target: Add global device list for EXTENDED_COPY

EXTENDED_COPY needs to be able to search a global list of devices
based on NAA WWN device identifiers, so add a simple g_device_list
protected by g_device_mutex.

Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Martin Petersen <martin.petersen@oracle.com>
Cc: Chris Mason <chris.mason@fusionio.com>
Cc: Roland Dreier <roland@purestorage.com>
Cc: Zach Brown <zab@redhat.com>
Cc: James Bottomley <JBottomley@Parallels.com>
Cc: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: NNicholas Bellinger <nab@daterainc.com>

drivers/target/target_core_device.c

@@ -47,6 +47,9 @@
 #include "target_core_pr.h"
 #include "target_core_ua.h"
 
+DEFINE_MUTEX(g_device_mutex);
+LIST_HEAD(g_device_list);
+
 static struct se_hba *lun0_hba;
 /* not static, needed by tpg.c */
 struct se_device *g_lun0_dev;
@@ -1406,6 +1409,7 @@ struct se_device *target_alloc_device(struct se_hba *hba, const char *name)
 	INIT_LIST_HEAD(&dev->delayed_cmd_list);
 	INIT_LIST_HEAD(&dev->state_list);
 	INIT_LIST_HEAD(&dev->qf_cmd_list);
+	INIT_LIST_HEAD(&dev->g_dev_node);
 	spin_lock_init(&dev->stats_lock);
 	spin_lock_init(&dev->execute_task_lock);
 	spin_lock_init(&dev->delayed_cmd_lock);
@@ -1525,6 +1529,11 @@ int target_configure_device(struct se_device *dev)
 	spin_lock(&hba->device_lock);
 	hba->dev_count++;
 	spin_unlock(&hba->device_lock);
+
+	mutex_lock(&g_device_mutex);
+	list_add_tail(&dev->g_dev_node, &g_device_list);
+	mutex_unlock(&g_device_mutex);
+
 	return 0;
 
 out_free_alua:
@@ -1543,6 +1552,10 @@ void target_free_device(struct se_device *dev)
 	if (dev->dev_flags & DF_CONFIGURED) {
 		destroy_workqueue(dev->tmr_wq);
 
+		mutex_lock(&g_device_mutex);
+		list_del(&dev->g_dev_node);
+		mutex_unlock(&g_device_mutex);
+
 		spin_lock(&hba->device_lock);
 		hba->dev_count--;
 		spin_unlock(&hba->device_lock);

include/target/target_core_base.h

@@ -686,6 +686,7 @@ struct se_device {
 	struct list_head	delayed_cmd_list;
 	struct list_head	state_list;
 	struct list_head	qf_cmd_list;
+	struct list_head	g_dev_node;
 	/* Pointer to associated SE HBA */
 	struct se_hba		*se_hba;
 	/* T10 Inquiry and VPD WWN Information */