[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>
 */

#define KMSG_COMPONENT "tape"

#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 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 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;
	blk_end_request_all(req, (ccw_req->rc == 0) ? 0 : -EIO);
	if (ccw_req->rc == 0)
		/* Update position. */
		device->blk_data.block_position =
		  (blk_rq_pos(req) + blk_rq_sectors(req)) >> 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");
		blk_end_request_all(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.
		 */
		blk_end_request_all(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);
			blk_end_request_all(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) {
		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;

	dev_info(&device->cdev->dev, "Determining the size of the recorded "
		"area...\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;

	dev_info(&device->cdev->dev, "The size of the recorded area is %i "
		"blocks\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");
		dev_warn(&device->cdev->dev, "Opening the tape failed because"
			" of 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:
			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;
	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
ab640db0 CO	13	#define KMSG_COMPONENT "tape"
ab640db0 CO	14
1da177e4	15	#include <linux/fs.h>
1da177e4 LT	16	#include <linux/module.h>
	17	#include <linux/blkdev.h>
	18	#include <linux/interrupt.h>
	19	#include <linux/buffer_head.h>
c1637532	20	#include <linux/kernel.h>
1da177e4 LT	21
	22	#include <asm/debug.h>
	23
	24	#define TAPE_DBF_AREA tape_core_dbf
	25
	26	#include "tape.h"
	27
1da177e4 LT	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	*/
1da177e4 LT	76	static void
	77	__tapeblock_end_request(struct tape_request ccw_req, void data)
	78	{
	79	struct tape_device *device;
	80	struct request *req;
	81
	82	DBF_LH(6, "__tapeblock_end_request()\n");
	83
	84	device = ccw_req->device;
	85	req = (struct request *) data;
40cbbb78	86	blk_end_request_all(req, (ccw_req->rc == 0) ? 0 : -EIO);
1da177e4 LT	87	if (ccw_req->rc == 0)
	88	/* Update position. */
	89	device->blk_data.block_position =
83096ebf	90	(blk_rq_pos(req) + blk_rq_sectors(req)) >> TAPEBLOCK_HSEC_S2B;
1da177e4 LT	91	else
	92	/* We lost the position information due to an error. */
	93	device->blk_data.block_position = -1;
	94	device->discipline->free_bread(ccw_req);
	95	if (!list_empty(&device->req_queue) \|\|
	96	elv_next_request(device->blk_data.request_queue))
	97	tapeblock_trigger_requeue(device);
	98	}
	99
	100	/*
	101	* Feed the tape device CCW queue with requests supplied in a list.
	102	*/
4d284cac	103	static int
1da177e4 LT	104	tapeblock_start_request(struct tape_device device, struct request req)
	105	{
	106	struct tape_request * ccw_req;
	107	int rc;
	108
	109	DBF_LH(6, "tapeblock_start_request(%p, %p)\n", device, req);
	110
	111	ccw_req = device->discipline->bread(device, req);
	112	if (IS_ERR(ccw_req)) {
	113	DBF_EVENT(1, "TBLOCK: bread failed\n");
40cbbb78	114	blk_end_request_all(req, -EIO);
1da177e4 LT	115	return PTR_ERR(ccw_req);
	116	}
	117	ccw_req->callback = __tapeblock_end_request;
	118	ccw_req->callback_data = (void *) req;
	119	ccw_req->retries = TAPEBLOCK_RETRIES;
	120
	121	rc = tape_do_io_async(device, ccw_req);
	122	if (rc) {
	123	/*
	124	* Start/enqueueing failed. No retries in
	125	* this case.
	126	*/
40cbbb78	127	blk_end_request_all(req, -EIO);
1da177e4 LT	128	device->discipline->free_bread(ccw_req);
	129	}
	130
	131	return rc;
	132	}
	133
	134	/*
	135	* Move requests from the block device request queue to the tape device ccw
	136	* queue.
