[PATCH 3.10 138/143] kernel/fork.c:copy_process(): unify CLONE_THREAD-or-thread_group_leader code

From: Greg Kroah-Hartman
Date: Fri Oct 03 2014 - 18:30:18 EST


3.10-stable review patch. If anyone has any objections, please let me know.

------------------

From: Oleg Nesterov <oleg@xxxxxxxxxx>

commit 80628ca06c5d42929de6bc22c0a41589a834d151 upstream.

Cleanup and preparation for the next changes.

Move the "if (clone_flags & CLONE_THREAD)" code down under "if
(likely(p->pid))" and turn it into into the "else" branch. This makes the
process/thread initialization more symmetrical and removes one check.

Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxx>
Cc: Pavel Emelyanov <xemul@xxxxxxxxxxxxx>
Cc: Sergey Dyasly <dserrg@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Li Zefan <lizefan@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
kernel/fork.c | 15 +++++++--------
1 file changed, 7 insertions(+), 8 deletions(-)

--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1448,14 +1448,6 @@ static struct task_struct *copy_process(
goto bad_fork_free_pid;
}

- if (clone_flags & CLONE_THREAD) {
- current->signal->nr_threads++;
- atomic_inc(&current->signal->live);
- atomic_inc(&current->signal->sigcnt);
- p->group_leader = current->group_leader;
- list_add_tail_rcu(&p->thread_group, &p->group_leader->thread_group);
- }
-
if (likely(p->pid)) {
ptrace_init_task(p, (clone_flags & CLONE_PTRACE) || trace);

@@ -1472,6 +1464,13 @@ static struct task_struct *copy_process(
list_add_tail(&p->sibling, &p->real_parent->children);
list_add_tail_rcu(&p->tasks, &init_task.tasks);
__this_cpu_inc(process_counts);
+ } else {
+ current->signal->nr_threads++;
+ atomic_inc(&current->signal->live);
+ atomic_inc(&current->signal->sigcnt);
+ p->group_leader = current->group_leader;
+ list_add_tail_rcu(&p->thread_group,
+ &p->group_leader->thread_group);
}
attach_pid(p, PIDTYPE_PID, pid);
nr_threads++;


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