[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"
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt

#include <linux/fs.h>
#include <linux/module.h>
#include <linux/blkdev.h>
#include <linux/smp_lock.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_medium_changed(struct gendisk *);
static int tapeblock_revalidate_disk(struct gendisk *);

static const struct block_device_operations tapeblock_fops = {
	.owner		 = THIS_MODULE,
	.open		 = tapeblock_open,
	.release	 = tapeblock_release,
	.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) ||
	    blk_peek_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) &&
		blk_peek_request(queue) &&
		nr_queued < TAPEBLOCK_MIN_REQUEUE
	) {
		req = blk_fetch_request(queue);
		if (rq_data_dir(req) == WRITE) {
			DBF_EVENT(1, "TBLOCK: Rejecting write request\n");
			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;
		}
		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;

	rc = elevator_change(blkdat->request_queue, "noop");
	if (rc)
		goto cleanup_queue;

	blk_queue_logical_block_size(blkdat->request_queue, TAPEBLOCK_HSEC_SIZE);
	blk_queue_max_hw_sectors(blkdat->request_queue, TAPEBLOCK_MAX_SEC);
	blk_queue_max_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(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(device);

	add_disk(disk);

	tape_get_device(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 = NULL;
	tape_put_device(device);
	put_disk(device->blk_data.disk);

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

	rc = tape_mtop(device, MTFSFM, 1);
	if (rc)
		return rc;

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

	pr_info("%s: Determining the size of the recorded area...\n",
		dev_name(&device->cdev->dev));
	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;

	pr_info("%s: The size of the recorded area is %i blocks\n",
		dev_name(&device->cdev->dev), 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;

	lock_kernel();
	device = tape_get_device(disk->private_data);

	if (device->required_tapemarks) {
		DBF_EVENT(2, "TBLOCK: missing tapemarks\n");
		pr_warning("%s: Opening the tape failed because of missing "
			   "end-of-file marks\n", dev_name(&device->cdev->dev));
		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);
	unlock_kernel();
	return 0;

release:
	tape_release(device);
 put_device:
	tape_put_device(device);
	unlock_kernel();
	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;
 
	lock_kernel();
	tape_state_set(device, TS_IN_USE);
	tape_release(device);
	tape_put_device(device);
	unlock_kernel();

