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Re: [PATCH 8/15] Helpers to find the task by its numerical ids [message #15332 is a reply to message #15324]

Fri, 27 July 2007 06:43

Pavel Emelianov
Messages: 1149
Registered: September 2006

Senior Member

Dave Hansen wrote:
> On Thu, 2007-07-26 at 18:51 +0400, Pavel Emelyanov wrote:
>> +extern struct task_struct *find_task_by_pid_type_ns(int type, int pid,
>> + struct pid_namespace *ns);
>> +
>> +#define find_task_by_pid_ns(nr, ns) \
>> + find_task_by_pid_type_ns(PIDTYPE_PID, nr, ns)
>> +#define find_task_by_pid_type(type, nr) \
>> + find_task_by_pid_type_ns(type, nr, &init_pid_ns)
>> +#define find_task_by_pid(nr) \
>> + find_task_by_pid_type(PIDTYPE_PID, nr)
>> +
>> extern void __set_special_pids(pid_t session, pid_t pgrp);
>
> Do these _have_ to be macros?

No, but why not?
I can make them static inline functions, but why are macros that bad?

>> /* per-UID process charging. */
>> diff -upr linux-2.6.23-rc1-mm1.orig/kernel/pid.c linux-2.6.23-rc1-mm1-7/kernel/pid.c
>> --- linux-2.6.23-rc1-mm1.orig/kernel/pid.c 2007-07-26 16:34:45.000000000 +0400
>> +++ linux-2.6.23-rc1-mm1-7/kernel/pid.c 2007-07-26 16:36:37.000000000 +0400
>> @@ -204,19 +221,20 @@ static void delayed_put_pid(struct rcu_h
>> goto out;
>> }
>>
>> -struct pid * fastcall find_pid(int nr)
>> +struct pid * fastcall find_pid_ns(int nr, struct pid_namespace *ns)
>> {
>> struct hlist_node *elem;
>> - struct pid *pid;
>> + struct upid *pnr;
>> +
>> + hlist_for_each_entry_rcu(pnr, elem,
>> + &pid_hash[pid_hashfn(nr, ns)], pid_chain)
>> + if (pnr->nr == nr && pnr->ns == ns)
>> + return container_of(pnr, struct pid,
>> + numbers[ns->level]);
>
> Do we do this loop anywhere else? Should we have a for_each_pid() that
> makes this a little less messy?

No. Iteration over the hash chain happens here only.

>> - hlist_for_each_entry_rcu(pid, elem,
>> - &pid_hash[pid_hashfn(nr)], pid_chain) {
>> - if (pid->nr == nr)
>> - return pid;
>> - }
>> return NULL;
>> }
>> -EXPORT_SYMBOL_GPL(find_pid);
>> +EXPORT_SYMBOL_GPL(find_pid_ns);
>>
>> /*
>> * attach_pid() must be called with the tasklist_lock write-held.
>> @@ -318,12 +355,13 @@ struct task_struct * fastcall pid_task(s
>> /*
>> * Must be called under rcu_read_lock() or with tasklist_lock read-held.
>> */
>> -struct task_struct *find_task_by_pid_type(int type, int nr)
>> +struct task_struct *find_task_by_pid_type_ns(int type, int nr,
>> + struct pid_namespace *ns)
>> {
>> - return pid_task(find_pid(nr), type);
>> + return pid_task(find_pid_ns(nr, ns), type);
>> }
>>
>> -EXPORT_SYMBOL(find_task_by_pid_type);
>> +EXPORT_SYMBOL(find_task_by_pid_type_ns);
>>
>> struct pid *get_task_pid(struct task_struct *task, enum pid_type type)
>> {
>> @@ -342,7 +426,7 @@ struct pid *find_get_pid(pid_t nr)
>> struct pid *pid;
>>
>> rcu_read_lock();
>> - pid = get_pid(find_pid(nr));
>> + pid = get_pid(find_vpid(nr));
>> rcu_read_unlock();
>
> OK, I think this is really confusing. If find_get_pid() finds vpids,
> should we not call it find_get_vpid()?

I'd better make it find_get_pid_ns() with two arguments and made a couple
of macros (or static inlines) for global search and local search.

