scsi: ufs: Use UFS device indicated maximum LU number

According to Jedec standard UFS 3.0 and UFS 2.1 Spec, Maximum number of
logical units supported by the UFS device is indicated by parameter
bMaxNumberLU in Geometry Descriptor. This patch is to delete current hard
code macro definition of UFS_UPIU_MAX_GENERAL_LUN, and switch to use device
indicated number instead.

Link: https://lore.kernel.org/r/20200120130820.1737-9-huobean@gmail.comReviewed-by: Asutosh Das <asutoshd@codeaurora.org>
Reviewed-by: Alim Akhtar <alim.akhtar@samsung.com>
Signed-off-by: Bean Huo <beanhuo@micron.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/ufs/ufs-sysfs.c

@@ -713,7 +713,7 @@ static ssize_t _pname##_show(struct device *dev,			\
 	struct scsi_device *sdev = to_scsi_device(dev);			\
 	struct ufs_hba *hba = shost_priv(sdev->host);			\
 	u8 lun = ufshcd_scsi_to_upiu_lun(sdev->lun);			\
-	if (!ufs_is_valid_unit_desc_lun(lun))				\
+	if (!ufs_is_valid_unit_desc_lun(&hba->dev_info, lun))		\
 		return -EINVAL;						\
 	return ufs_sysfs_read_desc_param(hba, QUERY_DESC_IDN_##_duname,	\
 		lun, _duname##_DESC_PARAM##_puname, buf, _size);	\

drivers/scsi/ufs/ufs.h

@@ -63,7 +63,6 @@
 #define UFS_UPIU_MAX_UNIT_NUM_ID	0x7F
 #define UFS_MAX_LUNS		(SCSI_W_LUN_BASE + UFS_UPIU_MAX_UNIT_NUM_ID)
 #define UFS_UPIU_WLUN_ID	(1 << 7)
-#define UFS_UPIU_MAX_GENERAL_LUN	8
 
 /* Well known logical unit id in LUN field of UPIU */
 enum {
@@ -539,12 +538,19 @@ struct ufs_dev_info {
 
 /**
  * ufs_is_valid_unit_desc_lun - checks if the given LUN has a unit descriptor
+ * @dev_info: pointer of instance of struct ufs_dev_info
  * @lun: LU number to check
  * @return: true if the lun has a matching unit descriptor, false otherwise
  */
-static inline bool ufs_is_valid_unit_desc_lun(u8 lun)
+static inline bool ufs_is_valid_unit_desc_lun(struct ufs_dev_info *dev_info,
+		u8 lun)
 {
-	return lun == UFS_UPIU_RPMB_WLUN || (lun < UFS_UPIU_MAX_GENERAL_LUN);
+	if (!dev_info || !dev_info->max_lu_supported) {
+		pr_err("Max General LU supported by UFS isn't initilized\n");
+		return false;
+	}
+
+	return lun == UFS_UPIU_RPMB_WLUN || (lun < dev_info->max_lu_supported);
 }
 
 #endif /* End of Header */

drivers/scsi/ufs/ufshcd.c

@@ -3269,7 +3269,7 @@ static inline int ufshcd_read_unit_desc_param(struct ufs_hba *hba,
 	 * Unit descriptors are only available for general purpose LUs (LUN id
 	 * from 0 to 7) and RPMB Well known LU.
 	 */
-	if (!ufs_is_valid_unit_desc_lun(lun))
+	if (!ufs_is_valid_unit_desc_lun(&hba->dev_info, lun))
 		return -EOPNOTSUPP;
 
 	return ufshcd_read_desc_param(hba, QUERY_DESC_IDN_UNIT, lun,
@@ -4528,7 +4528,7 @@ static int ufshcd_get_lu_wp(struct ufs_hba *hba,
 	 * protected so skip reading bLUWriteProtect parameter for
 	 * it. For other W-LUs, UNIT DESCRIPTOR is not available.
 	 */
-	else if (lun >= UFS_UPIU_MAX_GENERAL_LUN)
+	else if (lun >= hba->dev_info.max_lu_supported)
 		ret = -ENOTSUPP;
 	else
 		ret = ufshcd_read_unit_desc_param(hba,