vmur.c

linux 内核源代码

		}
		res = 0;
		copied += len;
	} while (copied != count);

	*offs += copied;
	rc = copied;
fail:
	free_page((unsigned long) buf);
	return rc;
}

static ssize_t ur_read(struct file *file, char __user *ubuf, size_t count,
		       loff_t *offs)
{
	struct urdev *urd;
	int rc;

	TRACE("ur_read: count=%zu ppos=%li\n", count, (unsigned long) *offs);

	if (count == 0)
		return 0;

	urd = ((struct urfile *) file->private_data)->urd;
	rc = mutex_lock_interruptible(&urd->io_mutex);
	if (rc)
		return rc;
	rc = diag14_read(file, ubuf, count, offs);
	mutex_unlock(&urd->io_mutex);
	return rc;
}

/*
 * diagnose code 0x14 subcode 0x0fff - retrieve next file descriptor
 * cc=0  normal completion
 * cc=1  no files on reader queue or no subsequent file
 * cc=2  spid specified is invalid
 */
static int diag_read_next_file_info(struct file_control_block *buf, int spid)
{
	int cc;

	cc = diag14((unsigned long) buf, spid, 0xfff);
	switch (cc) {
	case 0:
		return 0;
	default:
		return -ENODATA;
	}
}

static int verify_uri_device(struct urdev *urd)
{
	struct file_control_block *fcb;
	char *buf;
	int rc;

	fcb = kmalloc(sizeof(*fcb), GFP_KERNEL | GFP_DMA);
	if (!fcb)
		return -ENOMEM;

	/* check for empty reader device (beginning of chain) */
	rc = diag_read_next_file_info(fcb, 0);
	if (rc)
		goto fail_free_fcb;

	/* if file is in hold status, we do not read it */
	if (fcb->file_stat & (FLG_SYSTEM_HOLD | FLG_USER_HOLD)) {
		rc = -EPERM;
		goto fail_free_fcb;
	}

	/* open file on virtual reader	*/
	buf = (char *) __get_free_page(GFP_KERNEL | GFP_DMA);
	if (!buf) {
		rc = -ENOMEM;
		goto fail_free_fcb;
	}
	rc = diag_read_file(urd->dev_id.devno, buf);
	if ((rc != 0) && (rc != -ENODATA)) /* EOF does not hurt */
		goto fail_free_buf;

	/* check if the file on top of the queue is open now */
	rc = diag_read_next_file_info(fcb, 0);
	if (rc)
		goto fail_free_buf;
	if (!(fcb->file_stat & FLG_IN_USE)) {
		rc = -EMFILE;
		goto fail_free_buf;
	}
	rc = 0;

fail_free_buf:
	free_page((unsigned long) buf);
fail_free_fcb:
	kfree(fcb);
	return rc;
}

static int verify_device(struct urdev *urd)
{
	switch (urd->class) {
	case DEV_CLASS_UR_O:
		return 0; /* no check needed here */
	case DEV_CLASS_UR_I:
		return verify_uri_device(urd);
	default:
		return -ENOTSUPP;
	}
}

static int get_uri_file_reclen(struct urdev *urd)
{
	struct file_control_block *fcb;
	int rc;

	fcb = kmalloc(sizeof(*fcb), GFP_KERNEL | GFP_DMA);
	if (!fcb)
		return -ENOMEM;
	rc = diag_read_next_file_info(fcb, 0);
	if (rc)
		goto fail_free;
	if (fcb->file_stat & FLG_CP_DUMP)
		rc = 0;
	else
		rc = fcb->rec_len;

fail_free:
	kfree(fcb);
	return rc;
}

static int get_file_reclen(struct urdev *urd)
{
	switch (urd->class) {
	case DEV_CLASS_UR_O:
		return 0;
	case DEV_CLASS_UR_I:
		return get_uri_file_reclen(urd);
	default:
		return -ENOTSUPP;
	}
}

static int ur_open(struct inode *inode, struct file *file)
{
	u16 devno;
	struct urdev *urd;
	struct urfile *urf;
	unsigned short accmode;
	int rc;

	accmode = file->f_flags & O_ACCMODE;

	if (accmode == O_RDWR)
		return -EACCES;

	/*
	 * We treat the minor number as the devno of the ur device
	 * to find in the driver tree.
	 */
	devno = MINOR(file->f_dentry->d_inode->i_rdev);

	urd = urdev_get_from_devno(devno);
	if (!urd)
		return -ENXIO;

	if (file->f_flags & O_NONBLOCK) {
		if (!mutex_trylock(&urd->open_mutex)) {
			rc = -EBUSY;
			goto fail_put;
		}
	} else {
		if (mutex_lock_interruptible(&urd->open_mutex)) {
			rc = -ERESTARTSYS;
			goto fail_put;
		}
	}

