[mirror_ubuntu-bionic-kernel.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 inode *, struct file *);
static int tapeblock_release(struct inode *, struct file *);
static int tapeblock_ioctl(struct inode *, struct file *, 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,
	.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 uptodate)
{
	if (end_that_request_first(req, uptodate, req->hard_nr_sectors))
		BUG();
	end_that_request_last(req, uptodate);
}

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);
	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, 0);
		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, 0);
		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(&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);
			tapeblock_end_request(req, 0);
			continue;
		}
		spin_unlock_irq(&device->blk_data.request_queue_lock);
		rc = tapeblock_start_request(device, req);
		spin_lock_irq(&device->blk_data.request_queue_lock);
		blkdev_dequeue_request(req);
		nr_queued++;
	}
	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",
			device->cdev->dev.bus_id);
		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 inode *inode, struct file *filp)
{
	struct gendisk *	disk;
	struct tape_device *	device;
	int			rc;

	disk   = inode->i_bdev->bd_disk;
	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 inode *inode, struct file *filp)
{
	struct gendisk *disk = inode->i_bdev->bd_disk;
	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 inode *		inode,
	struct file *		file,
	unsigned int		command,
	unsigned long		arg
) {
	int rc;
	int minor;
	struct gendisk *disk;
	struct tape_device *device;

	rc     = 0;
	disk   = inode->i_bdev->bd_disk;
	BUG_ON(!disk);
	device = disk->private_data;
	BUG_ON(!device);
	minor  = iminor(inode);

	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	*/
	46	static int tapeblock_open(struct inode , struct file );
	47	static int tapeblock_release(struct inode , struct file );
	48	static int tapeblock_ioctl(struct inode , struct file , unsigned int,
	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,
	55	.open = tapeblock_open,
	56	.release = tapeblock_release,
	57	.ioctl = tapeblock_ioctl,
	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
1da177e4 LT	77	tapeblock_end_request(struct request *req, int uptodate)
	78	{
	79	if (end_that_request_first(req, uptodate, req->hard_nr_sectors))
	80	BUG();
8ffdc655	81	end_that_request_last(req, uptodate);
1da177e4 LT	82	}
	83
	84	static void
	85	__tapeblock_end_request(struct tape_request ccw_req, void data)
	86	{
	87	struct tape_device *device;
	88	struct request *req;
	89
	90	DBF_LH(6, "__tapeblock_end_request()\n");
	91
	92	device = ccw_req->device;
	93	req = (struct request *) data;
	94	tapeblock_end_request(req, ccw_req->rc == 0);
	95	if (ccw_req->rc == 0)
	96	/* Update position. */
	97	device->blk_data.block_position =
	98	(req->sector + req->nr_sectors) >> TAPEBLOCK_HSEC_S2B;
	99	else
	100	/* We lost the position information due to an error. */
	101	device->blk_data.block_position = -1;
	102	device->discipline->free_bread(ccw_req);
	103	if (!list_empty(&device->req_queue) \|\|
	104	elv_next_request(device->blk_data.request_queue))
	105	tapeblock_trigger_requeue(device);
	106	}
	107
	108	/*
	109	* Feed the tape device CCW queue with requests supplied in a list.
	110	*/
4d284cac	111	static int
1da177e4 LT	112	tapeblock_start_request(struct tape_device device, struct request req)
	113	{
	114	struct tape_request * ccw_req;
	115	int rc;
	116
	117	DBF_LH(6, "tapeblock_start_request(%p, %p)\n", device, req);
	118
	119	ccw_req = device->discipline->bread(device, req);
	120	if (IS_ERR(ccw_req)) {
	121	DBF_EVENT(1, "TBLOCK: bread failed\n");
	122	tapeblock_end_request(req, 0);
	123	return PTR_ERR(ccw_req);
	124	}
	125	ccw_req->callback = __tapeblock_end_request;
	126	ccw_req->callback_data = (void *) req;
	127	ccw_req->retries = TAPEBLOCK_RETRIES;
	128
	129	rc = tape_do_io_async(device, ccw_req);
	130	if (rc) {
	131	/*
	132	* Start/enqueueing failed. No retries in
	133	* this case.
