target: Add per device xcopy_lun for copy offload I/O

This patch adds a se_device->xcopy_lun that is used for local
copy offload I/O, instead of allocating + initializing a pseudo
se_lun for each received EXTENDED_COPY operation.

Also, move declaration of struct se_lun + struct se_port_stat_grps
ahead of struct se_device.

Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
diff --git a/include/target/target_core_base.h b/include/target/target_core_base.h
index 1ad0a42..96bf1b0 100644
--- a/include/target/target_core_base.h
+++ b/include/target/target_core_base.h
@@ -627,6 +627,34 @@
 	struct config_group da_group;
 };
 
+struct se_port_stat_grps {
+	struct config_group stat_group;
+	struct config_group scsi_port_group;
+	struct config_group scsi_tgt_port_group;
+	struct config_group scsi_transport_group;
+};
+
+struct se_lun {
+#define SE_LUN_LINK_MAGIC			0xffff7771
+	u32			lun_link_magic;
+	/* See transport_lun_status_table */
+	enum transport_lun_status_table lun_status;
+	u32			lun_access;
+	u32			lun_flags;
+	u32			unpacked_lun;
+	atomic_t		lun_acl_count;
+	spinlock_t		lun_acl_lock;
+	spinlock_t		lun_sep_lock;
+	struct completion	lun_shutdown_comp;
+	struct list_head	lun_acl_list;
+	struct se_device	*lun_se_dev;
+	struct se_port		*lun_sep;
+	struct config_group	lun_group;
+	struct se_port_stat_grps port_stat_grps;
+	struct completion	lun_ref_comp;
+	struct percpu_ref	lun_ref;
+};
+
 struct se_dev_stat_grps {
 	struct config_group stat_group;
 	struct config_group scsi_dev_group;
@@ -710,6 +738,7 @@
 	struct se_subsystem_api *transport;
 	/* Linked list for struct se_hba struct se_device list */
 	struct list_head	dev_list;
+	struct se_lun		xcopy_lun;
 };
 
 struct se_hba {
@@ -729,34 +758,6 @@
 	struct se_subsystem_api *transport;
 };
 
-struct se_port_stat_grps {
-	struct config_group stat_group;
-	struct config_group scsi_port_group;
-	struct config_group scsi_tgt_port_group;
-	struct config_group scsi_transport_group;
-};
-
-struct se_lun {
-#define SE_LUN_LINK_MAGIC			0xffff7771
-	u32			lun_link_magic;
-	/* See transport_lun_status_table */
-	enum transport_lun_status_table lun_status;
-	u32			lun_access;
-	u32			lun_flags;
-	u32			unpacked_lun;
-	atomic_t		lun_acl_count;
-	spinlock_t		lun_acl_lock;
-	spinlock_t		lun_sep_lock;
-	struct completion	lun_shutdown_comp;
-	struct list_head	lun_acl_list;
-	struct se_device	*lun_se_dev;
-	struct se_port		*lun_sep;
-	struct config_group	lun_group;
-	struct se_port_stat_grps port_stat_grps;
-	struct completion	lun_ref_comp;
-	struct percpu_ref	lun_ref;
-};
-
 struct scsi_port_stats {
        u64     cmd_pdus;
        u64     tx_data_octets;