
	ccw_req->retries = TAPEBLOCK_RETRIES;

	rc = tape_do_io_async(device, ccw_req);
	if (rc) {
		/*
		 * Start/enqueueing failed. No retries in
		 * this case.
		 */
		tapeblock_end_request(req, -EIO);
		device->discipline->free_bread(ccw_req);
	}

	return rc;
}

/*
 * Move requests from the block device request queue to the tape device ccw
 * queue.
 */
static void
tapeblock_requeue(struct work_struct *work) {
	struct tape_blk_data *	blkdat;
	struct tape_device *	device;
	struct request_queue *	queue;
	int			nr_queued;
	struct request *	req;
	struct list_head *	l;
	int			rc;

	blkdat = container_of(work, struct tape_blk_data, requeue_task);
	device = blkdat->device;
	if (!device)
		return;

	spin_lock_irq(get_ccwdev_lock(device->cdev));
	queue  = device->blk_data.request_queue;

	/* Count number of requests on ccw queue. */
	nr_queued = 0;
	list_for_each(l, &device->req_queue)
		nr_queued++;
	spin_unlock(get_ccwdev_lock(device->cdev));

	spin_lock_irq(&device->blk_data.request_queue_lock);
	while (
		!blk_queue_plugged(queue) &&
		elv_next_request(queue)   &&
		nr_queued < TAPEBLOCK_MIN_REQUEUE
	) {
		req = elv_next_request(queue);
		if (rq_data_dir(req) == WRITE) {
			DBF_EVENT(1, "TBLOCK: Rejecting write request\n");
			blkdev_dequeue_request(req);
			spin_unlock_irq(&device->blk_data.request_queue_lock);
			tapeblock_end_request(req, -EIO);
			spin_lock_irq(&device->blk_data.request_queue_lock);
			continue;
		}
		blkdev_dequeue_request(req);
		nr_queued++;
		spin_unlock_irq(&device->blk_data.request_queue_lock);
		rc = tapeblock_start_request(device, req);
		spin_lock_irq(&device->blk_data.request_queue_lock);
	}
	spin_unlock_irq(&device->blk_data.request_queue_lock);
	atomic_set(&device->blk_data.requeue_scheduled, 0);
}

/*
 * Tape request queue function. Called from ll_rw_blk.c
 */
static void
tapeblock_request_fn(struct request_queue *queue)
{
	struct tape_device *device;

	device = (struct tape_device *) queue->queuedata;
	DBF_LH(6, "tapeblock_request_fn(device=%p)\n", device);
	BUG_ON(device == NULL);
	tapeblock_trigger_requeue(device);
}

/*
 * This function is called for every new tapedevice
 */
int
tapeblock_setup_device(struct tape_device * device)
{
	struct tape_blk_data *	blkdat;
	struct gendisk *	disk;
	int			rc;

	blkdat = &device->blk_data;
	blkdat->device = device;
	spin_lock_init(&blkdat->request_queue_lock);
	atomic_set(&blkdat->requeue_scheduled, 0);

	blkdat->request_queue = blk_init_queue(
		tapeblock_request_fn,
		&blkdat->request_queue_lock
	);
	if (!blkdat->request_queue)
		return -ENOMEM;

	elevator_exit(blkdat->request_queue->elevator);
	rc = elevator_init(blkdat->request_queue, "noop");
	if (rc)
		goto cleanup_queue;

	blk_queue_hardsect_size(blkdat->request_queue, TAPEBLOCK_HSEC_SIZE);
	blk_queue_max_sectors(blkdat->request_queue, TAPEBLOCK_MAX_SEC);
	blk_queue_max_phys_segments(blkdat->request_queue, -1L);
	blk_queue_max_hw_segments(blkdat->request_queue, -1L);
	blk_queue_max_segment_size(blkdat->request_queue, -1L);
	blk_queue_segment_boundary(blkdat->request_queue, -1L);

	disk = alloc_disk(1);
	if (!disk) {
		rc = -ENOMEM;
		goto cleanup_queue;
	}

	disk->major = tapeblock_major;
	disk->first_minor = device->first_minor;
	disk->fops = &tapeblock_fops;
	disk->private_data = tape_get_device_reference(device);
	disk->queue = blkdat->request_queue;
	set_capacity(disk, 0);
	sprintf(disk->disk_name, "btibm%d",
		device->first_minor / TAPE_MINORS_PER_DEV);

