iscsi-target: add void (*iscsit_release_cmd)()

Add void (*iscsit_release_cmd)() to
struct iscsit_transport, iscsi-target
uses this callback to release transport
driver resources associated with an iSCSI cmd.

cxgbit.ko needs this callback to release DDP
resource and sg page in case of
PASSTHROUGH_SG_TO_MEM_NOALLOC.
Signed-off-by: Varun Prakash <varun@chelsio.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

drivers/target/iscsi/iscsi_target_util.c

@@ -725,6 +725,9 @@ void __iscsit_free_cmd(struct iscsi_cmd *cmd, bool scsi_cmd,
 		iscsit_remove_cmd_from_immediate_queue(cmd, conn);
 		iscsit_remove_cmd_from_response_queue(cmd, conn);
 	}
+
+	if (conn && conn->conn_transport->iscsit_release_cmd)
+		conn->conn_transport->iscsit_release_cmd(conn, cmd);
 }
 
 void iscsit_free_cmd(struct iscsi_cmd *cmd, bool shutdown)

include/target/iscsi/iscsi_transport.h

@@ -24,6 +24,7 @@ struct iscsit_transport {
 	void (*iscsit_aborted_task)(struct iscsi_conn *, struct iscsi_cmd *);
 	int (*iscsit_xmit_pdu)(struct iscsi_conn *, struct iscsi_cmd *,
 			       struct iscsi_datain_req *, const void *, u32);
+	void (*iscsit_release_cmd)(struct iscsi_conn *, struct iscsi_cmd *);
 	enum target_prot_op (*iscsit_get_sup_prot_ops)(struct iscsi_conn *);
 };