iscsi-target: Refactor RX PDU logic + export request PDU handling

This patch refactors existing traditional iscsi RX side PDU handling
to use iscsit_transport, and exports the necessary logic for external
transport modules.

This includes:

- Refactor iscsit_handle_scsi_cmd() into PDU setup / processing
- Add updated iscsit_handle_scsi_cmd() for tradtional iscsi code
- Add iscsit_set_unsoliticed_dataout() wrapper
- Refactor iscsit_handle_data_out() into PDU check / processing
- Add updated iscsit_handle_data_out() for tradtional iscsi code
- Add iscsit_handle_nop_out() + iscsit_handle_task_mgt_cmd() to
  accept pre-allocated struct iscsi_cmd
- Add iscsit_build_r2ts_for_cmd() caller for iscsi_target_transport
  to handle ISTATE_SEND_R2T for TX immediate queue
- Refactor main traditional iscsi iscsi_target_rx_thread() PDU switch
  into iscsi_target_rx_opcode() using iscsit_allocate_cmd()
- Turn iscsi_target_rx_thread() process context into NOP for
  ib_isert side work-queue.

v5 changes:

- Make iscsit_handle_scsi_cmd() static (Fengguang)
- Fix iscsit_handle_scsi_cmd() exception se_cmd leak (nab)

v3 changes:
- Add extra target_put_sess_cmd call in iscsit_add_reject_from_cmd
  after completion

v2 changes:

- Disable iscsit_ack_from_expstatsn() usage for RDMAExtentions=Yes
- Disable iscsit_allocate_datain_req() usage for RDMAExtentions=Yes
- Add target_get_sess_cmd() reference counting to
  iscsit_setup_scsi_cmd()
- Add TFO->lio_check_stop_free() fabric API caller
- Add export of iscsit_stop_dataout_timer() symbol
- Add iscsit_build_r2ts_for_cmd() for iscsit_transport->iscsit_get_dataout()
- Convert existing usage of iscsit_build_r2ts_for_cmd() to
  ->iscsit_get_dataout()
- Drop RDMAExtentions=Yes specific check in iscsit_build_r2ts_for_cmd()
- Fix RDMAExtentions -> RDMAExtensions typo (andy)
- Pass correct dump_payload value into iscsit_get_immediate_data()
  for iscsit_handle_scsi_cmd()
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

drivers/target/iscsi/iscsi_target.h

@@ -16,11 +16,12 @@ extern int iscsit_reset_np_thread(struct iscsi_np *, struct iscsi_tpg_np *,
 				struct iscsi_portal_group *);
 extern int iscsit_del_np(struct iscsi_np *);
 extern int iscsit_add_reject_from_cmd(u8, int, int, unsigned char *, struct iscsi_cmd *);
+extern void iscsit_set_unsoliticed_dataout(struct iscsi_cmd *);
 extern int iscsit_logout_closesession(struct iscsi_cmd *, struct iscsi_conn *);
 extern int iscsit_logout_closeconnection(struct iscsi_cmd *, struct iscsi_conn *);
 extern int iscsit_logout_removeconnforrecovery(struct iscsi_cmd *, struct iscsi_conn *);
 extern int iscsit_send_async_msg(struct iscsi_conn *, u16, u8, u8);
-extern int iscsit_build_r2ts_for_cmd(struct iscsi_cmd *, struct iscsi_conn *, bool recovery);
+extern int iscsit_build_r2ts_for_cmd(struct iscsi_conn *, struct iscsi_cmd *, bool recovery);
 extern void iscsit_thread_get_cpumask(struct iscsi_conn *);
 extern int iscsi_target_tx_thread(void *);
 extern int iscsi_target_rx_thread(void *);

drivers/target/iscsi/iscsi_target_configfs.c

@@ -1543,9 +1543,10 @@ static int lio_queue_data_in(struct se_cmd *se_cmd)
 static int lio_write_pending(struct se_cmd *se_cmd)
 {
 	struct iscsi_cmd *cmd = container_of(se_cmd, struct iscsi_cmd, se_cmd);
+	struct iscsi_conn *conn = cmd->conn;
 
 	if (!cmd->immediate_data && !cmd->unsolicited_data)
-		return iscsit_build_r2ts_for_cmd(cmd, cmd->conn, false);
+		return conn->conn_transport->iscsit_get_dataout(conn, cmd, false);
 
 	return 0;
 }
@@ -1696,6 +1697,11 @@ static void lio_set_default_node_attributes(struct se_node_acl *se_acl)
 	iscsit_set_default_node_attribues(acl);
 }
 
+static int lio_check_stop_free(struct se_cmd *se_cmd)
+{
+	return target_put_sess_cmd(se_cmd->se_sess, se_cmd);
+}
+
 static void lio_release_cmd(struct se_cmd *se_cmd)
 {
 	struct iscsi_cmd *cmd = container_of(se_cmd, struct iscsi_cmd, se_cmd);
@@ -1741,6 +1747,7 @@ int iscsi_target_register_configfs(void)
 	fabric->tf_ops.tpg_alloc_fabric_acl = &lio_tpg_alloc_fabric_acl;
 	fabric->tf_ops.tpg_release_fabric_acl = &lio_tpg_release_fabric_acl;
 	fabric->tf_ops.tpg_get_inst_index = &lio_tpg_get_inst_index;
+	fabric->tf_ops.check_stop_free = &lio_check_stop_free,
 	fabric->tf_ops.release_cmd = &lio_release_cmd;
 	fabric->tf_ops.shutdown_session = &lio_tpg_shutdown_session;
 	fabric->tf_ops.close_session = &lio_tpg_close_session;

drivers/target/iscsi/iscsi_target_erl1.c

@@ -22,6 +22,7 @@
 #include <scsi/iscsi_proto.h>
 #include <target/target_core_base.h>
 #include <target/target_core_fabric.h>
+#include <target/iscsi/iscsi_transport.h>
 