	blkdat->disk = disk;
	blkdat->medium_changed = 1;
	blkdat->request_queue->queuedata = tape_get_device_reference(device);

	add_disk(disk);

	tape_get_device_reference(device);
	INIT_WORK(&blkdat->requeue_task, tapeblock_requeue);

	return 0;

cleanup_queue:
	blk_cleanup_queue(blkdat->request_queue);
	blkdat->request_queue = NULL;

	return rc;
}

void
tapeblock_cleanup_device(struct tape_device *device)
{
	flush_scheduled_work();
	tape_put_device(device);

	if (!device->blk_data.disk) {
		PRINT_ERR("(%s): No gendisk to clean up!\n",
			dev_name(&device->cdev->dev));
		goto cleanup_queue;
	}

	del_gendisk(device->blk_data.disk);
	device->blk_data.disk->private_data =
		tape_put_device(device->blk_data.disk->private_data);
	put_disk(device->blk_data.disk);

	device->blk_data.disk = NULL;
cleanup_queue:
	device->blk_data.request_queue->queuedata = tape_put_device(device);

	blk_cleanup_queue(device->blk_data.request_queue);
	device->blk_data.request_queue = NULL;
}

/*
 * Detect number of blocks of the tape.
 * FIXME: can we extent this to detect the blocks size as well ?
 */
static int
tapeblock_revalidate_disk(struct gendisk *disk)
{
	struct tape_device *	device;
	unsigned int		nr_of_blks;
	int			rc;

	device = (struct tape_device *) disk->private_data;
	BUG_ON(!device);

	if (!device->blk_data.medium_changed)
		return 0;

	PRINT_INFO("Detecting media size...\n");
	rc = tape_mtop(device, MTFSFM, 1);
	if (rc)
		return rc;

	rc = tape_mtop(device, MTTELL, 1);
	if (rc < 0)
		return rc;

	DBF_LH(3, "Image file ends at %d\n", rc);
	nr_of_blks = rc;

	/* This will fail for the first file. Catch the error by checking the
	 * position. */
	tape_mtop(device, MTBSF, 1);

	rc = tape_mtop(device, MTTELL, 1);
	if (rc < 0)
		return rc;

	if (rc > nr_of_blks)
		return -EINVAL;

	DBF_LH(3, "Image file starts at %d\n", rc);
	device->bof = rc;
	nr_of_blks -= rc;

	PRINT_INFO("Found %i blocks on media\n", nr_of_blks);
	set_capacity(device->blk_data.disk,
		nr_of_blks*(TAPEBLOCK_HSEC_SIZE/512));

	device->blk_data.block_position = 0;
	device->blk_data.medium_changed = 0;
	return 0;
}

static int
tapeblock_medium_changed(struct gendisk *disk)
{
	struct tape_device *device;

	device = (struct tape_device *) disk->private_data;
	DBF_LH(6, "tapeblock_medium_changed(%p) = %d\n",
		device, device->blk_data.medium_changed);

	return device->blk_data.medium_changed;
}

/*
 * Block frontend tape device open function.
 */
static int
tapeblock_open(struct block_device *bdev, fmode_t mode)
{
	struct gendisk *	disk = bdev->bd_disk;
	struct tape_device *	device;
	int			rc;

	device = tape_get_device_reference(disk->private_data);

	if (device->required_tapemarks) {
		DBF_EVENT(2, "TBLOCK: missing tapemarks\n");
		PRINT_ERR("TBLOCK: Refusing to open tape with missing"
			" end of file marks.\n");
		rc = -EPERM;
		goto put_device;
	}

	rc = tape_open(device);
	if (rc)
		goto put_device;

	rc = tapeblock_revalidate_disk(disk);
	if (rc)
		goto release;

	/*
	 * Note: The reference to <device> is hold until the release function
	 *       is called.
	 */
	tape_state_set(device, TS_BLKUSE);
	return 0;

release:
	tape_release(device);
 put_device:
	tape_put_device(device);
	return rc;
}