	TRACE("ur_open\n");

	if (((accmode == O_RDONLY) && (urd->class != DEV_CLASS_UR_I)) ||
	    ((accmode == O_WRONLY) && (urd->class != DEV_CLASS_UR_O))) {
		TRACE("ur_open: unsupported dev class (%d)\n", urd->class);
		rc = -EACCES;
		goto fail_unlock;
	}

	rc = verify_device(urd);
	if (rc)
		goto fail_unlock;

	urf = urfile_alloc(urd);
	if (!urf) {
		rc = -ENOMEM;
		goto fail_unlock;
	}

	urf->dev_reclen = urd->reclen;
	rc = get_file_reclen(urd);
	if (rc < 0)
		goto fail_urfile_free;
	urf->file_reclen = rc;
	file->private_data = urf;
	return 0;

fail_urfile_free:
	urfile_free(urf);
fail_unlock:
	mutex_unlock(&urd->open_mutex);
fail_put:
	urdev_put(urd);
	return rc;
}

static int ur_release(struct inode *inode, struct file *file)
{
	struct urfile *urf = file->private_data;

	TRACE("ur_release\n");
	mutex_unlock(&urf->urd->open_mutex);
	urdev_put(urf->urd);
	urfile_free(urf);
	return 0;
}

static loff_t ur_llseek(struct file *file, loff_t offset, int whence)
{
	loff_t newpos;

	if ((file->f_flags & O_ACCMODE) != O_RDONLY)
		return -ESPIPE; /* seek allowed only for reader */
	if (offset % PAGE_SIZE)
		return -ESPIPE; /* only multiples of 4K allowed */
	switch (whence) {
	case 0: /* SEEK_SET */
		newpos = offset;
		break;
	case 1: /* SEEK_CUR */
		newpos = file->f_pos + offset;
		break;
	default:
		return -EINVAL;
	}
	file->f_pos = newpos;
	return newpos;
}

static struct file_operations ur_fops = {
	.owner	 = THIS_MODULE,
	.open	 = ur_open,
	.release = ur_release,
	.read	 = ur_read,
	.write	 = ur_write,
	.llseek  = ur_llseek,
};

/*
 * ccw_device infrastructure:
 *     ur_probe creates the struct urdev (with refcount = 1), the device
 *     attributes, sets up the interrupt handler and validates the virtual
 *     unit record device.
 *     ur_remove removes the device attributes and drops the reference to
 *     struct urdev.
 *
 *     ur_probe, ur_remove, ur_set_online and ur_set_offline are serialized
 *     by the vmur_mutex lock.
 *
 *     urd->char_device is used as indication that the online function has
 *     been completed successfully.
 */
static int ur_probe(struct ccw_device *cdev)
{
	struct urdev *urd;
	int rc;

	TRACE("ur_probe: cdev=%p\n", cdev);

	mutex_lock(&vmur_mutex);
	urd = urdev_alloc(cdev);
	if (!urd) {
		rc = -ENOMEM;
		goto fail_unlock;
	}

	rc = ur_create_attributes(&cdev->dev);
	if (rc) {
		rc = -ENOMEM;
		goto fail_urdev_put;
	}
	cdev->handler = ur_int_handler;

	/* validate virtual unit record device */
	urd->class = get_urd_class(urd);
	if (urd->class < 0) {
		rc = urd->class;
		goto fail_remove_attr;
	}
	if ((urd->class != DEV_CLASS_UR_I) && (urd->class != DEV_CLASS_UR_O)) {
		rc = -ENOTSUPP;
		goto fail_remove_attr;
	}
	spin_lock_irq(get_ccwdev_lock(cdev));
	cdev->dev.driver_data = urd;
	spin_unlock_irq(get_ccwdev_lock(cdev));

	mutex_unlock(&vmur_mutex);
	return 0;

fail_remove_attr:
	ur_remove_attributes(&cdev->dev);
fail_urdev_put:
	urdev_put(urd);
fail_unlock:
	mutex_unlock(&vmur_mutex);
	return rc;
}

static int ur_set_online(struct ccw_device *cdev)
{
	struct urdev *urd;
	int minor, major, rc;
	char node_id[16];

	TRACE("ur_set_online: cdev=%p\n", cdev);

	mutex_lock(&vmur_mutex);
	urd = urdev_get_from_cdev(cdev);
	if (!urd) {
		/* ur_remove already deleted our urd */
		rc = -ENODEV;
		goto fail_unlock;
	}

	if (urd->char_device) {
		/* Another ur_set_online was faster */
		rc = -EBUSY;
		goto fail_urdev_put;
	}

	minor = urd->dev_id.devno;
	major = MAJOR(ur_first_dev_maj_min);

	urd->char_device = cdev_alloc();
	if (!urd->char_device) {
		rc = -ENOMEM;
		goto fail_urdev_put;
	}

	cdev_init(urd->char_device, &ur_fops);
	urd->char_device->dev = MKDEV(major, minor);
	urd->char_device->owner = ur_fops.owner;