 #include "iscsi_target_core.h"
 #include "iscsi_target_seq_pdu_list.h"
@@ -53,6 +54,9 @@ int iscsit_dump_data_payload(
 	u32 length, padding, offset = 0, size;
 	struct kvec iov;
 
+	if (conn->sess->sess_ops->RDMAExtensions)
+		return 0;
+
 	length = (buf_len > OFFLOAD_BUF_SIZE) ? OFFLOAD_BUF_SIZE : buf_len;
 
 	buf = kzalloc(length, GFP_ATOMIC);
@@ -919,6 +923,7 @@ int iscsit_execute_ooo_cmdsns(struct iscsi_session *sess)
 int iscsit_execute_cmd(struct iscsi_cmd *cmd, int ooo)
 {
 	struct se_cmd *se_cmd = &cmd->se_cmd;
+	struct iscsi_conn *conn = cmd->conn;
 	int lr = 0;
 
 	spin_lock_bh(&cmd->istate_lock);
@@ -981,7 +986,7 @@ int iscsit_execute_cmd(struct iscsi_cmd *cmd, int ooo)
 					return 0;
 
 				iscsit_set_dataout_sequence_values(cmd);
-				iscsit_build_r2ts_for_cmd(cmd, cmd->conn, false);
+				conn->conn_transport->iscsit_get_dataout(conn, cmd, false);
 			}
 			return 0;
 		}
@@ -999,10 +1004,7 @@ int iscsit_execute_cmd(struct iscsi_cmd *cmd, int ooo)
 			if (transport_check_aborted_status(se_cmd, 1) != 0)
 				return 0;
 
-			iscsit_set_dataout_sequence_values(cmd);
-			spin_lock_bh(&cmd->dataout_timeout_lock);
-			iscsit_start_dataout_timer(cmd, cmd->conn);
-			spin_unlock_bh(&cmd->dataout_timeout_lock);
+			iscsit_set_unsoliticed_dataout(cmd);
 		}
 		return transport_handle_cdb_direct(&cmd->se_cmd);
 
@@ -1290,3 +1292,4 @@ void iscsit_stop_dataout_timer(struct iscsi_cmd *cmd)
 			cmd->init_task_tag);
 	spin_unlock_bh(&cmd->dataout_timeout_lock);
 }
+EXPORT_SYMBOL(iscsit_stop_dataout_timer);

drivers/target/iscsi/iscsi_target_login.c

@@ -1068,8 +1068,7 @@ int iscsit_get_login_rx(struct iscsi_conn *conn, struct iscsi_login *login)
 	if (login->first_request) {
 		login_req = (struct iscsi_login_req *)login->req;
 		login->leading_connection = (!login_req->tsih) ? 1 : 0;
-		login->current_stage	=
-			(login_req->flags & ISCSI_FLAG_LOGIN_CURRENT_STAGE_MASK) >> 2;
+		login->current_stage	= ISCSI_LOGIN_CURRENT_STAGE(login_req->flags);
 		login->version_min	= login_req->min_version;
 		login->version_max	= login_req->max_version;
 		memcpy(login->isid, login_req->isid, 6);

drivers/target/iscsi/iscsi_target_nego.c

@@ -691,21 +691,6 @@ int iscsi_target_locate_portal(
 	login_req = (struct iscsi_login_req *) login->req;
 	payload_length = ntoh24(login_req->dlength);
 
-	login->first_request	= 1;
-	login->leading_connection = (!login_req->tsih) ? 1 : 0;
-	login->current_stage	= ISCSI_LOGIN_CURRENT_STAGE(login_req->flags);
-	login->version_min	= login_req->min_version;
-	login->version_max	= login_req->max_version;
-	memcpy(login->isid, login_req->isid, 6);
-	login->cmd_sn		= be32_to_cpu(login_req->cmdsn);
-	login->init_task_tag	= login_req->itt;
-	login->initial_exp_statsn = be32_to_cpu(login_req->exp_statsn);
-	login->cid		= be16_to_cpu(login_req->cid);
-	login->tsih		= be16_to_cpu(login_req->tsih);
-
-	if (iscsi_target_get_initial_payload(conn, login) < 0)
-		return -1;
-
 	tmpbuf = kzalloc(payload_length + 1, GFP_KERNEL);
 	if (!tmpbuf) {
 		pr_err("Unable to allocate memory for tmpbuf.\n");

drivers/target/iscsi/iscsi_target_tmr.c

@@ -23,6 +23,7 @@
 #include <scsi/iscsi_proto.h>
 #include <target/target_core_base.h>
 #include <target/target_core_fabric.h>
+#include <target/iscsi/iscsi_transport.h>
 
 #include "iscsi_target_core.h"
 #include "iscsi_target_seq_pdu_list.h"
@@ -301,7 +302,7 @@ static int iscsit_task_reassign_complete_write(
 	/*
 	 * iscsit_build_r2ts_for_cmd() can handle the rest from here.
 	 */
-	return iscsit_build_r2ts_for_cmd(cmd, conn, true);
+	return conn->conn_transport->iscsit_get_dataout(conn, cmd, true);
 }
 
 static int iscsit_task_reassign_complete_read(

drivers/target/iscsi/iscsi_target_util.c

@@ -317,6 +317,7 @@ int iscsit_sequence_cmd(
 
 	return ret;
 }
+EXPORT_SYMBOL(iscsit_sequence_cmd);
 
 int iscsit_check_unsolicited_dataout(struct iscsi_cmd *cmd, unsigned char *buf)
 {