pids: Move the pgrp and session pid pointers from task_struct to signal_struct
To access these fields the code always has to go to group leader so
going to signal struct is no loss and is actually a fundamental simplification.
This saves a little bit of memory by only allocating the pid pointer array
once instead of once for every thread, and even better this removes a
few potential races caused by the fact that group_leader can be changed
by de_thread, while signal_struct can not.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
diff --git a/init/init_task.c b/init/init_task.c
index 7914ffb..db12a61 100644
--- a/init/init_task.c
+++ b/init/init_task.c
@@ -34,6 +34,11 @@ static struct signal_struct init_signals = {
#endif
INIT_CPU_TIMERS(init_signals)
.leader_pid = &init_struct_pid,
+ .pids = {
+ [PIDTYPE_PID] = &init_struct_pid,
+ [PIDTYPE_PGID] = &init_struct_pid,
+ [PIDTYPE_SID] = &init_struct_pid,
+ },
INIT_PREV_CPUTIME(init_signals)
};
@@ -112,11 +117,7 @@ struct task_struct init_task
INIT_CPU_TIMERS(init_task)
.pi_lock = __RAW_SPIN_LOCK_UNLOCKED(init_task.pi_lock),
.timer_slack_ns = 50000, /* 50 usec default slack */
- .pids = {
- [PIDTYPE_PID] = INIT_PID_LINK(PIDTYPE_PID),
- [PIDTYPE_PGID] = INIT_PID_LINK(PIDTYPE_PGID),
- [PIDTYPE_SID] = INIT_PID_LINK(PIDTYPE_SID),
- },
+ .thread_pid = &init_struct_pid,
.thread_group = LIST_HEAD_INIT(init_task.thread_group),
.thread_node = LIST_HEAD_INIT(init_signals.thread_head),
#ifdef CONFIG_AUDITSYSCALL