Commit 8f1f7d29 authored by Dmitry Bogdanov's avatar Dmitry Bogdanov Committed by Martin K. Petersen
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scsi: target: iscsi: Add support for extended CDB AHS 

Variable length SCSI commands are transferred over iSCSI via two CDB
buffers - in Basic Header Segment and in Additional Header Segment (AHS).
Since AHS is not supported yet, a target reads just BHS (48 byte) from TCP
and treats the remaining octets as a next new iSCSI PDU that causes
protocol errors.

Add support for the Extended CDB AHS type.

Link: https://lore.kernel.org/r/20220718152555.17084-2-d.bogdanov@yadro.com


Reviewed-by: default avatarMike Christie <michael.christie@oracle.com>
Signed-off-by: default avatarDmitry Bogdanov <d.bogdanov@yadro.com>
Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
parent 2f3b3200

drivers/target/iscsi/iscsi_target.c

+52 −3
Original line number Diff line number Diff line
@@ -1004,8 +1004,10 @@ int iscsit_setup_scsi_cmd(struct iscsit_conn *conn, struct iscsit_cmd *cmd, 
			  unsigned char *buf)

{

	int data_direction, payload_length;

	struct iscsi_ecdb_ahdr *ecdb_ahdr;

	struct iscsi_scsi_req *hdr;

	int iscsi_task_attr;

	unsigned char *cdb;

	int sam_task_attr;



	atomic_long_inc(&conn->sess->cmd_pdus);
@@ -1106,6 +1108,27 @@ int iscsit_setup_scsi_cmd(struct iscsit_conn *conn, struct iscsit_cmd *cmd, 
					     ISCSI_REASON_BOOKMARK_INVALID, buf);

	}



	cdb = hdr->cdb;



	if (hdr->hlength) {

		ecdb_ahdr = (struct iscsi_ecdb_ahdr *) (hdr + 1);

		if (ecdb_ahdr->ahstype != ISCSI_AHSTYPE_CDB) {

			pr_err("Additional Header Segment type %d not supported!\n",

			       ecdb_ahdr->ahstype);

			return iscsit_add_reject_cmd(cmd,

				ISCSI_REASON_CMD_NOT_SUPPORTED, buf);

		}



		cdb = kmalloc(be16_to_cpu(ecdb_ahdr->ahslength) + 15,

			      GFP_KERNEL);

		if (cdb == NULL)

			return iscsit_add_reject_cmd(cmd,

				ISCSI_REASON_BOOKMARK_NO_RESOURCES, buf);

		memcpy(cdb, hdr->cdb, ISCSI_CDB_SIZE);

		memcpy(cdb + ISCSI_CDB_SIZE, ecdb_ahdr->ecdb,

		       be16_to_cpu(ecdb_ahdr->ahslength) - 1);

	}



	data_direction = (hdr->flags & ISCSI_FLAG_CMD_WRITE) ? DMA_TO_DEVICE :

			 (hdr->flags & ISCSI_FLAG_CMD_READ) ? DMA_FROM_DEVICE :

			  DMA_NONE;
@@ -1153,9 +1176,12 @@ int iscsit_setup_scsi_cmd(struct iscsit_conn *conn, struct iscsit_cmd *cmd, 
		struct iscsi_datain_req *dr;



		dr = iscsit_allocate_datain_req();

		if (!dr)

		if (!dr) {

			if (cdb != hdr->cdb)

				kfree(cdb);

			return iscsit_add_reject_cmd(cmd,

					ISCSI_REASON_BOOKMARK_NO_RESOURCES, buf);

		}



		iscsit_attach_datain_req(cmd, dr);

	}
@@ -1176,9 +1202,12 @@ int iscsit_setup_scsi_cmd(struct iscsit_conn *conn, struct iscsit_cmd *cmd, 
	target_get_sess_cmd(&cmd->se_cmd, true);



	cmd->se_cmd.tag = (__force u32)cmd->init_task_tag;

	cmd->sense_reason = target_cmd_init_cdb(&cmd->se_cmd, hdr->cdb,

	cmd->sense_reason = target_cmd_init_cdb(&cmd->se_cmd, cdb,

						GFP_KERNEL);



	if (cdb != hdr->cdb)

		kfree(cdb);



	if (cmd->sense_reason) {

		if (cmd->sense_reason == TCM_OUT_OF_RESOURCES) {

			return iscsit_add_reject_cmd(cmd,
@@ -4036,8 +4065,9 @@ static bool iscsi_target_check_conn_state(struct iscsit_conn *conn) 
static void iscsit_get_rx_pdu(struct iscsit_conn *conn)

{

	int ret;

	u8 *buffer, opcode;

	u8 *buffer, *tmp_buf, opcode;

	u32 checksum = 0, digest = 0;

	struct iscsi_hdr *hdr;

	struct kvec iov;



	buffer = kcalloc(ISCSI_HDR_LEN, sizeof(*buffer), GFP_KERNEL);
@@ -4062,6 +4092,25 @@ static void iscsit_get_rx_pdu(struct iscsit_conn *conn) 
			break;

		}



		hdr = (struct iscsi_hdr *) buffer;

		if (hdr->hlength) {

			iov.iov_len = hdr->hlength * 4;

			tmp_buf = krealloc(buffer,

					  ISCSI_HDR_LEN + iov.iov_len,

					  GFP_KERNEL);

			if (!tmp_buf)

				break;



			buffer = tmp_buf;

			iov.iov_base = &buffer[ISCSI_HDR_LEN];



			ret = rx_data(conn, &iov, 1, iov.iov_len);

			if (ret != iov.iov_len) {

				iscsit_rx_thread_wait_for_tcp(conn);

				break;

			}

		}



		if (conn->conn_ops->HeaderDigest) {

			iov.iov_base	= &digest;

			iov.iov_len	= ISCSI_CRC_LEN;