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Deprecate find_task_by_pid()

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There are some places that are known to operate on tasks'
global pids only:

* the rest_init() call (called on boot)
* the kgdb's getthread
* the create_kthread() (since the kthread is run in init ns)

So use the find_task_by_pid_ns(..., &init_pid_ns) there
and schedule the find_task_by_pid for removal.

[sukadev@us.ibm.com: Fix warning in kernel/pid.c]
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Pavel Emelyanov 2008-04-30 00:54:24 -07:00 committed by Linus Torvalds
parent cb41d6d068
commit 5cd204550b
5 changed files with 24 additions and 9 deletions
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18
Documentation/feature-removal-schedule.txt
View File

@ -138,6 +138,24 @@ Who: Kay Sievers <kay.sievers@suse.de>
---------------------------
What: find_task_by_pid
When: 2.6.26
Why: With pid namespaces, calling this funciton will return the
wrong task when called from inside a namespace.
The best way to save a task pid and find a task by this
pid later, is to find this task's struct pid pointer (or get
it directly from the task) and call pid_task() later.
If someone really needs to get a task by its pid_t, then
he most likely needs the find_task_by_vpid() to get the
task from the same namespace as the current task is in, but
this may be not so in general.
Who: Pavel Emelyanov <xemul@openvz.org>
---------------------------
What: ACPI procfs interface
When: July 2008
Why: ACPI sysfs conversion should be finished by January 2008.

5
include/linux/sched.h
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@ -1677,7 +1677,10 @@ extern struct pid_namespace init_pid_ns;
extern struct task_struct *find_task_by_pid_type_ns(int type, int pid,
struct pid_namespace *ns);
extern struct task_struct *find_task_by_pid(pid_t nr);
static inline struct task_struct *__deprecated find_task_by_pid(pid_t nr)
{
return find_task_by_pid_type_ns(PIDTYPE_PID, nr, &init_pid_ns);
}
extern struct task_struct *find_task_by_vpid(pid_t nr);
extern struct task_struct *find_task_by_pid_ns(pid_t nr,
struct pid_namespace *ns);

2
init/main.c
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@ -459,7 +459,7 @@ static void noinline __init_refok rest_init(void)
kernel_thread(kernel_init, NULL, CLONE_FS | CLONE_SIGHAND);
numa_default_policy();
pid = kernel_thread(kthreadd, NULL, CLONE_FS | CLONE_FILES);
kthreadd_task = find_task_by_pid(pid);
kthreadd_task = find_task_by_pid_ns(pid, &init_pid_ns);
unlock_kernel();
/*

2
kernel/kthread.c
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@ -98,7 +98,7 @@ static void create_kthread(struct kthread_create_info *create)
struct sched_param param = { .sched_priority = 0 };
wait_for_completion(&create->started);
read_lock(&tasklist_lock);
create->result = find_task_by_pid(pid);
create->result = find_task_by_pid_ns(pid, &init_pid_ns);
read_unlock(&tasklist_lock);
/*
* root may have changed our (kthreadd's) priority or CPU mask.

6
kernel/pid.c
View File

@ -381,12 +381,6 @@ struct task_struct *find_task_by_pid_type_ns(int type, int nr,
EXPORT_SYMBOL(find_task_by_pid_type_ns);
struct task_struct *find_task_by_pid(pid_t nr)
{
return find_task_by_pid_type_ns(PIDTYPE_PID, nr, &init_pid_ns);
}
EXPORT_SYMBOL(find_task_by_pid);
struct task_struct *find_task_by_vpid(pid_t vnr)
{
return find_task_by_pid_type_ns(PIDTYPE_PID, vnr,