	return 0;
}

/*
 * 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	13	#define KMSG_COMPONENT "tape"
bb509912	14	#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
ab640db0	15
1da177e4	16	#include <linux/fs.h>
1da177e4 LT	17	#include <linux/module.h>
1da177e4 LT	18	#include <linux/blkdev.h>
6e9624b8	19	#include <linux/smp_lock.h>
1da177e4 LT	20	#include <linux/interrupt.h>
1da177e4 LT	21	#include <linux/buffer_head.h>
c1637532	22	#include <linux/kernel.h>
1da177e4 LT	23
	24	#include <asm/debug.h>
	25
	26	#define TAPE_DBF_AREA tape_core_dbf
	27
	28	#include "tape.h"
	29
1da177e4 LT	30	#define TAPEBLOCK_MAX_SEC 100
	31	#define TAPEBLOCK_MIN_REQUEUE 3
	32
	33	/*
	34	* 2003/11/25 Stefan Bader <shbader@de.ibm.com>
	35	*
	36	* In 2.5/2.6 the block device request function is very likely to be called
	37	* with disabled interrupts (e.g. generic_unplug_device). So the driver can't
	38	* just call any function that tries to allocate CCW requests from that con-
	39	* text since it might sleep. There are two choices to work around this:
	40	* a) do not allocate with kmalloc but use its own memory pool
	41	* b) take requests from the queue outside that context, knowing that
	42	* allocation might sleep
	43	*/
	44
	45	/*
	46	* file operation structure for tape block frontend
	47	*/
4e999af9 AV	48	static int tapeblock_open(struct block_device *, fmode_t);
4e999af9 AV	49	static int tapeblock_release(struct gendisk *, fmode_t);
1da177e4 LT	50	static int tapeblock_medium_changed(struct gendisk *);
	51	static int tapeblock_revalidate_disk(struct gendisk *);
	52
83d5cde4	53	static const struct block_device_operations tapeblock_fops = {
1da177e4	54	.owner = THIS_MODULE,
4e999af9 AV	55	.open = tapeblock_open,
4e999af9 AV	56	.release = tapeblock_release,
1da177e4 LT	57	.media_changed = tapeblock_medium_changed,
	58	.revalidate_disk = tapeblock_revalidate_disk,
	59	};
	60
	61	static int tapeblock_major = 0;
	62
	63	static void
	64	tapeblock_trigger_requeue(struct tape_device *device)
	65	{
	66	/* Protect against rescheduling. */
973bd993	67	if (atomic_cmpxchg(&device->blk_data.requeue_scheduled, 0, 1) != 0)
1da177e4 LT	68	return;
	69	schedule_work(&device->blk_data.requeue_task);
	70	}
	71
	72	/*
	73	* Post finished request.
	74	*/
1da177e4 LT	75	static void
	76	__tapeblock_end_request(struct tape_request ccw_req, void data)
	77	{
	78	struct tape_device *device;
	79	struct request *req;
	80
	81	DBF_LH(6, "__tapeblock_end_request()\n");
	82
	83	device = ccw_req->device;
	84	req = (struct request *) data;
40cbbb78	85	blk_end_request_all(req, (ccw_req->rc == 0) ? 0 : -EIO);
1da177e4 LT	86	if (ccw_req->rc == 0)
	87	/* Update position. */
	88	device->blk_data.block_position =
83096ebf	89	(blk_rq_pos(req) + blk_rq_sectors(req)) >> TAPEBLOCK_HSEC_S2B;
1da177e4 LT	90	else
	91	/* We lost the position information due to an error. */
	92	device->blk_data.block_position = -1;
	93	device->discipline->free_bread(ccw_req);
	94	if (!list_empty(&device->req_queue) \|\|
9934c8c0	95	blk_peek_request(device->blk_data.request_queue))
1da177e4 LT	96	tapeblock_trigger_requeue(device);
	97	}
	98
	99	/*
	100	* Feed the tape device CCW queue with requests supplied in a list.
	101	*/
4d284cac	102	static int
1da177e4 LT	103	tapeblock_start_request(struct tape_device device, struct request req)
	104	{
