From e713d0dab21a68500720e222fa02567fc7dfb14b Mon Sep 17 00:00:00 2001 From: Sukadev Bhattiprolu Date: Thu, 10 May 2007 22:22:58 -0700 Subject: [PATCH] attach_pid() with struct pid parameter attach_pid() currently takes a pid_t and then uses find_pid() to find the corresponding struct pid. Sometimes we already have the struct pid. We can then skip find_pid() if attach_pid() were to take a struct pid parameter. Signed-off-by: Sukadev Bhattiprolu Cc: Cedric Le Goater Cc: Dave Hansen Cc: Serge Hallyn Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/exec.c | 2 +- include/linux/pid.h | 3 +-- kernel/exit.c | 4 ++-- kernel/fork.c | 11 +++++++---- kernel/pid.c | 9 ++++++--- kernel/sys.c | 2 +- 6 files changed, 18 insertions(+), 13 deletions(-) diff --git a/fs/exec.c b/fs/exec.c index 1ba85c7fc6af..2255dc72deef 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -702,7 +702,7 @@ static int de_thread(struct task_struct *tsk) */ detach_pid(tsk, PIDTYPE_PID); tsk->pid = leader->pid; - attach_pid(tsk, PIDTYPE_PID, tsk->pid); + attach_pid(tsk, PIDTYPE_PID, find_pid(tsk->pid)); transfer_pid(leader, tsk, PIDTYPE_PGID); transfer_pid(leader, tsk, PIDTYPE_SID); list_replace_rcu(&leader->tasks, &tsk->tasks); diff --git a/include/linux/pid.h b/include/linux/pid.h index 2ac27f9997dd..33d343880d89 100644 --- a/include/linux/pid.h +++ b/include/linux/pid.h @@ -76,8 +76,7 @@ extern struct pid *get_task_pid(struct task_struct *task, enum pid_type type); * write-held. */ extern int FASTCALL(attach_pid(struct task_struct *task, - enum pid_type type, int nr)); - + enum pid_type type, struct pid *pid)); 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)); diff --git a/kernel/exit.c b/kernel/exit.c index 7a5fd77f8fb0..e93691e9b325 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -302,12 +302,12 @@ void __set_special_pids(pid_t session, pid_t pgrp) if (process_session(curr) != session) { detach_pid(curr, PIDTYPE_SID); set_signal_session(curr->signal, session); - attach_pid(curr, PIDTYPE_SID, session); + attach_pid(curr, PIDTYPE_SID, find_pid(session)); } if (process_group(curr) != pgrp) { detach_pid(curr, PIDTYPE_PGID); curr->signal->pgrp = pgrp; - attach_pid(curr, PIDTYPE_PGID, pgrp); + attach_pid(curr, PIDTYPE_PGID, find_pid(pgrp)); } } diff --git a/kernel/fork.c b/kernel/fork.c index da92e01aba6b..6031800c94cf 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -1249,16 +1249,19 @@ static struct task_struct *copy_process(unsigned long clone_flags, __ptrace_link(p, current->parent); if (thread_group_leader(p)) { + pid_t pgid = process_group(current); + pid_t sid = process_session(current); + p->signal->tty = current->signal->tty; - p->signal->pgrp = process_group(current); + p->signal->pgrp = pgid; set_signal_session(p->signal, process_session(current)); - attach_pid(p, PIDTYPE_PGID, process_group(p)); - attach_pid(p, PIDTYPE_SID, process_session(p)); + attach_pid(p, PIDTYPE_PGID, find_pid(pgid)); + attach_pid(p, PIDTYPE_SID, find_pid(sid)); list_add_tail_rcu(&p->tasks, &init_task.tasks); __get_cpu_var(process_counts)++; } - attach_pid(p, PIDTYPE_PID, p->pid); + attach_pid(p, PIDTYPE_PID, find_pid(p->pid)); nr_threads++; } diff --git a/kernel/pid.c b/kernel/pid.c index d3ad724afa83..d76f59326bd4 100644 --- a/kernel/pid.c +++ b/kernel/pid.c @@ -247,13 +247,16 @@ struct pid * fastcall find_pid(int nr) } EXPORT_SYMBOL_GPL(find_pid); -int fastcall attach_pid(struct task_struct *task, enum pid_type type, int nr) +/* + * attach_pid() must be called with the tasklist_lock write-held. + */ +int fastcall attach_pid(struct task_struct *task, enum pid_type type, + struct pid *pid) { struct pid_link *link; - struct pid *pid; link = &task->pids[type]; - link->pid = pid = find_pid(nr); + link->pid = pid; hlist_add_head_rcu(&link->node, &pid->tasks[type]); return 0; diff --git a/kernel/sys.c b/kernel/sys.c index df4c3a8f5df9..872271ccc384 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -1488,7 +1488,7 @@ asmlinkage long sys_setpgid(pid_t pid, pid_t pgid) if (process_group(p) != pgid) { detach_pid(p, PIDTYPE_PGID); p->signal->pgrp = pgid; - attach_pid(p, PIDTYPE_PGID, pgid); + attach_pid(p, PIDTYPE_PGID, find_pid(pgid)); } err = 0;