tape_core.c

linux-2.6.15.6

			break;
		default:
			DBF_EVENT(3, "(%08x): Set offline failed "
				"- drive in use.\n",
				device->cdev_id);
			PRINT_WARN("(%s): Set offline failed "
				"- drive in use.\n",
				device->cdev->dev.bus_id);
			spin_unlock_irq(get_ccwdev_lock(device->cdev));
			return -EBUSY;
	}

	DBF_LH(3, "(%08x): Drive set offline.\n", device->cdev_id);
	return 0;
}

/*
 * Allocate memory for a new device structure.
 */
static struct tape_device *
tape_alloc_device(void)
{
	struct tape_device *device;

	device = (struct tape_device *)
		kmalloc(sizeof(struct tape_device), GFP_KERNEL);
	if (device == NULL) {
		DBF_EXCEPTION(2, "ti:no mem\n");
		PRINT_INFO ("can't allocate memory for "
			    "tape info structure\n");
		return ERR_PTR(-ENOMEM);
	}
	memset(device, 0, sizeof(struct tape_device));
	device->modeset_byte = (char *) kmalloc(1, GFP_KERNEL | GFP_DMA);
	if (device->modeset_byte == NULL) {
		DBF_EXCEPTION(2, "ti:no mem\n");
		PRINT_INFO("can't allocate memory for modeset byte\n");
		kfree(device);
		return ERR_PTR(-ENOMEM);
	}
	INIT_LIST_HEAD(&device->req_queue);
	INIT_LIST_HEAD(&device->node);
	init_waitqueue_head(&device->state_change_wq);
	device->tape_state = TS_INIT;
	device->medium_state = MS_UNKNOWN;
	*device->modeset_byte = 0;
	device->first_minor = -1;
	atomic_set(&device->ref_count, 1);
	INIT_WORK(&device->tape_dnr, tape_delayed_next_request, device);

	return device;
}

/*
 * Get a reference to an existing device structure. This will automatically
 * increment the reference count.
 */
struct tape_device *
tape_get_device_reference(struct tape_device *device)
{
	DBF_EVENT(4, "tape_get_device_reference(%p) = %i\n", device,
		atomic_inc_return(&device->ref_count));

	return device;
}

/*
 * Decrease the reference counter of a devices structure. If the
 * reference counter reaches zero free the device structure.
 * The function returns a NULL pointer to be used by the caller
 * for clearing reference pointers.
 */
struct tape_device *
tape_put_device(struct tape_device *device)
{
	int remain;

	remain = atomic_dec_return(&device->ref_count);
	if (remain > 0) {
		DBF_EVENT(4, "tape_put_device(%p) -> %i\n", device, remain);
	} else {
		if (remain < 0) {
			DBF_EVENT(4, "put device without reference\n");
			PRINT_ERR("put device without reference\n");
		} else {
			DBF_EVENT(4, "tape_free_device(%p)\n", device);
			kfree(device->modeset_byte);
			kfree(device);
		}
	}

	return NULL;			
}

/*
 * Find tape device by a device index.
 */
struct tape_device *
tape_get_device(int devindex)
{
	struct tape_device *device, *tmp;

	device = ERR_PTR(-ENODEV);
	read_lock(&tape_device_lock);
	list_for_each_entry(tmp, &tape_device_list, node) {
		if (tmp->first_minor / TAPE_MINORS_PER_DEV == devindex) {
			device = tape_get_device_reference(tmp);
			break;
		}
	}
	read_unlock(&tape_device_lock);
	return device;
}

/*
 * Driverfs tape probe function.
 */
int
tape_generic_probe(struct ccw_device *cdev)
{
	struct tape_device *device;

	device = tape_alloc_device();
	if (IS_ERR(device))
		return -ENODEV;
	PRINT_INFO("tape device %s found\n", cdev->dev.bus_id);
	cdev->dev.driver_data = device;
	device->cdev = cdev;
	device->cdev_id = busid_to_int(cdev->dev.bus_id);
	cdev->handler = __tape_do_irq;

	ccw_device_set_options(cdev, CCWDEV_DO_PATHGROUP);
	sysfs_create_group(&cdev->dev.kobj, &tape_attr_group);

	return 0;
}

static inline void
__tape_discard_requests(struct tape_device *device)
{
	struct tape_request *	request;
	struct list_head *	l, *n;

	list_for_each_safe(l, n, &device->req_queue) {
		request = list_entry(l, struct tape_request, list);
		if (request->status == TAPE_REQUEST_IN_IO)
			request->status = TAPE_REQUEST_DONE;
		list_del(&request->list);