/*
 * Block frontend tape device release function.
 *
 * Note: One reference to the tape device was made by the open function. So
 *       we just get the pointer here and release the reference.
 */
static int
tapeblock_release(struct gendisk *disk, fmode_t mode)
{
	struct tape_device *device = disk->private_data;

	tape_state_set(device, TS_IN_USE);
	tape_release(device);
	tape_put_device(device);

	return 0;
}

/*
 * Support of some generic block device IOCTLs.
 */
static int
tapeblock_ioctl(
	struct block_device *	bdev,
	fmode_t			mode,
	unsigned int		command,
	unsigned long		arg
) {
	int rc;
	int minor;
	struct gendisk *disk = bdev->bd_disk;
	struct tape_device *device;

	rc     = 0;
	BUG_ON(!disk);
	device = disk->private_data;
	BUG_ON(!device);
	minor  = MINOR(bdev->bd_dev);

	DBF_LH(6, "tapeblock_ioctl(0x%0x)\n", command);
	DBF_LH(6, "device = %d:%d\n", tapeblock_major, minor);

	switch (command) {
		/* Refuse some IOCTL calls without complaining (mount). */
		case 0x5310:		/* CDROMMULTISESSION */
			rc = -EINVAL;
			break;
		default:
			PRINT_WARN("invalid ioctl 0x%x\n", command);
			rc = -EINVAL;
	}

	return rc;
}

/*
 * Initialize block device frontend.
 */
int
tapeblock_init(void)
{
	int rc;

	/* Register the tape major number to the kernel */
	rc = register_blkdev(tapeblock_major, "tBLK");
	if (rc < 0)
		return rc;

	if (tapeblock_major == 0)
		tapeblock_major = rc;
	PRINT_INFO("tape gets major %d for block device\n", tapeblock_major);
	return 0;
}