	137	*/
	138	static void
c1637532 MS	139	tapeblock_requeue(struct work_struct *work) {
c1637532 MS	140	struct tape_blk_data * blkdat;
1da177e4	141	struct tape_device * device;
165125e1	142	struct request_queue * queue;
1da177e4 LT	143	int nr_queued;
	144	struct request * req;
	145	struct list_head * l;
	146	int rc;
	147
c1637532 MS	148	blkdat = container_of(work, struct tape_blk_data, requeue_task);
c1637532 MS	149	device = blkdat->device;
1da177e4 LT	150	if (!device)
	151	return;
	152
	153	spin_lock_irq(get_ccwdev_lock(device->cdev));
	154	queue = device->blk_data.request_queue;
	155
	156	/* Count number of requests on ccw queue. */
	157	nr_queued = 0;
	158	list_for_each(l, &device->req_queue)
	159	nr_queued++;
	160	spin_unlock(get_ccwdev_lock(device->cdev));
	161
7a4a1ccd	162	spin_lock_irq(&device->blk_data.request_queue_lock);
1da177e4 LT	163	while (
	164	!blk_queue_plugged(queue) &&
	165	elv_next_request(queue) &&
	166	nr_queued < TAPEBLOCK_MIN_REQUEUE
	167	) {
	168	req = elv_next_request(queue);
	169	if (rq_data_dir(req) == WRITE) {
	170	DBF_EVENT(1, "TBLOCK: Rejecting write request\n");
	171	blkdev_dequeue_request(req);
7a4a1ccd	172	spin_unlock_irq(&device->blk_data.request_queue_lock);
40cbbb78	173	blk_end_request_all(req, -EIO);
7a4a1ccd	174	spin_lock_irq(&device->blk_data.request_queue_lock);
1da177e4 LT	175	continue;
1da177e4 LT	176	}
f71ad62a MH	177	blkdev_dequeue_request(req);
f71ad62a MH	178	nr_queued++;
1da177e4 LT	179	spin_unlock_irq(&device->blk_data.request_queue_lock);
	180	rc = tapeblock_start_request(device, req);
	181	spin_lock_irq(&device->blk_data.request_queue_lock);
1da177e4 LT	182	}
	183	spin_unlock_irq(&device->blk_data.request_queue_lock);
	184	atomic_set(&device->blk_data.requeue_scheduled, 0);
	185	}
	186
	187	/*
	188	* Tape request queue function. Called from ll_rw_blk.c
	189	*/
	190	static void
165125e1	191	tapeblock_request_fn(struct request_queue *queue)
1da177e4 LT	192	{
	193	struct tape_device *device;
	194
	195	device = (struct tape_device *) queue->queuedata;
	196	DBF_LH(6, "tapeblock_request_fn(device=%p)\n", device);
3a8dc893	197	BUG_ON(device == NULL);
1da177e4 LT	198	tapeblock_trigger_requeue(device);
	199	}
	200
	201	/*
	202	* This function is called for every new tapedevice
	203	*/
	204	int
	205	tapeblock_setup_device(struct tape_device * device)
	206	{
	207	struct tape_blk_data * blkdat;
	208	struct gendisk * disk;
	209	int rc;
	210
	211	blkdat = &device->blk_data;
c1637532	212	blkdat->device = device;
1da177e4 LT	213	spin_lock_init(&blkdat->request_queue_lock);
	214	atomic_set(&blkdat->requeue_scheduled, 0);
	215
	216	blkdat->request_queue = blk_init_queue(
	217	tapeblock_request_fn,
	218	&blkdat->request_queue_lock
	219	);
	220	if (!blkdat->request_queue)
	221	return -ENOMEM;
	222
	223	elevator_exit(blkdat->request_queue->elevator);
	224	rc = elevator_init(blkdat->request_queue, "noop");
	225	if (rc)
	226	goto cleanup_queue;
	227
	228	blk_queue_hardsect_size(blkdat->request_queue, TAPEBLOCK_HSEC_SIZE);
	229	blk_queue_max_sectors(blkdat->request_queue, TAPEBLOCK_MAX_SEC);
	230	blk_queue_max_phys_segments(blkdat->request_queue, -1L);
	231	blk_queue_max_hw_segments(blkdat->request_queue, -1L);
	232	blk_queue_max_segment_size(blkdat->request_queue, -1L);
	233	blk_queue_segment_boundary(blkdat->request_queue, -1L);
	234
	235	disk = alloc_disk(1);
	236	if (!disk) {
	237	rc = -ENOMEM;
	238	goto cleanup_queue;