	134	*/
	135	tapeblock_end_request(req, 0);
	136	device->discipline->free_bread(ccw_req);
	137	}
	138
	139	return rc;
	140	}
	141
	142	/*
	143	* Move requests from the block device request queue to the tape device ccw
	144	* queue.
	145	*/
	146	static void
c1637532 MS	147	tapeblock_requeue(struct work_struct *work) {
c1637532 MS	148	struct tape_blk_data * blkdat;
1da177e4	149	struct tape_device * device;
165125e1	150	struct request_queue * queue;
1da177e4 LT	151	int nr_queued;
	152	struct request * req;
	153	struct list_head * l;
	154	int rc;
	155
c1637532 MS	156	blkdat = container_of(work, struct tape_blk_data, requeue_task);
c1637532 MS	157	device = blkdat->device;
1da177e4 LT	158	if (!device)
	159	return;
	160
	161	spin_lock_irq(get_ccwdev_lock(device->cdev));
	162	queue = device->blk_data.request_queue;
	163
	164	/* Count number of requests on ccw queue. */
	165	nr_queued = 0;
	166	list_for_each(l, &device->req_queue)
	167	nr_queued++;
	168	spin_unlock(get_ccwdev_lock(device->cdev));
	169
	170	spin_lock(&device->blk_data.request_queue_lock);
	171	while (
	172	!blk_queue_plugged(queue) &&
	173	elv_next_request(queue) &&
	174	nr_queued < TAPEBLOCK_MIN_REQUEUE
	175	) {
	176	req = elv_next_request(queue);
	177	if (rq_data_dir(req) == WRITE) {
	178	DBF_EVENT(1, "TBLOCK: Rejecting write request\n");
	179	blkdev_dequeue_request(req);
	180	tapeblock_end_request(req, 0);
	181	continue;
	182	}
	183	spin_unlock_irq(&device->blk_data.request_queue_lock);
	184	rc = tapeblock_start_request(device, req);
	185	spin_lock_irq(&device->blk_data.request_queue_lock);
	186	blkdev_dequeue_request(req);
	187	nr_queued++;
	188	}
	189	spin_unlock_irq(&device->blk_data.request_queue_lock);
	190	atomic_set(&device->blk_data.requeue_scheduled, 0);
	191	}
	192
	193	/*
	194	* Tape request queue function. Called from ll_rw_blk.c
	195	*/
	196	static void
165125e1	197	tapeblock_request_fn(struct request_queue *queue)
1da177e4 LT	198	{
	199	struct tape_device *device;
	200
	201	device = (struct tape_device *) queue->queuedata;
	202	DBF_LH(6, "tapeblock_request_fn(device=%p)\n", device);
3a8dc893	203	BUG_ON(device == NULL);
1da177e4 LT	204	tapeblock_trigger_requeue(device);
	205	}
	206
	207	/*
	208	* This function is called for every new tapedevice
	209	*/
	210	int
	211	tapeblock_setup_device(struct tape_device * device)
	212	{
	213	struct tape_blk_data * blkdat;
	214	struct gendisk * disk;
	215	int rc;
	216
	217	blkdat = &device->blk_data;
c1637532	218	blkdat->device = device;
1da177e4 LT	219	spin_lock_init(&blkdat->request_queue_lock);