/*
 * Deregister major for block device frontend
 */
void
tapeblock_exit(void)
{
	unregister_blkdev(tapeblock_major, "tBLK");
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* drivers/s390/char/tape_block.c
	3	* block device frontend for tape device driver
	4	*
	5	* S390 and zSeries version
	6	* Copyright (C) 2001,2003 IBM Deutschland Entwicklung GmbH, IBM Corporation
	7	* Author(s): Carsten Otte <cotte@de.ibm.com>
	8	* Tuan Ngo-Anh <ngoanh@de.ibm.com>
	9	* Martin Schwidefsky <schwidefsky@de.ibm.com>
	10	* Stefan Bader <shbader@de.ibm.com>
	11	*/
	12
	13	#include <linux/fs.h>
1da177e4 LT	14	#include <linux/module.h>
	15	#include <linux/blkdev.h>
	16	#include <linux/interrupt.h>
	17	#include <linux/buffer_head.h>
c1637532	18	#include <linux/kernel.h>
1da177e4 LT	19
	20	#include <asm/debug.h>
	21
	22	#define TAPE_DBF_AREA tape_core_dbf
	23
	24	#include "tape.h"
	25
	26	#define PRINTK_HEADER "TAPE_BLOCK: "
	27
	28	#define TAPEBLOCK_MAX_SEC 100
	29	#define TAPEBLOCK_MIN_REQUEUE 3
	30
	31	/*
	32	* 2003/11/25 Stefan Bader <shbader@de.ibm.com>
	33	*
	34	* In 2.5/2.6 the block device request function is very likely to be called
	35	* with disabled interrupts (e.g. generic_unplug_device). So the driver can't
	36	* just call any function that tries to allocate CCW requests from that con-
	37	* text since it might sleep. There are two choices to work around this:
	38	* a) do not allocate with kmalloc but use its own memory pool
	39	* b) take requests from the queue outside that context, knowing that
	40	* allocation might sleep
	41	*/
	42
	43	/*
	44	* file operation structure for tape block frontend
	45	*/
4e999af9 AV	46	static int tapeblock_open(struct block_device *, fmode_t);
	47	static int tapeblock_release(struct gendisk *, fmode_t);
	48	static int tapeblock_ioctl(struct block_device *, fmode_t, unsigned int,
1da177e4 LT	49	unsigned long);
	50	static int tapeblock_medium_changed(struct gendisk *);
	51	static int tapeblock_revalidate_disk(struct gendisk *);
	52
	53	static struct block_device_operations tapeblock_fops = {
	54	.owner = THIS_MODULE,
4e999af9 AV	55	.open = tapeblock_open,
	56	.release = tapeblock_release,
	57	.locked_ioctl = tapeblock_ioctl,
1da177e4 LT	58	.media_changed = tapeblock_medium_changed,
	59	.revalidate_disk = tapeblock_revalidate_disk,
	60	};
	61
	62	static int tapeblock_major = 0;
	63
	64	static void
	65	tapeblock_trigger_requeue(struct tape_device *device)
	66	{
	67	/* Protect against rescheduling. */
973bd993	68	if (atomic_cmpxchg(&device->blk_data.requeue_scheduled, 0, 1) != 0)
1da177e4 LT	69	return;
	70	schedule_work(&device->blk_data.requeue_task);
	71	}
	72
	73	/*
	74	* Post finished request.
	75	*/
4d284cac	76	static void
4c4e2148	77	tapeblock_end_request(struct request *req, int error)
1da177e4	78	{
7a4a1ccd	79	if (blk_end_request(req, error, blk_rq_bytes(req)))
1da177e4	80	BUG();
1da177e4 LT	81	}
	82
	83	static void
	84	__tapeblock_end_request(struct tape_request ccw_req, void data)
	85	{
	86	struct tape_device *device;
	87	struct request *req;
	88
	89	DBF_LH(6, "__tapeblock_end_request()\n");
	90
	91	device = ccw_req->device;
	92	req = (struct request *) data;
4c4e2148	93	tapeblock_end_request(req, (ccw_req->rc == 0) ? 0 : -EIO);
1da177e4 LT	94	if (ccw_req->rc == 0)
	95	/* Update position. */
	96	device->blk_data.block_position =
	97	(req->sector + req->nr_sectors) >> TAPEBLOCK_HSEC_S2B;
	98	else
	99	/* We lost the position information due to an error. */
	100	device->blk_data.block_position = -1;
	101	device->discipline->free_bread(ccw_req);
	102	if (!list_empty(&device->req_queue) \|\|
	103	elv_next_request(device->blk_data.request_queue))
