scsi: Rework the code for caching Vital Product Data (VPD)

EXPORT_SYMBOL_GPL(scsi_get_vpd_page);

/**

 * scsi_attach_vpd - Attach Vital Product Data to a SCSI device structure

 * scsi_get_vpd_buf - Get Vital Product Data from a SCSI device

 * @sdev: The device to ask

 * @page: Which Vital Product Data to return

 * @len: Upon success, the VPD length will be stored in *@len.

 *

 * Attach the 'Device Identification' VPD page (0x83) and the

 * 'Unit Serial Number' VPD page (0x80) to a SCSI device

 * structure. This information can be used to identify the device

 * uniquely.

 * Returns %NULL upon failure.

 */

void scsi_attach_vpd(struct scsi_device *sdev)

static unsigned char *scsi_get_vpd_buf(struct scsi_device *sdev, u8 page,

				       int *len)

{

	int result, i;

	int vpd_len = SCSI_VPD_PG_LEN;

	int pg80_supported = 0;

	int pg83_supported = 0;

	unsigned char __rcu *vpd_buf, *orig_vpd_buf = NULL;

	if (!scsi_device_supports_vpd(sdev))

		return;

	unsigned char *vpd_buf;

	int vpd_len = SCSI_VPD_PG_LEN, result;

retry_pg0:

retry_pg:

	vpd_buf = kmalloc(vpd_len, GFP_KERNEL);

	if (!vpd_buf)

		return;

		return NULL;

	/* Ask for all the pages supported by this device */

	result = scsi_vpd_inquiry(sdev, vpd_buf, 0, vpd_len);

	result = scsi_vpd_inquiry(sdev, vpd_buf, page, vpd_len);

	if (result < 0) {

		kfree(vpd_buf);

		return;

		return NULL;

	}

	if (result > vpd_len) {

		vpd_len = result;

		kfree(vpd_buf);

		goto retry_pg0;

		goto retry_pg;

	}

	for (i = 4; i < result; i++) {

		if (vpd_buf[i] == 0x80)

			pg80_supported = 1;

		if (vpd_buf[i] == 0x83)

			pg83_supported = 1;

	*len = result;

	return vpd_buf;

}

	kfree(vpd_buf);

	vpd_len = SCSI_VPD_PG_LEN;

	if (pg80_supported) {

retry_pg80:

		vpd_buf = kmalloc(vpd_len, GFP_KERNEL);

static void scsi_update_vpd_page(struct scsi_device *sdev, u8 page,

				 unsigned char __rcu **sdev_vpd_buf,

				 int *sdev_vpd_len)

{

	unsigned char *vpd_buf;

	int len;

	vpd_buf = scsi_get_vpd_buf(sdev, page, &len);

	if (!vpd_buf)

		return;

		result = scsi_vpd_inquiry(sdev, vpd_buf, 0x80, vpd_len);

		if (result < 0) {

			kfree(vpd_buf);

			return;

		}

		if (result > vpd_len) {

			vpd_len = result;

			kfree(vpd_buf);

			goto retry_pg80;

		}

	mutex_lock(&sdev->inquiry_mutex);

		orig_vpd_buf = sdev->vpd_pg80;

		sdev->vpd_pg80_len = result;

		rcu_assign_pointer(sdev->vpd_pg80, vpd_buf);

	rcu_swap_protected(*sdev_vpd_buf, vpd_buf,

			   lockdep_is_held(&sdev->inquiry_mutex));

	*sdev_vpd_len = len;

	mutex_unlock(&sdev->inquiry_mutex);

	synchronize_rcu();

		if (orig_vpd_buf) {

			kfree(orig_vpd_buf);

			orig_vpd_buf = NULL;

		}

		vpd_len = SCSI_VPD_PG_LEN;

	kfree(vpd_buf);

}

	if (pg83_supported) {

retry_pg83:

		vpd_buf = kmalloc(vpd_len, GFP_KERNEL);

		if (!vpd_buf)

/**

 * scsi_attach_vpd - Attach Vital Product Data to a SCSI device structure

 * @sdev: The device to ask

 *

 * Attach the 'Device Identification' VPD page (0x83) and the

 * 'Unit Serial Number' VPD page (0x80) to a SCSI device

 * structure. This information can be used to identify the device

 * uniquely.

 */

void scsi_attach_vpd(struct scsi_device *sdev)

{

	int i, vpd_len;

	unsigned char *vpd_buf;

	if (!scsi_device_supports_vpd(sdev))

		return;

		result = scsi_vpd_inquiry(sdev, vpd_buf, 0x83, vpd_len);

		if (result < 0) {

			kfree(vpd_buf);

	/* Ask for all the pages supported by this device */

	vpd_buf = scsi_get_vpd_buf(sdev, 0, &vpd_len);

	if (!vpd_buf)

		return;

	for (i = 4; i < vpd_len; i++) {

		if (vpd_buf[i] == 0x80)

			scsi_update_vpd_page(sdev, 0x80, &sdev->vpd_pg80,

					     &sdev->vpd_pg80_len);

		if (vpd_buf[i] == 0x83)

			scsi_update_vpd_page(sdev, 0x83, &sdev->vpd_pg83,

					     &sdev->vpd_pg83_len);

	}

		if (result > vpd_len) {

			vpd_len = result;

	kfree(vpd_buf);

			goto retry_pg83;

		}

		mutex_lock(&sdev->inquiry_mutex);

		orig_vpd_buf = sdev->vpd_pg83;

		sdev->vpd_pg83_len = result;

		rcu_assign_pointer(sdev->vpd_pg83, vpd_buf);

		mutex_unlock(&sdev->inquiry_mutex);

		synchronize_rcu();

		if (orig_vpd_buf)

			kfree(orig_vpd_buf);

	}

}

/**