From c18258c6f0848f97e85287f6271c511a092bb784 Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Wed, 27 Sep 2006 01:51:06 -0700 Subject: [PATCH] pid: Implement transfer_pid and use it to simplify de_thread In de_thread we move pids from one process to another, a rather ugly case. The function transfer_pid makes it clear what we are doing, and makes the action atomic. This is useful we ever want to atomically traverse the process group and session lists, in a rcu safe manner. Even if the atomic properties this change should be a win as transfer_pid should be less code to execute than executing both attach_pid and detach_pid, and this should make de_thread slightly smaller as only a single function call needs to be emitted. The only downside is that the code might be slower to execute as the odds are against transfer_pid being in cache. Signed-off-by: Eric W. Biederman Cc: Oleg Nesterov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/pid.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include/linux/pid.h') diff --git a/include/linux/pid.h b/include/linux/pid.h index 29960b03bef..93da7e2d9f3 100644 --- a/include/linux/pid.h +++ b/include/linux/pid.h @@ -76,6 +76,8 @@ extern int FASTCALL(attach_pid(struct task_struct *task, enum pid_type type, int nr)); extern void FASTCALL(detach_pid(struct task_struct *task, enum pid_type)); +extern void FASTCALL(transfer_pid(struct task_struct *old, + struct task_struct *new, enum pid_type)); /* * look up a PID in the hash table. Must be called with the tasklist_lock -- cgit v1.2.3