	104	tapeblock_trigger_requeue(device);
	105	}
	106
	107	/*
	108	* Feed the tape device CCW queue with requests supplied in a list.
	109	*/
4d284cac	110	static int
1da177e4 LT	111	tapeblock_start_request(struct tape_device device, struct request req)
	112	{
	113	struct tape_request * ccw_req;
	114	int rc;
	115
	116	DBF_LH(6, "tapeblock_start_request(%p, %p)\n", device, req);
	117
	118	ccw_req = device->discipline->bread(device, req);
	119	if (IS_ERR(ccw_req)) {
	120	DBF_EVENT(1, "TBLOCK: bread failed\n");
4c4e2148	121	tapeblock_end_request(req, -EIO);
1da177e4 LT	122	return PTR_ERR(ccw_req);
	123	}
	124	ccw_req->callback = __tapeblock_end_request;
	125	ccw_req->callback_data = (void *) req;
	126	ccw_req->retries = TAPEBLOCK_RETRIES;
	127
	128	rc = tape_do_io_async(device, ccw_req);
	129	if (rc) {
	130	/*
	131	* Start/enqueueing failed. No retries in
	132	* this case.
	133	*/
4c4e2148	134	tapeblock_end_request(req, -EIO);
1da177e4 LT	135	device->discipline->free_bread(ccw_req);
	136	}
	137
	138	return rc;
	139	}
	140
	141	/*
	142	* Move requests from the block device request queue to the tape device ccw
	143	* queue.
	144	*/
	145	static void
c1637532 MS	146	tapeblock_requeue(struct work_struct *work) {
c1637532 MS	147	struct tape_blk_data * blkdat;
1da177e4	148	struct tape_device * device;
165125e1	149	struct request_queue * queue;
1da177e4 LT	150	int nr_queued;
	151	struct request * req;
	152	struct list_head * l;
	153	int rc;
	154
c1637532 MS	155	blkdat = container_of(work, struct tape_blk_data, requeue_task);
c1637532 MS	156	device = blkdat->device;
1da177e4 LT	157	if (!device)
	158	return;
	159
	160	spin_lock_irq(get_ccwdev_lock(device->cdev));
	161	queue = device->blk_data.request_queue;
	162
	163	/* Count number of requests on ccw queue. */
	164	nr_queued = 0;
	165	list_for_each(l, &device->req_queue)
	166	nr_queued++;
	167	spin_unlock(get_ccwdev_lock(device->cdev));
	168
7a4a1ccd	169	spin_lock_irq(&device->blk_data.request_queue_lock);
1da177e4 LT	170	while (
	171	!blk_queue_plugged(queue) &&
	172	elv_next_request(queue) &&
	173	nr_queued < TAPEBLOCK_MIN_REQUEUE
	174	) {
	175	req = elv_next_request(queue);
	176	if (rq_data_dir(req) == WRITE) {
	177	DBF_EVENT(1, "TBLOCK: Rejecting write request\n");
	178	blkdev_dequeue_request(req);
7a4a1ccd	179	spin_unlock_irq(&device->blk_data.request_queue_lock);
4c4e2148	180	tapeblock_end_request(req, -EIO);
7a4a1ccd	181	spin_lock_irq(&device->blk_data.request_queue_lock);
1da177e4 LT	182	continue;
1da177e4 LT	183	}
f71ad62a MH	184	blkdev_dequeue_request(req);
f71ad62a MH	185	nr_queued++;
1da177e4 LT	186	spin_unlock_irq(&device->blk_data.request_queue_lock);
	187	rc = tapeblock_start_request(device, req);
	188	spin_lock_irq(&device->blk_data.request_queue_lock);
1da177e4 LT	189	}
	190	spin_unlock_irq(&device->blk_data.request_queue_lock);
	191	atomic_set(&device->blk_data.requeue_scheduled, 0);
	192	}
	193
	194	/*
	195	* Tape request queue function. Called from ll_rw_blk.c
	196	*/
	197	static void
165125e1	198	tapeblock_request_fn(struct request_queue *queue)
1da177e4 LT	199	{
	200	struct tape_device *device;
	201
	202	device = (struct tape_device *) queue->queuedata;
	203	DBF_LH(6, "tapeblock_request_fn(device=%p)\n", device);
3a8dc893	204	BUG_ON(device == NULL);
1da177e4 LT	205	tapeblock_trigger_requeue(device);
	206	}
	207
	208	/*
	209	* This function is called for every new tapedevice
	210	*/
	211	int
	212	tapeblock_setup_device(struct tape_device * device)
	213	{
	214	struct tape_blk_data * blkdat;
	215	struct gendisk * disk;
	216	int rc;
	217
	218	blkdat = &device->blk_data;
c1637532	219	blkdat->device = device;
