Target/sbc: Set protection operation and relevant checks

SBC-3 mandates the protection checks that must be
performed in the rdprotect/wrprotect field. Use them.
According to backstore device pi_attributes and
cdb rdprotect/wrprotect field.

(Fix incorrect se_cmd->prot_type -> TARGET_PROT_NORMAL
comparision in transport_generic_new_cmd - nab)
(Fix missing break in sbc_set_prot_op_checks - DanC + Sagi)

Signed-off-by: Sagi Grimberg <[e-mail]>
Signed-off-by: Nicholas Bellinger <[e-mail]>

drivers/target/target_core_sbc.c

···
 	return TCM_NO_SENSE;
 }
 
+static int
+sbc_set_prot_op_checks(u8 protect, enum target_prot_type prot_type,
+		       bool is_write, struct se_cmd *cmd)
+{
+	if (is_write) {
+		cmd->prot_op = protect ? TARGET_PROT_DOUT_PASS :
+					 TARGET_PROT_DOUT_INSERT;
+		switch (protect) {
+		case 0x0:
+		case 0x3:
+			cmd->prot_checks = 0;
+			break;
+		case 0x1:
+		case 0x5:
+			cmd->prot_checks = TARGET_DIF_CHECK_GUARD;
+			if (prot_type == TARGET_DIF_TYPE1_PROT)
+				cmd->prot_checks |= TARGET_DIF_CHECK_REFTAG;
+			break;
+		case 0x2:
+			if (prot_type == TARGET_DIF_TYPE1_PROT)
+				cmd->prot_checks = TARGET_DIF_CHECK_REFTAG;
+			break;
+		case 0x4:
+			cmd->prot_checks = TARGET_DIF_CHECK_GUARD;
+			break;
+		default:
+			pr_err("Unsupported protect field %d\n", protect);
+			return -EINVAL;
+		}
+	} else {
+		cmd->prot_op = protect ? TARGET_PROT_DIN_PASS :
+					 TARGET_PROT_DIN_STRIP;
+		switch (protect) {
+		case 0x0:
+		case 0x1:
+		case 0x5:
+			cmd->prot_checks = TARGET_DIF_CHECK_GUARD;
+			if (prot_type == TARGET_DIF_TYPE1_PROT)
+				cmd->prot_checks |= TARGET_DIF_CHECK_REFTAG;
+			break;
+		case 0x2:
+			if (prot_type == TARGET_DIF_TYPE1_PROT)
+				cmd->prot_checks = TARGET_DIF_CHECK_REFTAG;
+			break;
+		case 0x3:
+			cmd->prot_checks = 0;
+			break;
+		case 0x4:
+			cmd->prot_checks = TARGET_DIF_CHECK_GUARD;
+			break;
+		default:
+			pr_err("Unsupported protect field %d\n", protect);
+			return -EINVAL;
+		}
+	}
+
+	return 0;
+}
+
 static bool
 sbc_check_prot(struct se_device *dev, struct se_cmd *cmd, unsigned char *cdb,
-	       u32 sectors)
+	       u32 sectors, bool is_write)
 {
+	u8 protect = cdb[1] >> 5;
+
 	if (!cmd->t_prot_sg || !cmd->t_prot_nents)
 		return true;
 
 	switch (dev->dev_attrib.pi_prot_type) {
 	case TARGET_DIF_TYPE3_PROT:
-		if (!(cdb[1] & 0xe0))
-			return true;
-
 		cmd->reftag_seed = 0xffffffff;
 		break;
 	case TARGET_DIF_TYPE2_PROT:
-		if (cdb[1] & 0xe0)
+		if (protect)
 			return false;
 
 		cmd->reftag_seed = cmd->t_task_lba;
 		break;
 	case TARGET_DIF_TYPE1_PROT:
-		if (!(cdb[1] & 0xe0))
-			return true;
-
 		cmd->reftag_seed = cmd->t_task_lba;
 		break;
 	case TARGET_DIF_TYPE0_PROT:
 	default:
 		return true;
 	}
+
+	if (sbc_set_prot_op_checks(protect, dev->dev_attrib.pi_prot_type,
+				   is_write, cmd))
+		return false;
 
 	cmd->prot_type = dev->dev_attrib.pi_prot_type;
 	cmd->prot_length = dev->prot_length * sectors;
···
 		sectors = transport_get_sectors_10(cdb);
 		cmd->t_task_lba = transport_lba_32(cdb);
 