		/* Decrease ref_count for removed request. */
		request->device = tape_put_device(device);
		request->rc = -EIO;
		if (request->callback != NULL)
			request->callback(request, request->callback_data);
	}
}

/*
 * Driverfs tape remove function.
 *
 * This function is called whenever the common I/O layer detects the device
 * gone. This can happen at any time and we cannot refuse.
 */
void
tape_generic_remove(struct ccw_device *cdev)
{
	struct tape_device *	device;

	device = cdev->dev.driver_data;
	if (!device) {
		PRINT_ERR("No device pointer in tape_generic_remove!\n");
		return;
	}
	DBF_LH(3, "(%08x): tape_generic_remove(%p)\n", device->cdev_id, cdev);

	spin_lock_irq(get_ccwdev_lock(device->cdev));
	switch (device->tape_state) {
		case TS_INIT:
			tape_state_set(device, TS_NOT_OPER);
		case TS_NOT_OPER:
			/*
			 * Nothing to do.
			 */
			spin_unlock_irq(get_ccwdev_lock(device->cdev));
			break;
		case TS_UNUSED:
			/*
			 * Need only to release the device.
			 */
			tape_state_set(device, TS_NOT_OPER);
			spin_unlock_irq(get_ccwdev_lock(device->cdev));
			tape_cleanup_device(device);
			break;
		default:
			/*
			 * There may be requests on the queue. We will not get
			 * an interrupt for a request that was running. So we
			 * just post them all as I/O errors.
			 */
			DBF_EVENT(3, "(%08x): Drive in use vanished!\n",
				device->cdev_id);
			PRINT_WARN("(%s): Drive in use vanished - "
				"expect trouble!\n",
				device->cdev->dev.bus_id);
			PRINT_WARN("State was %i\n", device->tape_state);
			tape_state_set(device, TS_NOT_OPER);
			__tape_discard_requests(device);
			spin_unlock_irq(get_ccwdev_lock(device->cdev));
			tape_cleanup_device(device);
	}

	if (cdev->dev.driver_data != NULL) {
		sysfs_remove_group(&cdev->dev.kobj, &tape_attr_group);
		cdev->dev.driver_data = tape_put_device(cdev->dev.driver_data);
	}
}

/*
 * Allocate a new tape ccw request
 */
struct tape_request *
tape_alloc_request(int cplength, int datasize)
{
	struct tape_request *request;

	if (datasize > PAGE_SIZE || (cplength*sizeof(struct ccw1)) > PAGE_SIZE)
		BUG();

	DBF_LH(6, "tape_alloc_request(%d, %d)\n", cplength, datasize);

	request = (struct tape_request *) kmalloc(sizeof(struct tape_request),
						  GFP_KERNEL);
	if (request == NULL) {
		DBF_EXCEPTION(1, "cqra nomem\n");
		return ERR_PTR(-ENOMEM);
	}
	memset(request, 0, sizeof(struct tape_request));
	/* allocate channel program */
	if (cplength > 0) {
		request->cpaddr = kmalloc(cplength*sizeof(struct ccw1),
					  GFP_ATOMIC | GFP_DMA);
		if (request->cpaddr == NULL) {
			DBF_EXCEPTION(1, "cqra nomem\n");
			kfree(request);
			return ERR_PTR(-ENOMEM);
		}
		memset(request->cpaddr, 0, cplength*sizeof(struct ccw1));
	}
	/* alloc small kernel buffer */
	if (datasize > 0) {
		request->cpdata = kmalloc(datasize, GFP_KERNEL | GFP_DMA);
		if (request->cpdata == NULL) {
			DBF_EXCEPTION(1, "cqra nomem\n");
			kfree(request->cpaddr);
			kfree(request);
			return ERR_PTR(-ENOMEM);
		}
		memset(request->cpdata, 0, datasize);
	}
	DBF_LH(6, "New request %p(%p/%p)\n", request, request->cpaddr,
		request->cpdata);

	return request;
}

/*
 * Free tape ccw request
 */
void
tape_free_request (struct tape_request * request)
{
	DBF_LH(6, "Free request %p\n", request);

	if (request->device != NULL) {
		request->device = tape_put_device(request->device);
	}
	kfree(request->cpdata);
	kfree(request->cpaddr);
	kfree(request);
}

static inline int
__tape_start_io(struct tape_device *device, struct tape_request *request)
{
	int rc;