	239	}
	240
	241	disk->major = tapeblock_major;
	242	disk->first_minor = device->first_minor;
	243	disk->fops = &tapeblock_fops;
	244	disk->private_data = tape_get_device_reference(device);
	245	disk->queue = blkdat->request_queue;
	246	set_capacity(disk, 0);
	247	sprintf(disk->disk_name, "btibm%d",
	248	device->first_minor / TAPE_MINORS_PER_DEV);
	249
	250	blkdat->disk = disk;
	251	blkdat->medium_changed = 1;
	252	blkdat->request_queue->queuedata = tape_get_device_reference(device);
	253
	254	add_disk(disk);
	255
c1637532 MS	256	tape_get_device_reference(device);
c1637532 MS	257	INIT_WORK(&blkdat->requeue_task, tapeblock_requeue);
1da177e4 LT	258
	259	return 0;
	260
	261	cleanup_queue:
	262	blk_cleanup_queue(blkdat->request_queue);
	263	blkdat->request_queue = NULL;
	264
	265	return rc;
	266	}
	267
	268	void
	269	tapeblock_cleanup_device(struct tape_device *device)
	270	{
	271	flush_scheduled_work();
c1637532	272	tape_put_device(device);
1da177e4 LT	273
1da177e4 LT	274	if (!device->blk_data.disk) {
1da177e4 LT	275	goto cleanup_queue;
	276	}
	277
	278	del_gendisk(device->blk_data.disk);
	279	device->blk_data.disk->private_data =
	280	tape_put_device(device->blk_data.disk->private_data);
	281	put_disk(device->blk_data.disk);
	282
	283	device->blk_data.disk = NULL;
	284	cleanup_queue:
	285	device->blk_data.request_queue->queuedata = tape_put_device(device);
	286
	287	blk_cleanup_queue(device->blk_data.request_queue);
	288	device->blk_data.request_queue = NULL;
	289	}
	290
	291	/*
	292	* Detect number of blocks of the tape.
	293	* FIXME: can we extent this to detect the blocks size as well ?
	294	*/
	295	static int
	296	tapeblock_revalidate_disk(struct gendisk *disk)
	297	{
	298	struct tape_device * device;
	299	unsigned int nr_of_blks;
	300	int rc;
	301
	302	device = (struct tape_device *) disk->private_data;
3a8dc893	303	BUG_ON(!device);
1da177e4 LT	304
	305	if (!device->blk_data.medium_changed)
	306	return 0;
	307
ab640db0 CO	308	dev_info(&device->cdev->dev, "Determining the size of the recorded "
ab640db0 CO	309	"area...\n");
1da177e4 LT	310	rc = tape_mtop(device, MTFSFM, 1);
	311	if (rc)
	312	return rc;
	313
	314	rc = tape_mtop(device, MTTELL, 1);
	315	if (rc < 0)
	316	return rc;
	317
	318	DBF_LH(3, "Image file ends at %d\n", rc);
	319	nr_of_blks = rc;
	320
	321	/* This will fail for the first file. Catch the error by checking the
	322	* position. */
	323	tape_mtop(device, MTBSF, 1);
	324
	325	rc = tape_mtop(device, MTTELL, 1);
	326	if (rc < 0)
	327	return rc;
	328
	329	if (rc > nr_of_blks)
	330	return -EINVAL;
	331
	332	DBF_LH(3, "Image file starts at %d\n", rc);
	333	device->bof = rc;
	334	nr_of_blks -= rc;
	335
ab640db0 CO	336	dev_info(&device->cdev->dev, "The size of the recorded area is %i "
ab640db0 CO	337	"blocks\n", nr_of_blks);
1da177e4 LT	338	set_capacity(device->blk_data.disk,
	339	nr_of_blks*(TAPEBLOCK_HSEC_SIZE/512));
	340
	341	device->blk_data.block_position = 0;
	342	device->blk_data.medium_changed = 0;
	343	return 0;
	344	}
	345
	346	static int
	347	tapeblock_medium_changed(struct gendisk *disk)
	348	{
	349	struct tape_device *device;
	350
	351	device = (struct tape_device *) disk->private_data;
	352	DBF_LH(6, "tapeblock_medium_changed(%p) = %d\n",
	353	device, device->blk_data.medium_changed);
	354
	355	return device->blk_data.medium_changed;
	356	}
	357
	358	/*
	359	* Block frontend tape device open function.