-		if (!sbc_check_prot(dev, cmd, cdb, sectors))
+		if (!sbc_check_prot(dev, cmd, cdb, sectors, false))
 			return TCM_UNSUPPORTED_SCSI_OPCODE;
 
 		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
···
 		sectors = transport_get_sectors_12(cdb);
 		cmd->t_task_lba = transport_lba_32(cdb);
 
-		if (!sbc_check_prot(dev, cmd, cdb, sectors))
+		if (!sbc_check_prot(dev, cmd, cdb, sectors, false))
 			return TCM_UNSUPPORTED_SCSI_OPCODE;
 
 		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
···
 		sectors = transport_get_sectors_16(cdb);
 		cmd->t_task_lba = transport_lba_64(cdb);
 
-		if (!sbc_check_prot(dev, cmd, cdb, sectors))
+		if (!sbc_check_prot(dev, cmd, cdb, sectors, false))
 			return TCM_UNSUPPORTED_SCSI_OPCODE;
 
 		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
···
 		sectors = transport_get_sectors_10(cdb);
 		cmd->t_task_lba = transport_lba_32(cdb);
 
-		if (!sbc_check_prot(dev, cmd, cdb, sectors))
+		if (!sbc_check_prot(dev, cmd, cdb, sectors, true))
 			return TCM_UNSUPPORTED_SCSI_OPCODE;
 
 		if (cdb[1] & 0x8)
···
 		sectors = transport_get_sectors_12(cdb);
 		cmd->t_task_lba = transport_lba_32(cdb);
 
-		if (!sbc_check_prot(dev, cmd, cdb, sectors))
+		if (!sbc_check_prot(dev, cmd, cdb, sectors, true))
 			return TCM_UNSUPPORTED_SCSI_OPCODE;
 
 		if (cdb[1] & 0x8)
···
 		sectors = transport_get_sectors_16(cdb);
 		cmd->t_task_lba = transport_lba_64(cdb);
 
-		if (!sbc_check_prot(dev, cmd, cdb, sectors))
+		if (!sbc_check_prot(dev, cmd, cdb, sectors, true))
 			return TCM_UNSUPPORTED_SCSI_OPCODE;
 
 		if (cdb[1] & 0x8)

drivers/target/target_core_transport.c

···
 				return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 		}
 
-		if (cmd->prot_type != TARGET_PROT_NORMAL) {
+		if (cmd->prot_op != TARGET_PROT_NORMAL) {
 			ret = target_alloc_sgl(&cmd->t_prot_sg,
 					       &cmd->t_prot_nents,
 					       cmd->prot_length, true);

include/target/target_core_base.h

···
 	TARGET_DIF_TYPE3_PROT,
 };
 
+enum target_core_dif_check {
+	TARGET_DIF_CHECK_GUARD  = 0x1 << 0,
+	TARGET_DIF_CHECK_APPTAG = 0x1 << 1,
+	TARGET_DIF_CHECK_REFTAG = 0x1 << 2,
+};
+
 struct se_dif_v1_tuple {
 	__be16			guard_tag;
 	__be16			app_tag;
···
 	/* DIF related members */
 	enum target_prot_op	prot_op;
 	enum target_prot_type	prot_type;
+	u8			prot_checks;
 	u32			prot_length;
 	u32			reftag_seed;
 	struct scatterlist	*t_prot_sg;