Commit 5cd20455 authored by Pavel Emelyanov's avatar Pavel Emelyanov Committed by Linus Torvalds
Browse files

Deprecate find_task_by_pid() 



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: default avatarPavel Emelyanov <xemul@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: default avatarSukadev Bhattiprolu <sukadev@us.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent cb41d6d0

Documentation/feature-removal-schedule.txt

+18 −0
Original line number Diff line number Diff line
@@ -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.

include/linux/sched.h

+4 −1
Original line number Diff line number Diff line
@@ -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);

init/main.c

+1 −1
Original line number Diff line number Diff line
@@ -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();



	/*

kernel/kthread.c

+1 −1
Original line number Diff line number Diff line
@@ -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.

kernel/pid.c

+0 −6
Original line number Diff line number Diff line
@@ -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,

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