	rc = cdev_add(urd->char_device, urd->char_device->dev, 1);
	if (rc)
		goto fail_free_cdev;
	if (urd->cdev->id.cu_type == READER_PUNCH_DEVTYPE) {
		if (urd->class == DEV_CLASS_UR_I)
			sprintf(node_id, "vmrdr-%s", cdev->dev.bus_id);
		if (urd->class == DEV_CLASS_UR_O)
			sprintf(node_id, "vmpun-%s", cdev->dev.bus_id);
	} else if (urd->cdev->id.cu_type == PRINTER_DEVTYPE) {
		sprintf(node_id, "vmprt-%s", cdev->dev.bus_id);
	} else {
		rc = -ENOTSUPP;
		goto fail_free_cdev;
	}

	urd->device = device_create(vmur_class, NULL, urd->char_device->dev,
					"%s", node_id);
	if (IS_ERR(urd->device)) {
		rc = PTR_ERR(urd->device);
		TRACE("ur_set_online: device_create rc=%d\n", rc);
		goto fail_free_cdev;
	}
	urdev_put(urd);
	mutex_unlock(&vmur_mutex);
	return 0;

fail_free_cdev:
	cdev_del(urd->char_device);
	urd->char_device = NULL;
fail_urdev_put:
	urdev_put(urd);
fail_unlock:
	mutex_unlock(&vmur_mutex);
	return rc;
}

static int ur_set_offline_force(struct ccw_device *cdev, int force)
{
	struct urdev *urd;
	int rc;

	TRACE("ur_set_offline: cdev=%p\n", cdev);
	urd = urdev_get_from_cdev(cdev);
	if (!urd)
		/* ur_remove already deleted our urd */
		return -ENODEV;
	if (!urd->char_device) {
		/* Another ur_set_offline was faster */
		rc = -EBUSY;
		goto fail_urdev_put;
	}
	if (!force && (atomic_read(&urd->ref_count) > 2)) {
		/* There is still a user of urd (e.g. ur_open) */
		TRACE("ur_set_offline: BUSY\n");
		rc = -EBUSY;
		goto fail_urdev_put;
	}
	device_destroy(vmur_class, urd->char_device->dev);
	cdev_del(urd->char_device);
	urd->char_device = NULL;
	rc = 0;

fail_urdev_put:
	urdev_put(urd);
	return rc;
}

static int ur_set_offline(struct ccw_device *cdev)
{
	int rc;

	mutex_lock(&vmur_mutex);
	rc = ur_set_offline_force(cdev, 0);
	mutex_unlock(&vmur_mutex);
	return rc;
}

static void ur_remove(struct ccw_device *cdev)
{
	unsigned long flags;

	TRACE("ur_remove\n");

	mutex_lock(&vmur_mutex);

	if (cdev->online)
		ur_set_offline_force(cdev, 1);
	ur_remove_attributes(&cdev->dev);

	spin_lock_irqsave(get_ccwdev_lock(cdev), flags);
	urdev_put(cdev->dev.driver_data);
	cdev->dev.driver_data = NULL;
	spin_unlock_irqrestore(get_ccwdev_lock(cdev), flags);

	mutex_unlock(&vmur_mutex);
}

/*
 * Module initialisation and cleanup
 */
static int __init ur_init(void)
{
	int rc;
	dev_t dev;

	if (!MACHINE_IS_VM) {
		PRINT_ERR("%s is only available under z/VM.\n", ur_banner);
		return -ENODEV;
	}

	vmur_dbf = debug_register("vmur", 4, 1, 4 * sizeof(long));
	if (!vmur_dbf)
		return -ENOMEM;
	rc = debug_register_view(vmur_dbf, &debug_sprintf_view);
	if (rc)
		goto fail_free_dbf;

	debug_set_level(vmur_dbf, 6);

	rc = ccw_driver_register(&ur_driver);
	if (rc)
		goto fail_free_dbf;

	rc = alloc_chrdev_region(&dev, 0, NUM_MINORS, "vmur");
	if (rc) {
		PRINT_ERR("alloc_chrdev_region failed: err = %d\n", rc);
		goto fail_unregister_driver;
	}
	ur_first_dev_maj_min = MKDEV(MAJOR(dev), 0);

	vmur_class = class_create(THIS_MODULE, "vmur");
	if (IS_ERR(vmur_class)) {
		rc = PTR_ERR(vmur_class);
		goto fail_unregister_region;
	}
	PRINT_INFO("%s loaded.\n", ur_banner);
	return 0;

fail_unregister_region:
	unregister_chrdev_region(ur_first_dev_maj_min, NUM_MINORS);
fail_unregister_driver:
	ccw_driver_unregister(&ur_driver);
fail_free_dbf:
	debug_unregister(vmur_dbf);
	return rc;
}

static void __exit ur_exit(void)
{
	class_destroy(vmur_class);
	unregister_chrdev_region(ur_first_dev_maj_min, NUM_MINORS);
	ccw_driver_unregister(&ur_driver);
	debug_unregister(vmur_dbf);
	PRINT_INFO("%s unloaded.\n", ur_banner);
}

module_init(ur_init);
module_exit(ur_exit);