iscsi,iser-target: Expose supported protection ops according to t10_pi

iSER will report supported protection operations based on
the tpg attribute t10_pi settings and HCA PI offload capabilities.
If the HCA does not support PI offload or tpg attribute t10_pi is
not set, we fall to SW PI mode.

In order to do that, we move iscsit_get_sup_prot_ops after connection
tpg assignment.

Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Cc: <stable@vger.kernel.org> # v3.14+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

drivers/infiniband/ulp/isert/ib_isert.c

@@ -64,7 +64,7 @@ struct rdma_cm_id *isert_setup_id(struct isert_np *isert_np);
 static inline bool
 isert_prot_cmd(struct isert_conn *conn, struct se_cmd *cmd)
 {
-	return (conn->conn_device->pi_capable &&
+	return (conn->pi_support &&
 		cmd->prot_op != TARGET_PROT_NORMAL);
 }
 
@@ -2324,8 +2324,16 @@ isert_get_sup_prot_ops(struct iscsi_conn *conn)
 	struct isert_conn *isert_conn = (struct isert_conn *)conn->context;
 	struct isert_device *device = isert_conn->conn_device;
 
-	if (device->pi_capable)
-		return TARGET_PROT_ALL;
+	if (conn->tpg->tpg_attrib.t10_pi) {
+		if (device->pi_capable) {
+			pr_info("conn %p PI offload enabled\n", isert_conn);
+			isert_conn->pi_support = true;
+			return TARGET_PROT_ALL;
+		}
+	}
+
+	pr_info("conn %p PI offload disabled\n", isert_conn);
+	isert_conn->pi_support = false;
 
 	return TARGET_PROT_NORMAL;
 }

drivers/infiniband/ulp/isert/ib_isert.h

@@ -128,6 +128,7 @@ struct isert_conn {
 	atomic_t		post_send_buf_count;
 	u32			responder_resources;
 	u32			initiator_depth;
+	bool			pi_support;
 	u32			max_sge;
 	char			*login_buf;
 	char			*login_req_buf;