linux-kernel - Re: [PATCH 3/4] pid.c: Replace pidhash lookup with idr

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Date:   Mon, 25 Sep 2017 23:14:45 +0530
From:   Gargi Sharma <gs051095@...il.com>
To:     Rik van Riel <riel@...riel.com>
Cc:     linux-kernel@...r.kernel.org, Julia Lawall <julia.lawall@...6.fr>,
        akpm@...ux-foundation.org, mingo@...nel.org,
        pasha.tatashin@...cle.com, ktkhai@...tuozzo.com,
        Oleg Nesterov <oleg@...hat.com>
Subject: Re: [PATCH 3/4] pid.c: Replace pidhash lookup with idr_get()

On Mon, Sep 25, 2017 at 6:50 PM, Rik van Riel <riel@...riel.com> wrote:
> On Mon, 2017-09-25 at 08:56 -0400, Gargi Sharma wrote:
>> pidhash is no longer required as all the functionalities
>> are present in the idr tree associated with the namespace.
>> nr can be looked up in the namespace by idr_get().
>>
>> Signed-off-by: Gargi Sharma <gs051095@...il.com>
>> ---
>>  kernel/pid.c | 10 +---------
>>  1 file changed, 1 insertion(+), 9 deletions(-)
>>
>> diff --git a/kernel/pid.c b/kernel/pid.c
>> index ea22e89..761a0c2 100644
>> --- a/kernel/pid.c
>> +++ b/kernel/pid.c
>> @@ -247,15 +247,7 @@ void disable_pid_allocation(struct pid_namespace
>> *ns)
>>
>>  struct pid *find_pid_ns(int nr, struct pid_namespace *ns)
>>  {
>> -     struct upid *pnr;
>> -
>> -     hlist_for_each_entry_rcu(pnr,
>> -                     &pid_hash[pid_hashfn(nr, ns)], pid_chain)
>> -             if (pnr->nr == nr && pnr->ns == ns)
>> -                     return container_of(pnr, struct pid,
>> -                                     numbers[ns->level]);
>> -
>> -     return NULL;
>> +     return idr_get(&ns->idr, &nr);
>>  }
>>  EXPORT_SYMBOL_GPL(find_pid_ns);
>
> Does this work if you call idr_find instead of idr_get?
>
> Then patch 2/4 would not be needed.
Yes, patch 2/4 can be dropped. I think this patch can be merged with
patch 4/4 where I remove pidhash, since this function is more or less
aimed at that too?

Thanks!
Gargi
>
> --
> All Rights Reversed.