	105	struct tape_request * ccw_req;
	106	int rc;
	107
	108	DBF_LH(6, "tapeblock_start_request(%p, %p)\n", device, req);
	109
	110	ccw_req = device->discipline->bread(device, req);
	111	if (IS_ERR(ccw_req)) {
	112	DBF_EVENT(1, "TBLOCK: bread failed\n");
40cbbb78	113	blk_end_request_all(req, -EIO);
1da177e4 LT	114	return PTR_ERR(ccw_req);
	115	}
	116	ccw_req->callback = __tapeblock_end_request;
	117	ccw_req->callback_data = (void *) req;
	118	ccw_req->retries = TAPEBLOCK_RETRIES;
	119
	120	rc = tape_do_io_async(device, ccw_req);
	121	if (rc) {
	122	/*
	123	* Start/enqueueing failed. No retries in
	124	* this case.
	125	*/
40cbbb78	126	blk_end_request_all(req, -EIO);
1da177e4 LT	127	device->discipline->free_bread(ccw_req);
	128	}
	129
	130	return rc;
	131	}
	132
	133	/*
	134	* Move requests from the block device request queue to the tape device ccw
	135	* queue.
	136	*/
	137	static void
c1637532 MS	138	tapeblock_requeue(struct work_struct *work) {
c1637532 MS	139	struct tape_blk_data * blkdat;
1da177e4	140	struct tape_device * device;
165125e1	141	struct request_queue * queue;
1da177e4 LT	142	int nr_queued;
	143	struct request * req;
	144	struct list_head * l;
	145	int rc;
	146
c1637532 MS	147	blkdat = container_of(work, struct tape_blk_data, requeue_task);
c1637532 MS	148	device = blkdat->device;
1da177e4 LT	149	if (!device)
	150	return;
	151
	152	spin_lock_irq(get_ccwdev_lock(device->cdev));
	153	queue = device->blk_data.request_queue;
	154
	155	/* Count number of requests on ccw queue. */
	156	nr_queued = 0;
	157	list_for_each(l, &device->req_queue)
	158	nr_queued++;
	159	spin_unlock(get_ccwdev_lock(device->cdev));
	160
7a4a1ccd	161	spin_lock_irq(&device->blk_data.request_queue_lock);
1da177e4 LT	162	while (
1da177e4 LT	163	!blk_queue_plugged(queue) &&
03cadd36	164	blk_peek_request(queue) &&
1da177e4 LT	165	nr_queued < TAPEBLOCK_MIN_REQUEUE
1da177e4 LT	166	) {
03cadd36	167	req = blk_fetch_request(queue);
1da177e4 LT	168	if (rq_data_dir(req) == WRITE) {
1da177e4 LT	169	DBF_EVENT(1, "TBLOCK: Rejecting write request\n");
7a4a1ccd	170	spin_unlock_irq(&device->blk_data.request_queue_lock);
40cbbb78	171	blk_end_request_all(req, -EIO);
7a4a1ccd	172	spin_lock_irq(&device->blk_data.request_queue_lock);
1da177e4 LT	173	continue;
1da177e4 LT	174	}
f71ad62a	175	nr_queued++;
1da177e4 LT	176	spin_unlock_irq(&device->blk_data.request_queue_lock);
	177	rc = tapeblock_start_request(device, req);
	178	spin_lock_irq(&device->blk_data.request_queue_lock);
1da177e4 LT	179	}
	180	spin_unlock_irq(&device->blk_data.request_queue_lock);
	181	atomic_set(&device->blk_data.requeue_scheduled, 0);
	182	}
	183
	184	/*
	185	* Tape request queue function. Called from ll_rw_blk.c
	186	*/
	187	static void
165125e1	188	tapeblock_request_fn(struct request_queue *queue)
1da177e4 LT	189	{
	190	struct tape_device *device;
	191
	192	device = (struct tape_device *) queue->queuedata;
	193	DBF_LH(6, "tapeblock_request_fn(device=%p)\n", device);
3a8dc893	194	BUG_ON(device == NULL);
1da177e4 LT	195	tapeblock_trigger_requeue(device);
	196	}
	197
	198	/*
	199	* This function is called for every new tapedevice
	200	*/
	201	int
	202	tapeblock_setup_device(struct tape_device * device)
	203	{
	204	struct tape_blk_data * blkdat;
	205	struct gendisk * disk;
	206	int rc;
	207
	208	blkdat = &device->blk_data;
