[PATCH 20/33] TCMU PR: add a func to register an existing reg

[Zhu Lingshan]

This patch added a function tcmu_execute_pr_register_existing()
which will handle Persistent Reservation registration for a
currently registered IT_Nexus.

Signed-off-by: Zhu Lingshan <ls...@suse.com>
---
 drivers/target/target_core_user.c | 34 +++++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)

diff --git a/drivers/target/target_core_user.c 
b/drivers/target/target_core_user.c
index a6e951f04065..4b426a9061b1 100644
--- a/drivers/target/target_core_user.c
+++ b/drivers/target/target_core_user.c
@@ -2614,6 +2614,40 @@ static int tcmu_pr_info_unregister_reg(struct 
tcmu_pr_info *pr_info,
        return 0;
 }
 
+/* handle PR registration for a currently registered I_T nexus */
+static sense_reason_t
+tcmu_execute_pr_register_existing(struct tcmu_pr_info *pr_info,
+                                 u64 old_key, u64 new_key, char *it_nexus,
+                                 struct tcmu_pr_reg *existing_reg,
+                                 bool ignore_existing)
+{
+       sense_reason_t ret;
+       int rc;
+
+       pr_debug("PR registration for registered nexus: %s\n", it_nexus);
+
+       if (!ignore_existing && (old_key != existing_reg->key)) {
+               ret = TCM_RESERVATION_CONFLICT;
+               goto out;
+       }
+
+       if (new_key == 0) {
+               /* unregister */
+               rc = tcmu_pr_info_unregister_reg(pr_info, existing_reg);
+               if (rc < 0) {
+                       ret = TCM_OUT_OF_RESOURCES;
+                       goto out;
+               }
+       } else {
+               /* update key */
+               existing_reg->key = new_key;
+       }
+
+       ret = TCM_NO_SENSE;
+out:
+       return ret;
+}
+
 static int tcmu_configure_device(struct se_device *dev)
 {
        struct tcmu_dev *udev = TCMU_DEV(dev);
-- 
2.17.1