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Subject: Re: [PATCH v4 1/2] pid: Replace pid bitmap implementation with IDR
 API
From: Rik van Riel <riel@surriel.com>
To: Gargi Sharma <gs051095@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>,
        Andrew Morton <akpm@linux-foundation.org>,
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        "Eric W. Biederman" <ebiederm@xmission.com>,
        Christoph Hellwig <hch@infradead.org>
Date: Tue, 10 Oct 2017 13:51:06 -0400
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On Tue, 2017-10-10 at 17:11 +0100, Gargi Sharma wrote:
>=20
> I have listed down the code for both idr_for_each and
> idr_for_each_entry.
> IMHO idr_for_each_entry is easier to read, but YMMV. :)
>=20
> void kill_task(int id, void *ptr, void *data)
> {
> =C2=A0=C2=A0=C2=A0=C2=A0struct *pid =3D ptr;
> =C2=A0=C2=A0=C2=A0=C2=A0struct task_struct *task =3D pid_task(pid, PIDTYP=
E_PID);
> =C2=A0=C2=A0=C2=A0=C2=A0if (task && !__fatal_signal_pending(task))
> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0send_sig_info(SIGKI=
LL, SEND_SIG_FORCED, task);
> }
>=20
> rcu_read_unlock();
> idr_for_each(&pid_ns->idr, &kill_task, NULL);
> rcu_read_unlock();

It also looks like idr_for_each has no easy
way to skip over PID 1, like you can do with
idr_for_each_entry_continue().

I agree with you, the code below is easier to
read than the code above.

> idr_for_each_entry_continue(&pid_ns->idr, pid, nr) {
> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0task =3D pid_=
task(pid, PIDTYPE_PID);
> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0if (task && !=
__fatal_signal_pending(task))
> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0=C2=A0send_sig_info(SIGKILL, SEND_SIG_FORCED, task);
> }
>=20
> Thanks!
> Gargi
> >=20
> > --
> > All rights reversed
>=20
>=20
--=20
All rights reversed
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