1da177e4 LT	220	spin_lock_init(&blkdat->request_queue_lock);
	221	atomic_set(&blkdat->requeue_scheduled, 0);
	222
	223	blkdat->request_queue = blk_init_queue(
	224	tapeblock_request_fn,
	225	&blkdat->request_queue_lock
	226	);
	227	if (!blkdat->request_queue)
	228	return -ENOMEM;
	229
	230	elevator_exit(blkdat->request_queue->elevator);
	231	rc = elevator_init(blkdat->request_queue, "noop");
	232	if (rc)
	233	goto cleanup_queue;
	234
	235	blk_queue_hardsect_size(blkdat->request_queue, TAPEBLOCK_HSEC_SIZE);
	236	blk_queue_max_sectors(blkdat->request_queue, TAPEBLOCK_MAX_SEC);
	237	blk_queue_max_phys_segments(blkdat->request_queue, -1L);
	238	blk_queue_max_hw_segments(blkdat->request_queue, -1L);
	239	blk_queue_max_segment_size(blkdat->request_queue, -1L);
	240	blk_queue_segment_boundary(blkdat->request_queue, -1L);
	241
	242	disk = alloc_disk(1);
	243	if (!disk) {
	244	rc = -ENOMEM;
	245	goto cleanup_queue;
	246	}
	247
	248	disk->major = tapeblock_major;
	249	disk->first_minor = device->first_minor;
	250	disk->fops = &tapeblock_fops;
	251	disk->private_data = tape_get_device_reference(device);
	252	disk->queue = blkdat->request_queue;
	253	set_capacity(disk, 0);
	254	sprintf(disk->disk_name, "btibm%d",
	255	device->first_minor / TAPE_MINORS_PER_DEV);
	256
	257	blkdat->disk = disk;
	258	blkdat->medium_changed = 1;
	259	blkdat->request_queue->queuedata = tape_get_device_reference(device);
	260
	261	add_disk(disk);
	262
c1637532 MS	263	tape_get_device_reference(device);
c1637532 MS	264	INIT_WORK(&blkdat->requeue_task, tapeblock_requeue);
1da177e4 LT	265
	266	return 0;
	267
	268	cleanup_queue:
	269	blk_cleanup_queue(blkdat->request_queue);
	270	blkdat->request_queue = NULL;
	271
	272	return rc;
	273	}
	274
	275	void
	276	tapeblock_cleanup_device(struct tape_device *device)
	277	{
	278	flush_scheduled_work();
c1637532	279	tape_put_device(device);
1da177e4 LT	280
	281	if (!device->blk_data.disk) {
	282	PRINT_ERR("(%s): No gendisk to clean up!\n",
2a0217d5	283	dev_name(&device->cdev->dev));
1da177e4 LT	284	goto cleanup_queue;
	285	}
	286
	287	del_gendisk(device->blk_data.disk);
	288	device->blk_data.disk->private_data =
	289	tape_put_device(device->blk_data.disk->private_data);
	290	put_disk(device->blk_data.disk);
	291
	292	device->blk_data.disk = NULL;
	293	cleanup_queue:
	294	device->blk_data.request_queue->queuedata = tape_put_device(device);
	295
	296	blk_cleanup_queue(device->blk_data.request_queue);
	297	device->blk_data.request_queue = NULL;
	298	}
	299
	300	/*
	301	* Detect number of blocks of the tape.
	302	* FIXME: can we extent this to detect the blocks size as well ?
	303	*/
	304	static int
	305	tapeblock_revalidate_disk(struct gendisk *disk)
	306	{
	307	struct tape_device * device;
	308	unsigned int nr_of_blks;
	309	int rc;
	310
	311	device = (struct tape_device *) disk->private_data;
3a8dc893	312	BUG_ON(!device);
1da177e4 LT	313
	314	if (!device->blk_data.medium_changed)
	315	return 0;
	316
	317	PRINT_INFO("Detecting media size...\n");
	318	rc = tape_mtop(device, MTFSFM, 1);
	319	if (rc)
	320	return rc;
	321
	322	rc = tape_mtop(device, MTTELL, 1);
	323	if (rc < 0)
	324	return rc;
	325
	326	DBF_LH(3, "Image file ends at %d\n", rc);
	327	nr_of_blks = rc;
	328
	329	/* This will fail for the first file. Catch the error by checking the
	330	* position. */
	331	tape_mtop(device, MTBSF, 1);
	332
	333	rc = tape_mtop(device, MTTELL, 1);
	334	if (rc < 0)
	335	return rc;
	336
	337	if (rc > nr_of_blks)
	338	return -EINVAL;
	339
	340	DBF_LH(3, "Image file starts at %d\n", rc);
	341	device->bof = rc;
	342	nr_of_blks -= rc;
	343
	344	PRINT_INFO("Found %i blocks on media\n", nr_of_blks);
