[PATCH 2/2] [SCSI] ufs: calculate read/write xfer len from cdb

[Santosh Y <santoshsy@gmail.com>]

Currently the Expected data transfer length field in
command UPIU is being updated with "transfersize" from
the scsi_cmnd struct. But, if the read/write data
transfer size exceeds the sector size, the "transfersize"
will be truncated to the sector size. Thanks to KOBAYASHI
Yoshitake for pointing it out.

This patch ensures that the correct read/write data transfer
size is calculated from the "transfer length" available in the
CDB.

Reported-by: KOBAYASHI Yoshitake <yoshitake.kobayashi@toshiba.co.jp>
Reviewed-by: Vinayak Holikatti <vinholikatti@gmail.com>
Signed-off-by: Santosh Y <santoshsy@gmail.com>
---
 drivers/scsi/ufs/ufshcd.c |   37 ++++++++++++++++++++++++++++++++++++-
 1 files changed, 36 insertions(+), 1 deletions(-)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 1878cd8..4f99ab4 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -585,6 +585,41 @@ static void ufshcd_int_config(struct ufs_hba *hba, u32 option)
 }
 
 /**
+ * ufshcd_get_transfer_len - calculate data transfer size for read/write
+ *			     commands from the CDB
+ * @cmdp: pointer to SCSI command
+ */
+static inline u32 ufshcd_get_transfer_len(struct scsi_cmnd *cmdp)
+{
+	u32 transfer_len;
+
+	switch (cmdp->cmnd[0]) {
+	case READ_6:
+	case WRITE_6:
+		transfer_len = cmdp->device->sector_size *
+			       cmdp->cmnd[4];
+		break;
+	case READ_10:
+	case WRITE_10:
+		transfer_len = cmdp->device->sector_size *
+			       ((cmdp->cmnd[7] << 8) |
+				cmdp->cmnd[8]);
+		break;
+	case READ_16:
+	case WRITE_16:
+		transfer_len = cmdp->device->sector_size *
+			       ((cmdp->cmnd[10] << 24) |
+				(cmdp->cmnd[11] << 16) |
+				(cmdp->cmnd[12] << 8) |
+				cmdp->cmnd[13]);
+		break;
+	default:
+		transfer_len = cmdp->transfersize;
+	}
+	return transfer_len;
+}
+
+/**
  * ufshcd_compose_upiu - form UFS Protocol Information Unit(UPIU)
  * @lrb - pointer to local reference block
  */
@@ -640,7 +675,7 @@ static void ufshcd_compose_upiu(struct ufshcd_lrb *lrbp)
 		ucd_cmd_ptr->header.dword_2 = 0;
 
 		ucd_cmd_ptr->exp_data_transfer_len =
-			cpu_to_be32(lrbp->cmd->transfersize);
+			cpu_to_be32(ufshcd_get_transfer_len(lrbp->cmd));
 
 		memcpy(ucd_cmd_ptr->cdb,
 		       lrbp->cmd->cmnd,
-- 
1.7.5.4