ipc_seq_pid_ns   1290 ipc/msg.c      	struct pid_namespace *pid_ns = ipc_seq_pid_ns(s);
ipc_seq_pid_ns   1741 ipc/shm.c      	struct pid_namespace *pid_ns = ipc_seq_pid_ns(s);
ipc_seq_pid_ns    119 ipc/util.h     struct pid_namespace *ipc_seq_pid_ns(struct seq_file *);