	345	set_capacity(device->blk_data.disk,
	346	nr_of_blks*(TAPEBLOCK_HSEC_SIZE/512));
	347
	348	device->blk_data.block_position = 0;
	349	device->blk_data.medium_changed = 0;
	350	return 0;
	351	}
	352
	353	static int
	354	tapeblock_medium_changed(struct gendisk *disk)
	355	{
	356	struct tape_device *device;
	357
	358	device = (struct tape_device *) disk->private_data;
	359	DBF_LH(6, "tapeblock_medium_changed(%p) = %d\n",
	360	device, device->blk_data.medium_changed);
	361
	362	return device->blk_data.medium_changed;
	363	}
	364
	365	/*
	366	* Block frontend tape device open function.
	367	*/
	368	static int
4e999af9	369	tapeblock_open(struct block_device *bdev, fmode_t mode)
1da177e4	370	{
4e999af9	371	struct gendisk * disk = bdev->bd_disk;
1da177e4 LT	372	struct tape_device * device;
	373	int rc;
	374
1da177e4 LT	375	device = tape_get_device_reference(disk->private_data);
	376
	377	if (device->required_tapemarks) {
	378	DBF_EVENT(2, "TBLOCK: missing tapemarks\n");
	379	PRINT_ERR("TBLOCK: Refusing to open tape with missing"
	380	" end of file marks.\n");
	381	rc = -EPERM;
	382	goto put_device;
	383	}
	384
	385	rc = tape_open(device);
	386	if (rc)
	387	goto put_device;
	388
	389	rc = tapeblock_revalidate_disk(disk);
	390	if (rc)
	391	goto release;
	392
	393	/*
	394	* Note: The reference to <device> is hold until the release function
	395	* is called.
	396	*/
	397	tape_state_set(device, TS_BLKUSE);
	398	return 0;
	399
	400	release:
	401	tape_release(device);
	402	put_device:
	403	tape_put_device(device);
	404	return rc;
	405	}
	406
	407	/*
	408	* Block frontend tape device release function.
	409	*
	410	* Note: One reference to the tape device was made by the open function. So
	411	* we just get the pointer here and release the reference.
	412	*/
	413	static int
4e999af9	414	tapeblock_release(struct gendisk *disk, fmode_t mode)
1da177e4	415	{
1da177e4 LT	416	struct tape_device *device = disk->private_data;
	417
	418	tape_state_set(device, TS_IN_USE);
	419	tape_release(device);
	420	tape_put_device(device);
	421
	422	return 0;
	423	}
	424
	425	/*
	426	* Support of some generic block device IOCTLs.
	427	*/
	428	static int
	429	tapeblock_ioctl(
4e999af9 AV	430	struct block_device * bdev,
4e999af9 AV	431	fmode_t mode,
1da177e4 LT	432	unsigned int command,
	433	unsigned long arg
	434	) {
	435	int rc;
	436	int minor;
4e999af9	437	struct gendisk *disk = bdev->bd_disk;
f976069a	438	struct tape_device *device;
1da177e4 LT	439
1da177e4 LT	440	rc = 0;
3a8dc893	441	BUG_ON(!disk);
1da177e4	442	device = disk->private_data;
3a8dc893	443	BUG_ON(!device);
4e999af9	444	minor = MINOR(bdev->bd_dev);
1da177e4 LT	445
	446	DBF_LH(6, "tapeblock_ioctl(0x%0x)\n", command);
	447	DBF_LH(6, "device = %d:%d\n", tapeblock_major, minor);
	448
	449	switch (command) {
	450	/* Refuse some IOCTL calls without complaining (mount). */
	451	case 0x5310: /* CDROMMULTISESSION */
	452	rc = -EINVAL;
	453	break;
	454	default:
	455	PRINT_WARN("invalid ioctl 0x%x\n", command);
	456	rc = -EINVAL;
	457	}
	458
	459	return rc;
	460	}
	461
	462	/*
	463	* Initialize block device frontend.
	464	*/
	465	int
	466	tapeblock_init(void)
	467	{
	468	int rc;
	469
	470	/* Register the tape major number to the kernel */
	471	rc = register_blkdev(tapeblock_major, "tBLK");
	472	if (rc < 0)
	473	return rc;
	474
	475	if (tapeblock_major == 0)
	476	tapeblock_major = rc;
	477	PRINT_INFO("tape gets major %d for block device\n", tapeblock_major);
	478	return 0;
	479	}
	480
	481	/*
	482	* Deregister major for block device frontend
	483	*/
	484	void
	485	tapeblock_exit(void)
	486	{
	487	unregister_blkdev(tapeblock_major, "tBLK");
	488	}