c1637532	209	blkdat->device = device;
1da177e4 LT	210	spin_lock_init(&blkdat->request_queue_lock);
	211	atomic_set(&blkdat->requeue_scheduled, 0);
	212
	213	blkdat->request_queue = blk_init_queue(
	214	tapeblock_request_fn,
	215	&blkdat->request_queue_lock
	216	);
	217	if (!blkdat->request_queue)
	218	return -ENOMEM;
	219
52cc2eef	220	rc = elevator_change(blkdat->request_queue, "noop");
1da177e4 LT	221	if (rc)
	222	goto cleanup_queue;
	223
e1defc4f	224	blk_queue_logical_block_size(blkdat->request_queue, TAPEBLOCK_HSEC_SIZE);
086fa5ff	225	blk_queue_max_hw_sectors(blkdat->request_queue, TAPEBLOCK_MAX_SEC);
8a78362c	226	blk_queue_max_segments(blkdat->request_queue, -1L);
1da177e4 LT	227	blk_queue_max_segment_size(blkdat->request_queue, -1L);
	228	blk_queue_segment_boundary(blkdat->request_queue, -1L);
	229
	230	disk = alloc_disk(1);
	231	if (!disk) {
	232	rc = -ENOMEM;
	233	goto cleanup_queue;
	234	}
	235
	236	disk->major = tapeblock_major;
	237	disk->first_minor = device->first_minor;
	238	disk->fops = &tapeblock_fops;
8fd138c3	239	disk->private_data = tape_get_device(device);
1da177e4 LT	240	disk->queue = blkdat->request_queue;
	241	set_capacity(disk, 0);
	242	sprintf(disk->disk_name, "btibm%d",
	243	device->first_minor / TAPE_MINORS_PER_DEV);
	244
	245	blkdat->disk = disk;
	246	blkdat->medium_changed = 1;
8fd138c3	247	blkdat->request_queue->queuedata = tape_get_device(device);
1da177e4 LT	248
	249	add_disk(disk);
	250
8fd138c3	251	tape_get_device(device);
c1637532	252	INIT_WORK(&blkdat->requeue_task, tapeblock_requeue);
1da177e4 LT	253
	254	return 0;
	255
	256	cleanup_queue:
	257	blk_cleanup_queue(blkdat->request_queue);
	258	blkdat->request_queue = NULL;
	259
	260	return rc;
	261	}
	262
	263	void
	264	tapeblock_cleanup_device(struct tape_device *device)
	265	{
	266	flush_scheduled_work();
c1637532	267	tape_put_device(device);
1da177e4 LT	268
1da177e4 LT	269	if (!device->blk_data.disk) {
1da177e4 LT	270	goto cleanup_queue;
	271	}
	272
	273	del_gendisk(device->blk_data.disk);
8fd138c3 MS	274	device->blk_data.disk->private_data = NULL;
8fd138c3 MS	275	tape_put_device(device);
1da177e4 LT	276	put_disk(device->blk_data.disk);
	277
	278	device->blk_data.disk = NULL;
	279	cleanup_queue:
8fd138c3 MS	280	device->blk_data.request_queue->queuedata = NULL;
8fd138c3 MS	281	tape_put_device(device);
1da177e4 LT	282
	283	blk_cleanup_queue(device->blk_data.request_queue);
	284	device->blk_data.request_queue = NULL;
	285	}
	286
	287	/*
	288	* Detect number of blocks of the tape.
	289	* FIXME: can we extent this to detect the blocks size as well ?
	290	*/
	291	static int
	292	tapeblock_revalidate_disk(struct gendisk *disk)
	293	{
	294	struct tape_device * device;
	295	unsigned int nr_of_blks;
	296	int rc;
	297
	298	device = (struct tape_device *) disk->private_data;
3a8dc893	299	BUG_ON(!device);
1da177e4 LT	300
	301	if (!device->blk_data.medium_changed)
	302	return 0;
	303
1da177e4 LT	304	rc = tape_mtop(device, MTFSFM, 1);
	305	if (rc)
	306	return rc;
	307
	308	rc = tape_mtop(device, MTTELL, 1);
	309	if (rc < 0)
	310	return rc;
	311
59e36927 MH	312	pr_info("%s: Determining the size of the recorded area...\n",
59e36927 MH	313	dev_name(&device->cdev->dev));
1da177e4 LT	314	DBF_LH(3, "Image file ends at %d\n", rc);
	315	nr_of_blks = rc;
	316
	317	/* This will fail for the first file. Catch the error by checking the
