static int sd_open(struct block_device *bdev, fmode_t mode)
{
	struct scsi_disk *sdkp = scsi_disk_get(bdev->bd_disk);
	struct scsi_device *sdev;
	int retval;

	if (!sdkp)
		return -ENXIO;

	SCSI_LOG_HLQUEUE(3, sd_printk(KERN_INFO, sdkp, "sd_open\n"));

	sdev = sdkp->device;

	retval = scsi_autopm_get_device(sdev);
	if (retval)
		goto error_autopm;

	/*
	 * If the device is in error recovery, wait until it is done.
	 * If the device is offline, then disallow any access to it.
	 */
	retval = -ENXIO;
	if (!scsi_block_when_processing_errors(sdev))
		goto error_out;

	if (sdev->removable || sdkp->write_prot)
		check_disk_change(bdev);

	/*
	 * If the drive is empty, just let the open fail.
	 */
	retval = -ENOMEDIUM;
	if (sdev->removable && !sdkp->media_present && !(mode & FMODE_NDELAY))
		goto error_out;

	/*
	 * If the device has the write protect tab set, have the open fail
	 * if the user expects to be able to write to the thing.
	 */
	retval = -EROFS;
	if (sdkp->write_prot && (mode & FMODE_WRITE))
		goto error_out;

	/*
	 * It is possible that the disk changing stuff resulted in
	 * the device being taken offline.  If this is the case,
	 * report this to the user, and don't pretend that the
	 * open actually succeeded.
	 */
	retval = -ENXIO;
	if (!scsi_device_online(sdev))
		goto error_out;

	if ((atomic_inc_return(&sdkp->openers) == 1) && sdev->removable) {
		if (scsi_block_when_processing_errors(sdev))
			scsi_set_medium_removal(sdev, SCSI_REMOVAL_PREVENT);
	}

	return 0;

error_out:
	scsi_autopm_put_device(sdev);
error_autopm:
	scsi_disk_put(sdkp);
	return retval;	
}
static int sd_open(struct block_device *bdev, fmode_t mode)
{
	struct scsi_disk *sdkp = scsi_disk_get(bdev->bd_disk);
	struct scsi_device *sdev;
	int retval;

	if (!sdkp)
		return -ENXIO;

	SCSI_LOG_HLQUEUE(3, sd_printk(KERN_INFO, sdkp, "sd_open\n"));

	sdev = sdkp->device;

	retval = scsi_autopm_get_device(sdev);
	if (retval)
		goto error_autopm;

	 
	retval = -ENXIO;
	if (!scsi_block_when_processing_errors(sdev))
		goto error_out;

	if (sdev->removable || sdkp->write_prot)
		check_disk_change(bdev);

	 
	retval = -ENOMEDIUM;
	if (sdev->removable && !sdkp->media_present && !(mode & FMODE_NDELAY))
		goto error_out;

	 
	retval = -EROFS;
	if (sdkp->write_prot && (mode & FMODE_WRITE))
		goto error_out;

	 
	retval = -ENXIO;
	if (!scsi_device_online(sdev))
		goto error_out;

	if ((atomic_inc_return(&sdkp->openers) == 1) && sdev->removable) {
		if (scsi_block_when_processing_errors(sdev))
			scsi_set_medium_removal(sdev, SCSI_REMOVAL_PREVENT);
	}

	return 0;

error_out:
	scsi_autopm_put_device(sdev);
error_autopm:
	scsi_disk_put(sdkp);
	return retval;	
}