	220	atomic_set(&blkdat->requeue_scheduled, 0);
	221
	222	blkdat->request_queue = blk_init_queue(
	223	tapeblock_request_fn,
	224	&blkdat->request_queue_lock
	225	);
	226	if (!blkdat->request_queue)
	227	return -ENOMEM;
	228
	229	elevator_exit(blkdat->request_queue->elevator);
	230	rc = elevator_init(blkdat->request_queue, "noop");
	231	if (rc)
	232	goto cleanup_queue;
	233
	234	blk_queue_hardsect_size(blkdat->request_queue, TAPEBLOCK_HSEC_SIZE);
	235	blk_queue_max_sectors(blkdat->request_queue, TAPEBLOCK_MAX_SEC);
	236	blk_queue_max_phys_segments(blkdat->request_queue, -1L);
	237	blk_queue_max_hw_segments(blkdat->request_queue, -1L);
	238	blk_queue_max_segment_size(blkdat->request_queue, -1L);
	239	blk_queue_segment_boundary(blkdat->request_queue, -1L);
	240
	241	disk = alloc_disk(1);
	242	if (!disk) {
	243	rc = -ENOMEM;
	244	goto cleanup_queue;
	245	}
	246
	247	disk->major = tapeblock_major;
	248	disk->first_minor = device->first_minor;
	249	disk->fops = &tapeblock_fops;
	250	disk->private_data = tape_get_device_reference(device);
	251	disk->queue = blkdat->request_queue;
	252	set_capacity(disk, 0);
	253	sprintf(disk->disk_name, "btibm%d",
	254	device->first_minor / TAPE_MINORS_PER_DEV);
	255
	256	blkdat->disk = disk;
	257	blkdat->medium_changed = 1;
	258	blkdat->request_queue->queuedata = tape_get_device_reference(device);
	259
	260	add_disk(disk);
	261
c1637532 MS	262	tape_get_device_reference(device);
c1637532 MS	263	INIT_WORK(&blkdat->requeue_task, tapeblock_requeue);
1da177e4 LT	264
	265	return 0;
	266
	267	cleanup_queue:
	268	blk_cleanup_queue(blkdat->request_queue);
	269	blkdat->request_queue = NULL;
	270
	271	return rc;
	272	}
	273
	274	void
	275	tapeblock_cleanup_device(struct tape_device *device)
	276	{
	277	flush_scheduled_work();
c1637532	278	tape_put_device(device);
1da177e4 LT	279
	280	if (!device->blk_data.disk) {
	281	PRINT_ERR("(%s): No gendisk to clean up!\n",
	282	device->cdev->dev.bus_id);
	283	goto cleanup_queue;
	284	}
	285
	286	del_gendisk(device->blk_data.disk);
	287	device->blk_data.disk->private_data =
	288	tape_put_device(device->blk_data.disk->private_data);
	289	put_disk(device->blk_data.disk);
	290
	291	device->blk_data.disk = NULL;
	292	cleanup_queue:
	293	device->blk_data.request_queue->queuedata = tape_put_device(device);
	294
	295	blk_cleanup_queue(device->blk_data.request_queue);
	296	device->blk_data.request_queue = NULL;
	297	}
	298
	299	/*
	300	* Detect number of blocks of the tape.
	301	* FIXME: can we extent this to detect the blocks size as well ?