	318	* position. */
	319	tape_mtop(device, MTBSF, 1);
	320
	321	rc = tape_mtop(device, MTTELL, 1);
	322	if (rc < 0)
	323	return rc;
	324
	325	if (rc > nr_of_blks)
	326	return -EINVAL;
	327
	328	DBF_LH(3, "Image file starts at %d\n", rc);
	329	device->bof = rc;
	330	nr_of_blks -= rc;
	331
59e36927 MH	332	pr_info("%s: The size of the recorded area is %i blocks\n",
59e36927 MH	333	dev_name(&device->cdev->dev), nr_of_blks);
1da177e4 LT	334	set_capacity(device->blk_data.disk,
	335	nr_of_blks*(TAPEBLOCK_HSEC_SIZE/512));
	336
	337	device->blk_data.block_position = 0;
	338	device->blk_data.medium_changed = 0;
	339	return 0;
	340	}
	341
	342	static int
	343	tapeblock_medium_changed(struct gendisk *disk)
	344	{
	345	struct tape_device *device;
	346
	347	device = (struct tape_device *) disk->private_data;
	348	DBF_LH(6, "tapeblock_medium_changed(%p) = %d\n",
	349	device, device->blk_data.medium_changed);
	350
	351	return device->blk_data.medium_changed;
	352	}
	353
	354	/*
	355	* Block frontend tape device open function.
	356	*/
	357	static int
4e999af9	358	tapeblock_open(struct block_device *bdev, fmode_t mode)
1da177e4	359	{
4e999af9	360	struct gendisk * disk = bdev->bd_disk;
1da177e4 LT	361	struct tape_device * device;
	362	int rc;
	363
6e9624b8	364	lock_kernel();
8fd138c3	365	device = tape_get_device(disk->private_data);
1da177e4 LT	366
	367	if (device->required_tapemarks) {
	368	DBF_EVENT(2, "TBLOCK: missing tapemarks\n");
59e36927 MH	369	pr_warning("%s: Opening the tape failed because of missing "
59e36927 MH	370	"end-of-file marks\n", dev_name(&device->cdev->dev));
1da177e4 LT	371	rc = -EPERM;
	372	goto put_device;
	373	}
	374
	375	rc = tape_open(device);
	376	if (rc)
	377	goto put_device;
	378
	379	rc = tapeblock_revalidate_disk(disk);
	380	if (rc)
	381	goto release;
	382
	383	/*
	384	* Note: The reference to <device> is hold until the release function
	385	* is called.
	386	*/
	387	tape_state_set(device, TS_BLKUSE);
6e9624b8	388	unlock_kernel();
1da177e4 LT	389	return 0;
	390
	391	release:
	392	tape_release(device);
	393	put_device:
	394	tape_put_device(device);
6e9624b8	395	unlock_kernel();
1da177e4 LT	396	return rc;
	397	}
	398
	399	/*
	400	* Block frontend tape device release function.
	401	*
	402	* Note: One reference to the tape device was made by the open function. So
	403	* we just get the pointer here and release the reference.
	404	*/
	405	static int
4e999af9	406	tapeblock_release(struct gendisk *disk, fmode_t mode)
1da177e4	407	{
1da177e4	408	struct tape_device *device = disk->private_data;
6e9624b8 AB	409
6e9624b8 AB	410	lock_kernel();
1da177e4 LT	411	tape_state_set(device, TS_IN_USE);
	412	tape_release(device);
	413	tape_put_device(device);
6e9624b8	414	unlock_kernel();
1da177e4 LT	415
	416	return 0;
	417	}
	418
1da177e4 LT	419	/*
	420	* Initialize block device frontend.
	421	*/
	422	int
	423	tapeblock_init(void)
	424	{
	425	int rc;
	426
	427	/* Register the tape major number to the kernel */
	428	rc = register_blkdev(tapeblock_major, "tBLK");
	429	if (rc < 0)
	430	return rc;
	431
	432	if (tapeblock_major == 0)
	433	tapeblock_major = rc;
1da177e4 LT	434	return 0;
	435	}
	436
	437	/*
	438	* Deregister major for block device frontend
	439	*/
	440	void
	441	tapeblock_exit(void)
	442	{
	443	unregister_blkdev(tapeblock_major, "tBLK");
	444	}