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 <sukadev@us.ibm.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Cc: Serge Hallyn <serue@us.ibm.com>
Cc: <containers@lists.osdl.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/exec.c b/fs/exec.c
index 1ba85c7..2255dc7 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -702,7 +702,7 @@
*/
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 2ac27f9..33d3438 100644
--- a/include/linux/pid.h
+++ b/include/linux/pid.h
@@ -76,8 +76,7 @@
* 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 7a5fd77..e93691e 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -302,12 +302,12 @@
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 da92e01..6031800 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1249,16 +1249,19 @@
__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 d3ad724..d76f593 100644
--- a/kernel/pid.c
+++ b/kernel/pid.c
@@ -247,13 +247,16 @@
}
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 df4c3a8..872271c 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -1488,7 +1488,7 @@
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;