#ifdef CONFIG_S390_TAPE_BLOCK
	if (request->op == TO_BLOCK)
		device->discipline->check_locate(device, request);
#endif
	rc = ccw_device_start(
		device->cdev,
		request->cpaddr,
		(unsigned long) request,
		0x00,
		request->options
	);
	if (rc == 0) {
		request->status = TAPE_REQUEST_IN_IO;
	} else if (rc == -EBUSY) {
		/* The common I/O subsystem is currently busy. Retry later. */
		request->status = TAPE_REQUEST_QUEUED;
		schedule_work(&device->tape_dnr);
		rc = 0;
	} else {
		/* Start failed. Remove request and indicate failure. */
		DBF_EVENT(1, "tape: start request failed with RC = %i\n", rc);
	}
	return rc;
}

static inline void
__tape_start_next_request(struct tape_device *device)
{
	struct list_head *l, *n;
	struct tape_request *request;
	int rc;

	DBF_LH(6, "__tape_start_next_request(%p)\n", device);
	/*
	 * Try to start each request on request queue until one is
	 * started successful.
	 */
	list_for_each_safe(l, n, &device->req_queue) {
		request = list_entry(l, struct tape_request, list);

		/*
		 * Avoid race condition if bottom-half was triggered more than
		 * once.
		 */
		if (request->status == TAPE_REQUEST_IN_IO)
			return;

		/*
		 * We wanted to cancel the request but the common I/O layer
		 * was busy at that time. This can only happen if this
		 * function is called by delayed_next_request.
		 * Otherwise we start the next request on the queue.
		 */
		if (request->status == TAPE_REQUEST_CANCEL) {
			rc = __tape_cancel_io(device, request);
		} else {
			rc = __tape_start_io(device, request);
		}
		if (rc == 0)
			return;

		/* Set ending status. */
		request->rc = rc;
		request->status = TAPE_REQUEST_DONE;

		/* Remove from request queue. */
		list_del(&request->list);

		/* Do callback. */
		if (request->callback != NULL)
			request->callback(request, request->callback_data);
	}
}

static void
tape_delayed_next_request(void *data)
{
	struct tape_device *	device;

	device = (struct tape_device *) data;
	DBF_LH(6, "tape_delayed_next_request(%p)\n", device);
	spin_lock_irq(get_ccwdev_lock(device->cdev));
	__tape_start_next_request(device);
	spin_unlock_irq(get_ccwdev_lock(device->cdev));
}

static inline void
__tape_end_request(
	struct tape_device *	device,
	struct tape_request *	request,
	int			rc)
{
	DBF_LH(6, "__tape_end_request(%p, %p, %i)\n", device, request, rc);
	if (request) {
		request->rc = rc;
		request->status = TAPE_REQUEST_DONE;

		/* Remove from request queue. */
		list_del(&request->list);

		/* Do callback. */
		if (request->callback != NULL)
			request->callback(request, request->callback_data);
	}

	/* Start next request. */
	if (!list_empty(&device->req_queue))
		__tape_start_next_request(device);
}

/*
 * Write sense data to console/dbf
 */
void
tape_dump_sense(struct tape_device* device, struct tape_request *request,
		struct irb *irb)
{
	unsigned int *sptr;

	PRINT_INFO("-------------------------------------------------\n");
	PRINT_INFO("DSTAT : %02x  CSTAT: %02x	CPA: %04x\n",
		   irb->scsw.dstat, irb->scsw.cstat, irb->scsw.cpa);
	PRINT_INFO("DEVICE: %s\n", device->cdev->dev.bus_id);
	if (request != NULL)
		PRINT_INFO("OP	  : %s\n", tape_op_verbose[request->op]);

	sptr = (unsigned int *) irb->ecw;
	PRINT_INFO("Sense data: %08X %08X %08X %08X \n",
		   sptr[0], sptr[1], sptr[2], sptr[3]);
	PRINT_INFO("Sense data: %08X %08X %08X %08X \n",
		   sptr[4], sptr[5], sptr[6], sptr[7]);
	PRINT_INFO("--------------------------------------------------\n");
}

/*
 * Write sense data to dbf
 */
void
tape_dump_sense_dbf(struct tape_device *device, struct tape_request *request,
		    struct irb *irb)
{
	unsigned int *sptr;
	const char* op;

	if (request != NULL)