> -- Dave
>
>

Thanks,
Pavel

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[Message index]

		[RFC][PATCH 0/15] Pid namespaces By: Pavel Emelianov on Thu, 26 July 2007 14:45
		[PATCH 1/15] Move exit_task_namespaces() By: Pavel Emelianov on Thu, 26 July 2007 14:46
		Re: [PATCH 1/15] Move exit_task_namespaces() By: Oleg Nesterov on Thu, 26 July 2007 16:47
		Re: [PATCH 1/15] Move exit_task_namespaces() By: Oleg Nesterov on Fri, 27 July 2007 08:07
		Re: [PATCH 1/15] Move exit_task_namespaces() By: Pavel Emelianov on Fri, 27 July 2007 08:24
		Re: [PATCH 1/15] Move exit_task_namespaces() By: Oleg Nesterov on Fri, 27 July 2007 08:35
		Re: [PATCH 1/15] Move exit_task_namespaces() By: Pavel Emelianov on Fri, 27 July 2007 08:37
		Re: [PATCH 1/15] Move exit_task_namespaces() By: dev on Thu, 26 July 2007 16:59
		Re: [PATCH 1/15] Move exit_task_namespaces() By: Dave Hansen on Thu, 26 July 2007 16:10
		Re: [PATCH 1/15] Move exit_task_namespaces() By: xemul on Fri, 27 July 2007 06:38
		Re: [PATCH 1/15] Move exit_task_namespaces() By: Oleg Nesterov on Thu, 02 August 2007 16:18
		Re: [PATCH 1/15] Move exit_task_namespaces() By: Pavel Emelianov on Mon, 06 August 2007 08:00
		Re: [PATCH 1/15] Move exit_task_namespaces() By: Oleg Nesterov on Mon, 06 August 2007 09:54
		Re: [PATCH 1/15] Move exit_task_namespaces() By: Pavel Emelianov on Mon, 06 August 2007 09:58
		Re: [PATCH 1/15] Move exit_task_namespaces() By: Oleg Nesterov on Mon, 06 August 2007 10:38
		Re: [PATCH 1/15] Move exit_task_namespaces() By: Pavel Emelianov on Mon, 06 August 2007 11:21
		Re: [PATCH 1/15] Move exit_task_namespaces() By: Oleg Nesterov on Mon, 06 August 2007 12:52
		Re: [PATCH 1/15] Move exit_task_namespaces() By: Pavel Emelianov on Mon, 06 August 2007 13:38
		Re: [PATCH 1/15] Move exit_task_namespaces() By: Pavel Emelianov on Mon, 06 August 2007 11:29
		Re: [PATCH 1/15] Move exit_task_namespaces() By: Oleg Nesterov on Mon, 06 August 2007 12:48
		Re: [PATCH 1/15] Move exit_task_namespaces() By: Pavel Emelianov on Mon, 06 August 2007 13:36
		Re: [PATCH 1/15] Move exit_task_namespaces() By: Oleg Nesterov on Mon, 06 August 2007 13:55
		[PATCH 2/15] Introduce MS_KERNMOUNT flag By: Pavel Emelianov on Thu, 26 July 2007 14:47
		[PATCH 3/15] kern_siginfo helper By: Pavel Emelianov on Thu, 26 July 2007 14:48
		Re: [PATCH 3/15] kern_siginfo helper By: Oleg Nesterov on Sun, 29 July 2007 11:40
		Re: [PATCH 3/15] kern_siginfo helper By: Pavel Emelianov on Mon, 30 July 2007 06:07
		Re: [PATCH 3/15] kern_siginfo helper By: Sukadev Bhattiprolu on Tue, 31 July 2007 00:21
		[PATCH 4/15] Make proc_flust_task() flush entries from multiple proc trees By: Pavel Emelianov on Thu, 26 July 2007 14:48
		[PATCH 5/15] Introduce struct upid By: Pavel Emelianov on Thu, 26 July 2007 14:49
		Re: [PATCH 5/15] Introduce struct upid By: Oleg Nesterov on Sun, 29 July 2007 09:50
		Re: [PATCH 5/15] Introduce struct upid By: Pavel Emelianov on Mon, 30 July 2007 05:58
		[PATCH 6/15] Make alloc_pid(), free_pid() and put_pid() work with struct upid By: Pavel Emelianov on Thu, 26 July 2007 14:50
		Re: [PATCH 6/15] Make alloc_pid(), free_pid() and put_pid() work with struct upid By: Oleg Nesterov on Sun, 29 July 2007 10:14
		Re: [PATCH 6/15] Make alloc_pid(), free_pid() and put_pid() work with struct upid By: Pavel Emelianov on Mon, 30 July 2007 06:03
		[PATCH 7/15] Helpers to obtain pid numbers By: Pavel Emelianov on Thu, 26 July 2007 14:51