	360	*/
	361	static int
4e999af9	362	tapeblock_open(struct block_device *bdev, fmode_t mode)
1da177e4	363	{
4e999af9	364	struct gendisk * disk = bdev->bd_disk;
1da177e4 LT	365	struct tape_device * device;
	366	int rc;
	367
1da177e4 LT	368	device = tape_get_device_reference(disk->private_data);
	369
	370	if (device->required_tapemarks) {
	371	DBF_EVENT(2, "TBLOCK: missing tapemarks\n");
ab640db0 CO	372	dev_warn(&device->cdev->dev, "Opening the tape failed because"
ab640db0 CO	373	" of missing end-of-file marks\n");
1da177e4 LT	374	rc = -EPERM;
	375	goto put_device;
	376	}
	377
	378	rc = tape_open(device);
	379	if (rc)
	380	goto put_device;
	381
	382	rc = tapeblock_revalidate_disk(disk);
	383	if (rc)
	384	goto release;
	385
	386	/*
	387	* Note: The reference to <device> is hold until the release function
	388	* is called.
	389	*/
	390	tape_state_set(device, TS_BLKUSE);
	391	return 0;
	392
	393	release:
	394	tape_release(device);
	395	put_device:
	396	tape_put_device(device);
	397	return rc;
	398	}
	399
	400	/*
	401	* Block frontend tape device release function.
	402	*
	403	* Note: One reference to the tape device was made by the open function. So
	404	* we just get the pointer here and release the reference.
	405	*/
	406	static int
4e999af9	407	tapeblock_release(struct gendisk *disk, fmode_t mode)
1da177e4	408	{
1da177e4 LT	409	struct tape_device *device = disk->private_data;
	410
	411	tape_state_set(device, TS_IN_USE);
	412	tape_release(device);
	413	tape_put_device(device);
	414
	415	return 0;
	416	}
	417
	418	/*
	419	* Support of some generic block device IOCTLs.
	420	*/
	421	static int
	422	tapeblock_ioctl(
4e999af9 AV	423	struct block_device * bdev,
4e999af9 AV	424	fmode_t mode,
1da177e4 LT	425	unsigned int command,
	426	unsigned long arg
	427	) {
	428	int rc;
	429	int minor;
4e999af9	430	struct gendisk *disk = bdev->bd_disk;
f976069a	431	struct tape_device *device;
1da177e4 LT	432
1da177e4 LT	433	rc = 0;
3a8dc893	434	BUG_ON(!disk);
1da177e4	435	device = disk->private_data;
3a8dc893	436	BUG_ON(!device);
4e999af9	437	minor = MINOR(bdev->bd_dev);
1da177e4 LT	438
	439	DBF_LH(6, "tapeblock_ioctl(0x%0x)\n", command);
	440	DBF_LH(6, "device = %d:%d\n", tapeblock_major, minor);
	441
	442	switch (command) {
	443	/* Refuse some IOCTL calls without complaining (mount). */
	444	case 0x5310: /* CDROMMULTISESSION */
	445	rc = -EINVAL;
	446	break;
	447	default:
1da177e4 LT	448	rc = -EINVAL;
	449	}
	450
	451	return rc;
	452	}
	453
	454	/*
	455	* Initialize block device frontend.
	456	*/
	457	int
	458	tapeblock_init(void)
	459	{
	460	int rc;
	461
	462	/* Register the tape major number to the kernel */
	463	rc = register_blkdev(tapeblock_major, "tBLK");
	464	if (rc < 0)
	465	return rc;
	466
	467	if (tapeblock_major == 0)
	468	tapeblock_major = rc;
1da177e4 LT	469	return 0;
	470	}
	471
	472	/*
	473	* Deregister major for block device frontend
	474	*/
	475	void
	476	tapeblock_exit(void)
	477	{
	478	unregister_blkdev(tapeblock_major, "tBLK");
	479	}