[PATCH v3 5/5] scsi: target: core: Add RTPI attribute for target port

[Dmitry Bogdanov <d.bogdanov@xxxxxxxxx>]

RELATIVE TARGET PORT IDENTIFIER can be read and configured via configfs:
$ echo 0x10 > $TARGET/tpgt_N/attrib/rtpi

RTPI can be changed only on disabled target ports.

Signed-off-by: Roman Bolshakov <r.bolshakov@xxxxxxxxx>
Signed-off-by: Dmitry Bogdanov <d.bogdanov@xxxxxxxxx>
---
 drivers/target/target_core_tpg.c  | 55 +++++++++++++++++++++++++++++--
 include/target/target_core_base.h |  1 +
 2 files changed, 54 insertions(+), 2 deletions(-)

diff --git a/drivers/target/target_core_tpg.c b/drivers/target/target_core_tpg.c
index f39e69050db6..24ca10b455fb 100644
--- a/drivers/target/target_core_tpg.c
+++ b/drivers/target/target_core_tpg.c
@@ -442,8 +442,23 @@ static void core_tpg_lun_ref_release(struct percpu_ref *ref)
 
 static int target_tpg_register_rtpi(struct se_portal_group *se_tpg)
 {
-	return xa_alloc(&tpg_xa, &se_tpg->tpg_rtpi, se_tpg,
+	int ret;
+
+	if (se_tpg->rtpi_manual) {
+		ret = xa_insert(&tpg_xa, se_tpg->tpg_rtpi, se_tpg, GFP_KERNEL);
+		if (ret) {
+			pr_info("%s_TPG[%hu] - Can not set RTPI %#x, it is already busy",
+				se_tpg->se_tpg_tfo->fabric_name,
+				se_tpg->se_tpg_tfo->tpg_get_tag(se_tpg),
+				se_tpg->tpg_rtpi);
+			return -EINVAL;
+		}
+	} else {
+		ret = xa_alloc(&tpg_xa, &se_tpg->tpg_rtpi, se_tpg,
 			       XA_LIMIT(1, USHRT_MAX), GFP_KERNEL);
+	}
+
+	return ret;
 }
 
 static void target_tpg_deregister_rtpi(struct se_portal_group *se_tpg)
@@ -652,7 +667,7 @@ int core_tpg_add_lun(
 	return ret;
 }
 
-void core_tpg_remove_lun(
+void target_tpg_remove_lun(
 	struct se_portal_group *tpg,
 	struct se_lun *lun)
 {
@@ -692,6 +707,42 @@ void core_tpg_remove_lun(
 	percpu_ref_exit(&lun->lun_ref);
 }
 
+static ssize_t target_tpg_rtpi_show(struct config_item *item, char *page)
+{
+	struct se_portal_group *se_tpg = attrib_to_tpg(item);
+
+	return sysfs_emit(page, "%#x\n", se_tpg->tpg_rtpi);
+}
+
+static ssize_t target_tpg_rtpi_store(struct config_item *item,
+				   const char *page, size_t count)
+{
+	struct se_portal_group *se_tpg = attrib_to_tpg(item);
+	u16 val;
+	int ret;
+
+	ret = kstrtou16(page, 0, &val);
+	if (ret < 0)
+		return ret;
+	if (val == 0)
+		return -EINVAL;
+
+	if (se_tpg->enabled) {
+		pr_info("%s_TPG[%hu] - Can not change RTPI on enabled TPG",
+			se_tpg->se_tpg_tfo->fabric_name,
+			se_tpg->se_tpg_tfo->tpg_get_tag(se_tpg));
+		return -EINVAL;
+	}
+
+	se_tpg->tpg_rtpi = val;
+	se_tpg->rtpi_manual = true;
+
+	return count;
+}
+
+CONFIGFS_ATTR(target_tpg_, rtpi);
+
 struct configfs_attribute *core_tpg_attrib_attrs[] = {
+	&target_tpg_attr_rtpi,
 	NULL,
 };
diff --git a/include/target/target_core_base.h b/include/target/target_core_base.h
index 2e6de5ba8172..29fb036511e5 100644
--- a/include/target/target_core_base.h
+++ b/include/target/target_core_base.h
@@ -918,6 +918,7 @@ struct se_portal_group {
 	bool			enabled;
 	/* RELATIVE TARGET PORT IDENTIFIER */
 	u32			tpg_rtpi;
+	bool			rtpi_manual;
 	/* Used for PR SPEC_I_PT=1 and REGISTER_AND_MOVE */
 	atomic_t		tpg_pr_ref_count;
 	/* Spinlock for adding/removing ACLed Nodes */
-- 
2.25.1