		Re: [PATCH 7/15] Helpers to obtain pid numbers By: Dave Hansen on Thu, 26 July 2007 19:03
		Re: [PATCH 7/15] Helpers to obtain pid numbers By: Pavel Emelianov on Fri, 27 July 2007 06:40
		Re: [PATCH 7/15] Helpers to obtain pid numbers By: Oleg Nesterov on Sun, 29 July 2007 12:08
		Re: [PATCH 7/15] Helpers to obtain pid numbers By: Pavel Emelianov on Mon, 30 July 2007 06:11
		[PATCH 8/15] Helpers to find the task by its numerical ids By: Pavel Emelianov on Thu, 26 July 2007 14:51
		Re: [PATCH 8/15] Helpers to find the task by its numerical ids By: Dave Hansen on Thu, 26 July 2007 19:05
		Re: [PATCH 8/15] Helpers to find the task by its numerical ids By: Pavel Emelianov on Fri, 27 July 2007 06:43
		Re: [PATCH 8/15] Helpers to find the task by its numerical ids By: Oleg Nesterov on Sun, 29 July 2007 12:39
		Re: [PATCH 8/15] Helpers to find the task by its numerical ids By: Pavel Emelianov on Mon, 30 July 2007 06:15
		[PATCH 9/15] Move alloc_pid() after the namespace is cloned By: Pavel Emelianov on Thu, 26 July 2007 14:52
		Re: [PATCH 9/15] Move alloc_pid() after the namespace is cloned By: Oleg Nesterov on Fri, 27 July 2007 15:10
		Re: [PATCH 9/15] Move alloc_pid() after the namespace is cloned By: Pavel Emelianov on Mon, 30 July 2007 06:17
		Re: [PATCH 9/15] Move alloc_pid() after the namespace is cloned By: Sukadev Bhattiprolu on Mon, 30 July 2007 23:43
		Re: [PATCH 9/15] Move alloc_pid() after the namespace is cloned By: Sukadev Bhattiprolu on Tue, 31 July 2007 05:49
		[PATCH 10/15] Make each namespace has its own proc tree By: Pavel Emelianov on Thu, 26 July 2007 14:54
		Re: [PATCH 10/15] Make each namespace has its own proc tree By: Oleg Nesterov on Sun, 29 July 2007 15:56
		Re: [PATCH 10/15] Make each namespace has its own proc tree By: Oleg Nesterov on Sun, 29 July 2007 17:02
		Re: [PATCH 10/15] Make each namespace has its own proc tree By: Pavel Emelianov on Mon, 30 July 2007 06:45
		Re: [PATCH 10/15] Make each namespace has its own proc tree By: Pavel Emelianov on Mon, 30 July 2007 06:43
		[PATCH 11/15] Signal semantics By: Pavel Emelianov on Thu, 26 July 2007 14:55
		Re: [PATCH 11/15] Signal semantics By: Oleg Nesterov on Fri, 27 July 2007 12:30
		Re: [PATCH 11/15] Signal semantics By: Pavel Emelianov on Fri, 27 July 2007 13:38
		Re: [PATCH 11/15] Signal semantics By: serue on Fri, 27 July 2007 19:59
		Re: [PATCH 11/15] Signal semantics By: Sukadev Bhattiprolu on Fri, 27 July 2007 20:23
		Re: [PATCH 11/15] Signal semantics By: Pavel Emelianov on Mon, 30 July 2007 09:34
		Re: [PATCH 11/15] Signal semantics By: Pavel Emelianov on Mon, 30 July 2007 09:31
		Re: [PATCH 11/15] Signal semantics By: serue on Wed, 01 August 2007 16:13
		Re: [PATCH 11/15] Signal semantics By: dev on Thu, 02 August 2007 08:35
		Re: [PATCH 11/15] Signal semantics By: serue on Thu, 02 August 2007 20:09
		Re: [PATCH 11/15] Signal semantics By: Oleg Nesterov on Sun, 29 July 2007 11:23
		[PATCH 12/15] Miscelaneous stuff for pid namespaces By: Pavel Emelianov on Thu, 26 July 2007 14:56
		Re: [PATCH 12/15] Miscelaneous stuff for pid namespaces By: Pavel Emelianov on Fri, 27 July 2007 06:53
		Re: [PATCH 12/15] Miscelaneous stuff for pid namespaces By: Sukadev Bhattiprolu on Fri, 27 July 2007 06:22
		[PATCH 13/15] Clone the pid namespace By: Pavel Emelianov on Thu, 26 July 2007 14:56
		[PATCH 14/15] Destroy pid namespace on init's death By: Pavel Emelianov on Thu, 26 July 2007 14:57
