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authorEric W. Biederman <ebiederm@xmission.com>2017-06-04 04:32:13 -0500
committerEric W. Biederman <ebiederm@xmission.com>2018-07-21 10:43:12 -0500
commit6883f81aac6f44e7df70a6af189b3689ff52cbfb (patch)
tree184e376d23aa5ea7321e22f23dd78a3c77c74a63 /include/linux/sched/signal.h
parent2c4704756cab7cfa031ada4dab361562f0e357c0 (diff)
pid: Implement PIDTYPE_TGID
Everywhere except in the pid array we distinguish between a tasks pid and a tasks tgid (thread group id). Even in the enumeration we want that distinction sometimes so we have added __PIDTYPE_TGID. With leader_pid we almost have an implementation of PIDTYPE_TGID in struct signal_struct. Add PIDTYPE_TGID as a first class member of the pid_type enumeration and into the pids array. Then remove the __PIDTYPE_TGID special case and the leader_pid in signal_struct. The net size increase is just an extra pointer added to struct pid and an extra pair of pointers of an hlist_node added to task_struct. The effect on code maintenance is the removal of a number of special cases today and the potential to remove many more special cases as PIDTYPE_TGID gets used to it's fullest. The long term potential is allowing zombie thread group leaders to exit, which will remove a lot more special cases in the code. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Diffstat (limited to 'include/linux/sched/signal.h')
-rw-r--r--include/linux/sched/signal.h5
1 files changed, 2 insertions, 3 deletions
diff --git a/include/linux/sched/signal.h b/include/linux/sched/signal.h
index 2dcded16eb1e..ee30a5ba475f 100644
--- a/include/linux/sched/signal.h
+++ b/include/linux/sched/signal.h
@@ -147,7 +147,6 @@ struct signal_struct {
#endif
/* PID/PID hash table linkage. */
- struct pid *leader_pid;
struct pid *pids[PIDTYPE_MAX];
#ifdef CONFIG_NO_HZ_FULL
@@ -571,7 +570,7 @@ struct pid *task_pid_type(struct task_struct *task, enum pid_type type)
static inline struct pid *task_tgid(struct task_struct *task)
{
- return task->signal->leader_pid;
+ return task->signal->pids[PIDTYPE_TGID];
}
/*
@@ -607,7 +606,7 @@ static inline bool thread_group_leader(struct task_struct *p)
*/
static inline bool has_group_leader_pid(struct task_struct *p)
{
- return task_pid(p) == p->signal->leader_pid;
+ return task_pid(p) == task_tgid(p);
}
static inline