[PATCH 3.4 071/177] kernel/fork.c:copy_process(): unify CLONE_THREAD-or-thread_group_leader code

[lizf]

From: Oleg Nesterov <oleg@xxxxxxxxxx>

3.4.106-rc1 review patch.  If anyone has any objections, please let me know.

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


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>
Signed-off-by: Zefan Li <lizefan@xxxxxxxxxx>
---
 kernel/fork.c | 15 +++++++--------
 1 file changed, 7 insertions(+), 8 deletions(-)

diff --git a/kernel/fork.c b/kernel/fork.c
index 878dcb2..0a189c0 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1412,14 +1412,6 @@ static struct task_struct *copy_process(unsigned long clone_flags,
 		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);
 
@@ -1434,6 +1426,13 @@ static struct task_struct *copy_process(unsigned long clone_flags,
 			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++;
-- 
1.9.1

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