Initial commit: Linux kernel 4.19 for Unplugged OS

drivers/target/loopback/Kconfig

@@ -0,0 +1,6 @@
+config LOOPBACK_TARGET
+	tristate "TCM Virtual SAS target and Linux/SCSI LDD fabric loopback module"
+	depends on SCSI
+	help
+	  Say Y here to enable the TCM Virtual SAS target and Linux/SCSI LLD
+	  fabric loopback module.

drivers/target/loopback/Makefile

@@ -0,0 +1 @@
+obj-$(CONFIG_LOOPBACK_TARGET)	+= tcm_loop.o

drivers/target/loopback/tcm_loop.h

@@ -0,0 +1,55 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#include <linux/types.h>
+#include <linux/device.h>
+#include <target/target_core_base.h> /* struct se_cmd */
+
+#define TCM_LOOP_VERSION		"v2.1-rc2"
+#define TL_WWN_ADDR_LEN			256
+#define TL_TPGS_PER_HBA			32
+
+struct tcm_loop_cmd {
+	/* State of Linux/SCSI CDB+Data descriptor */
+	u32 sc_cmd_state;
+	/* Tagged command queueing */
+	u32 sc_cmd_tag;
+	/* Pointer to the CDB+Data descriptor from Linux/SCSI subsystem */
+	struct scsi_cmnd *sc;
+	/* The TCM I/O descriptor that is accessed via container_of() */
+	struct se_cmd tl_se_cmd;
+	struct work_struct work;
+	struct completion tmr_done;
+	/* Sense buffer that will be mapped into outgoing status */
+	unsigned char tl_sense_buf[TRANSPORT_SENSE_BUFFER];
+};
+
+struct tcm_loop_nexus {
+	/*
+	 * Pointer to TCM session for I_T Nexus
+	 */
+	struct se_session *se_sess;
+};
+
+#define TCM_TRANSPORT_ONLINE 0
+#define TCM_TRANSPORT_OFFLINE 1
+
+struct tcm_loop_tpg {
+	unsigned short tl_tpgt;
+	unsigned short tl_transport_status;
+	enum target_prot_type tl_fabric_prot_type;
+	atomic_t tl_tpg_port_count;
+	struct se_portal_group tl_se_tpg;
+	struct tcm_loop_hba *tl_hba;
+	struct tcm_loop_nexus *tl_nexus;
+};
+
+struct tcm_loop_hba {
+	u8 tl_proto_id;
+	unsigned char tl_wwn_address[TL_WWN_ADDR_LEN];
+	struct se_hba_s *se_hba;
+	struct se_lun *tl_hba_lun;
+	struct se_port *tl_hba_lun_sep;
+	struct device dev;
+	struct Scsi_Host *sh;
+	struct tcm_loop_tpg tl_hba_tpgs[TL_TPGS_PER_HBA];
+	struct se_wwn tl_hba_wwn;
+};