From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0D789C2BA1A for ; Wed, 8 Apr 2020 16:28:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DE7F620784 for ; Wed, 8 Apr 2020 16:28:07 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="ZjU7ucIt" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730324AbgDHQ2H (ORCPT ); Wed, 8 Apr 2020 12:28:07 -0400 Received: from us-smtp-1.mimecast.com ([205.139.110.61]:42378 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726846AbgDHQ2F (ORCPT ); Wed, 8 Apr 2020 12:28:05 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1586363284; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=E/L4ALyvrKq9jt7009jD8vn4VfcLT3lIG5y3VVV2B/M=; b=ZjU7ucItGpBo3N00IKtG0cHIqSxG+m83wJa6eieQYoERxh/avptxrx2OI8tfZAToD4gBJx mCzXejt1ppTFDypfd/m9Mu+GWeY8+jHbvx/RsOVP/Hud+981Azmp0NymVyqIxvdQemU5eO 4/MweIb5DE9bvkgBmP6IdV7kuBeFIWk= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-140--NMhJJ6tPLq1BtIPxvulPQ-1; Wed, 08 Apr 2020 12:28:00 -0400 X-MC-Unique: -NMhJJ6tPLq1BtIPxvulPQ-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id BFECDDB60; Wed, 8 Apr 2020 16:27:58 +0000 (UTC) Received: from gondolin (ovpn-113-103.ams2.redhat.com [10.36.113.103]) by smtp.corp.redhat.com (Postfix) with ESMTP id 240DF5DA7C; Wed, 8 Apr 2020 16:27:52 +0000 (UTC) Date: Wed, 8 Apr 2020 18:27:50 +0200 From: Cornelia Huck To: Tony Krowiak Cc: linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, freude@linux.ibm.com, borntraeger@de.ibm.com, mjrosato@linux.ibm.com, pmorel@linux.ibm.com, pasic@linux.ibm.com, alex.williamson@redhat.com, kwankhede@nvidia.com, jjherne@linux.ibm.com, fiuczy@linux.ibm.com Subject: Re: [PATCH v7 01/15] s390/vfio-ap: store queue struct in hash table for quick access Message-ID: <20200408182750.6d9443f6.cohuck@redhat.com> In-Reply-To: References: <20200407192015.19887-1-akrowiak@linux.ibm.com> <20200407192015.19887-2-akrowiak@linux.ibm.com> <20200408124801.2d61bc5b.cohuck@redhat.com> Organization: Red Hat GmbH MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 8 Apr 2020 11:38:07 -0400 Tony Krowiak wrote: > On 4/8/20 6:48 AM, Cornelia Huck wrote: > > On Tue, 7 Apr 2020 15:20:01 -0400 > > Tony Krowiak wrote: > > =20 > >> Rather than looping over potentially 65535 objects, let's store the > >> structures for caching information about queue devices bound to the > >> vfio_ap device driver in a hash table keyed by APQN. =20 > > This also looks like a nice code simplification. > > =20 > >> Signed-off-by: Tony Krowiak > >> --- > >> drivers/s390/crypto/vfio_ap_drv.c | 28 +++------ > >> drivers/s390/crypto/vfio_ap_ops.c | 90 ++++++++++++++-----------= -- > >> drivers/s390/crypto/vfio_ap_private.h | 10 ++- > >> 3 files changed, 60 insertions(+), 68 deletions(-) > >> =20 > > (...) > >> - */ > >> -static struct vfio_ap_queue *vfio_ap_get_queue( > >> - struct ap_matrix_mdev *matrix_mdev, > >> - int apqn) > >> +struct vfio_ap_queue *vfio_ap_get_queue(unsigned long apqn) > >> { > >> struct vfio_ap_queue *q; > >> - struct device *dev; > >> - > >> - if (!test_bit_inv(AP_QID_CARD(apqn), matrix_mdev->matrix.apm)) > >> - return NULL; > >> - if (!test_bit_inv(AP_QID_QUEUE(apqn), matrix_mdev->matrix.aqm)) > >> - return NULL; =20 > > These were just optimizations and therefore can be dropped now? =20 >=20 > The purpose of this function has changed from its previous incarnation. > This function was originally called from the handle_pqap() function and > served two purposes: It retrieved the struct vfio_ap_queue as driver data > and linked the matrix_mdev to the=C2=A0 vfio_ap_queue. The linking of the > matrix_mdev and the vfio_ap_queue are now done when queue devices > are probed and when adapters and domains are assigned; so now, the > handle_pqap() function calls this function to retrieve both the > vfio_ap_queue as well as the matrix_mdev to which it is linked.=20 > Consequently, > the above code is no longer needed. Thanks for the explanation, that makes sense. >=20 > > =20 > >> - > >> - dev =3D driver_find_device(&matrix_dev->vfio_ap_drv->driver, NULL, > >> - &apqn, match_apqn); > >> - if (!dev) > >> - return NULL; > >> - q =3D dev_get_drvdata(dev); > >> - q->matrix_mdev =3D matrix_mdev; > >> - put_device(dev); > >> =20 > >> - return q; > >> + hash_for_each_possible(matrix_dev->qtable, q, qnode, apqn) { > >> + if (q && (apqn =3D=3D q->apqn)) > >> + return q; > >> + } =20 > > Do we need any serialization here? Previously, the driver core made > > sure we could get a reference only if the device was still registered; > > not sure if we need any further guarantees now. =20 >=20 > The vfio_ap_queue structs are created when the queue device is > probed and removed when the queue device is removed. Ok, so anything further is not needed. >=20 > > =20 > >> + > >> + return NULL; > >> } > >> =20 > >> /** =20 > > (...) > > =20 >=20 Looks good to me, then. With vfio_ap_get_queue made static and the kerneldoc restored/updated: Reviewed-by: Cornelia Huck