		Re: [PATCH 14/15] Destroy pid namespace on init's death By: Oleg Nesterov on Sun, 29 July 2007 10:39
		Re: [PATCH 14/15] Destroy pid namespace on init's death By: Pavel Emelianov on Mon, 30 July 2007 11:56
		Re: [PATCH 14/15] Destroy pid namespace on init's death By: Oleg Nesterov on Mon, 30 July 2007 15:44
		Re: [PATCH 14/15] Destroy pid namespace on init's death By: Oleg Nesterov on Tue, 31 July 2007 09:07
		Re: [PATCH 14/15] Destroy pid namespace on init's death By: Sukadev Bhattiprolu on Wed, 01 August 2007 06:16
		Re: [PATCH 14/15] Destroy pid namespace on init's death By: Dave Hansen on Wed, 01 August 2007 16:00
		Re: [PATCH 14/15] Destroy pid namespace on init's death By: Oleg Nesterov on Wed, 01 August 2007 19:51
		Re: [PATCH 14/15] Destroy pid namespace on init's death By: dev on Thu, 02 August 2007 08:37
		Re: [PATCH 14/15] Destroy pid namespace on init's death By: Oleg Nesterov on Thu, 02 August 2007 16:08
		Re: [PATCH 14/15] Destroy pid namespace on init's death By: Oleg Nesterov on Thu, 02 August 2007 17:08
		Re: [PATCH 14/15] Destroy pid namespace on init's death By: Sukadev Bhattiprolu on Fri, 03 August 2007 06:22
		Re: [PATCH 14/15] Destroy pid namespace on init's death By: Oleg Nesterov on Fri, 03 August 2007 10:55
		Re: [PATCH 14/15] Destroy pid namespace on init's death By: Sukadev Bhattiprolu on Thu, 02 August 2007 07:37
		Re: [PATCH 14/15] Destroy pid namespace on init's death By: Oleg Nesterov on Wed, 01 August 2007 19:48
		Re: [PATCH 14/15] Destroy pid namespace on init's death By: Sukadev Bhattiprolu on Thu, 02 August 2007 07:29
		Re: [PATCH 14/15] Destroy pid namespace on init's death By: Oleg Nesterov on Thu, 02 August 2007 15:39
		Re: [PATCH 14/15] Destroy pid namespace on init's death By: Sukadev Bhattiprolu on Thu, 02 August 2007 17:20
		Re: [PATCH 14/15] Destroy pid namespace on init's death By: Oleg Nesterov on Thu, 02 August 2007 17:29
		Re: [PATCH 14/15] Destroy pid namespace on init's death By: Sukadev Bhattiprolu on Thu, 02 August 2007 18:36
		Re: [PATCH 14/15] Destroy pid namespace on init's death By: Oleg Nesterov on Thu, 02 August 2007 18:49
		Re: [PATCH 14/15] Destroy pid namespace on init's death By: serue on Thu, 02 August 2007 19:13
		Re: [PATCH 14/15] Destroy pid namespace on init's death By: Sukadev Bhattiprolu on Fri, 03 August 2007 21:36
		[PATCH 15/15] Hooks over the code to show correct values to user By: Pavel Emelianov on Thu, 26 July 2007 14:58
		Re: [PATCH 15/15] Hooks over the code to show correct values to user By: Sukadev Bhattiprolu on Fri, 27 July 2007 05:57
		Re: [PATCH 15/15] Hooks over the code to show correct values to user By: Pavel Emelianov on Fri, 27 July 2007 06:44
		Re: [PATCH 15/15] Hooks over the code to show correct values to user By: Oleg Nesterov on Sun, 29 July 2007 14:29
		Re: [PATCH 15/15] Hooks over the code to show correct values to user By: Pavel Emelianov on Mon, 30 July 2007 06:49
		Re: [PATCH 15/15] Hooks over the code to show correct values to user By: Oleg Nesterov on Tue, 31 July 2007 10:04
		Re: [RFC][PATCH 0/15] Pid namespaces By: Sukadev Bhattiprolu on Fri, 27 July 2007 04:22
		Re: [RFC][PATCH 0/15] Pid namespaces By: Sukadev Bhattiprolu on Fri, 27 July 2007 06:08
		Re: [RFC][PATCH 0/15] Pid namespaces By: Pavel Emelianov on Fri, 27 July 2007 06:47

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