	302	*/
	303	static int
	304	tapeblock_revalidate_disk(struct gendisk *disk)
	305	{
	306	struct tape_device * device;
	307	unsigned int nr_of_blks;
	308	int rc;
	309
	310	device = (struct tape_device *) disk->private_data;
3a8dc893	311	BUG_ON(!device);
1da177e4 LT	312
	313	if (!device->blk_data.medium_changed)
	314	return 0;
	315
	316	PRINT_INFO("Detecting media size...\n");
	317	rc = tape_mtop(device, MTFSFM, 1);
	318	if (rc)
	319	return rc;
	320
	321	rc = tape_mtop(device, MTTELL, 1);
	322	if (rc < 0)
	323	return rc;
	324
	325	DBF_LH(3, "Image file ends at %d\n", rc);
	326	nr_of_blks = rc;
	327
	328	/* This will fail for the first file. Catch the error by checking the
	329	* position. */
	330	tape_mtop(device, MTBSF, 1);
	331
	332	rc = tape_mtop(device, MTTELL, 1);
	333	if (rc < 0)
	334	return rc;
	335
	336	if (rc > nr_of_blks)
	337	return -EINVAL;
	338
	339	DBF_LH(3, "Image file starts at %d\n", rc);
	340	device->bof = rc;
	341	nr_of_blks -= rc;
	342
	343	PRINT_INFO("Found %i blocks on media\n", nr_of_blks);
	344	set_capacity(device->blk_data.disk,
	345	nr_of_blks*(TAPEBLOCK_HSEC_SIZE/512));
	346
	347	device->blk_data.block_position = 0;
	348	device->blk_data.medium_changed = 0;
	349	return 0;
	350	}
	351
	352	static int
	353	tapeblock_medium_changed(struct gendisk *disk)
	354	{
	355	struct tape_device *device;
	356
	357	device = (struct tape_device *) disk->private_data;
	358	DBF_LH(6, "tapeblock_medium_changed(%p) = %d\n",
	359	device, device->blk_data.medium_changed);
	360
	361	return device->blk_data.medium_changed;
	362	}
	363
	364	/*
	365	* Block frontend tape device open function.
	366	*/
	367	static int
	368	tapeblock_open(struct inode inode, struct file filp)
	369	{
	370	struct gendisk * disk;
	371	struct tape_device * device;
	372	int rc;
	373
	374	disk = inode->i_bdev->bd_disk;
	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
414	tapeblock_release(struct inode inode, struct file filp)
415	{
416	struct gendisk *disk = inode->i_bdev->bd_disk;
417	struct tape_device *device = disk->private_data;
418
419	tape_state_set(device, TS_IN_USE);
420	tape_release(device);
421	tape_put_device(device);
422
423	return 0;
424	}
425
426	/*
427	* Support of some generic block device IOCTLs.
428	*/
429	static int
430	tapeblock_ioctl(
431	struct inode * inode,
432	struct file * file,
433	unsigned int command,
434	unsigned long arg
435	) {
436	int rc;
437	int minor;
f976069a PO	438	struct gendisk *disk;
f976069a PO	439	struct tape_device *device;
1da177e4 LT	440
	441	rc = 0;
	442	disk = inode->i_bdev->bd_disk;
3a8dc893	443	BUG_ON(!disk);
1da177e4	444	device = disk->private_data;
3a8dc893	445	BUG_ON(!device);
1da177e4 LT	446	minor = iminor(inode);
	447
	448	DBF_LH(6, "tapeblock_ioctl(0x%0x)\n", command);
	449	DBF_LH(6, "device = %d:%d\n", tapeblock_major, minor);
	450
	451	switch (command) {
	452	/* Refuse some IOCTL calls without complaining (mount). */
	453	case 0x5310: /* CDROMMULTISESSION */
	454	rc = -EINVAL;
	455	break;
	456	default:
	457	PRINT_WARN("invalid ioctl 0x%x\n", command);
	458	rc = -EINVAL;
	459	}
	460
	461	return rc;
	462	}
	463
	464	/*
	465	* Initialize block device frontend.
	466	*/
	467	int
	468	tapeblock_init(void)
	469	{
	470	int rc;
	471
	472	/* Register the tape major number to the kernel */
	473	rc = register_blkdev(tapeblock_major, "tBLK");
	474	if (rc < 0)
	475	return rc;
	476
	477	if (tapeblock_major == 0)
	478	tapeblock_major = rc;
	479	PRINT_INFO("tape gets major %d for block device\n", tapeblock_major);
	480	return 0;
	481	}
	482
	483	/*
	484	* Deregister major for block device frontend
	485	*/
	486	void
	487	tapeblock_exit(void)
	488	{
	489	unregister_blkdev(tapeblock_major, "tBLK");
	490	}