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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 15C43C19F2B for ; Thu, 28 Jul 2022 02:39:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237806AbiG1CjL (ORCPT ); Wed, 27 Jul 2022 22:39:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37408 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237718AbiG1CjI (ORCPT ); Wed, 27 Jul 2022 22:39:08 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 48DF35A8B8 for ; Wed, 27 Jul 2022 19:39:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1658975946; 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=5ymtTMNSBtFOhhmPgtQl8t8lfFLbeHZYYSYD2cD7gjw=; b=IGDwc89h5aJWj1EBZQWTY3a46nF+BN8BwCxay9u3ZNWYq0Kob0JyupLtJOWIrn3vEX0kzP UrjlgHpZWe5wDeQu7zWlGtoVXAXYuszAaTwq7DiqIliKHTF8gv46KDrXJsvR8qbZHAkB45 nkbcJi4dphFgrhM4QEdRe0Z82F9Qn54= Received: from mail-lf1-f72.google.com (mail-lf1-f72.google.com [209.85.167.72]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-646-hARwh0ElPYa3rkXlBWKcgQ-1; Wed, 27 Jul 2022 22:39:04 -0400 X-MC-Unique: hARwh0ElPYa3rkXlBWKcgQ-1 Received: by mail-lf1-f72.google.com with SMTP id k21-20020ac24f15000000b0048a7a2e246fso226401lfr.7 for ; Wed, 27 Jul 2022 19:39:04 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc:content-transfer-encoding; bh=5ymtTMNSBtFOhhmPgtQl8t8lfFLbeHZYYSYD2cD7gjw=; b=WYIptJ3VDzHL7Lmw3uHE9zN2MGAJfRrarEaSYt8u6WW3ExhP9dDLheEKe0/9XWnKf7 in7SNZrSBOqGQRbJWBCnt/Z8RyfFVy4PsA+YxhUXpN7CKAdiGl/GzZ5ZVowUqRjIQBKH V+olNyC9pnOKkUBpRzFT0FpU4BHscIBg22onCeWclgMD06JiNxWqGGJRBJZGXfakR/qq DuznjcZcD1nzcjSkHmBdwPNf+kNvVRCUcKBPn60qVDW5EdW3Ga7stCBQxHS/CaTjqWQl iKqLNuqBDGRxpWBlYpOCdIjIrwBzPLcPNXfVG3LuU0RVBiConRrdEgKxWks0bC4bU0tq dVGw== X-Gm-Message-State: AJIora9D5SDuudEnsrFkNNMH0u+lBBX3waWv5qzVmwEn87DhZG9DaJER FlXiNvrIFmLsppTifba7r/ex4PL3JiW9UoNuygEY6OImWiq3FoHzErihR5z6nebju5Oya42782r /Y5c6gf17nnQ6NbbjCyfsXnudNWwYXLqxa9gNKJqcmvAQaQxBTw== X-Received: by 2002:a05:651c:2103:b0:25d:6478:2a57 with SMTP id a3-20020a05651c210300b0025d64782a57mr8391223ljq.496.1658975943164; Wed, 27 Jul 2022 19:39:03 -0700 (PDT) X-Google-Smtp-Source: AGRyM1uHdGB5CGdI+a5RxWiQio7u+TOL7GEOspu6vejhdOqf5wuC1xMtb49c5PXiFMMNBwahHTh2HSqnjfW+BjjqQXo= X-Received: by 2002:a05:651c:2103:b0:25d:6478:2a57 with SMTP id a3-20020a05651c210300b0025d64782a57mr8391199ljq.496.1658975942872; Wed, 27 Jul 2022 19:39:02 -0700 (PDT) MIME-Version: 1.0 References: <20220726072225.19884-1-xuanzhuo@linux.alibaba.com> <20220726072225.19884-17-xuanzhuo@linux.alibaba.com> <15aa26f2-f8af-5dbd-f2b2-9270ad873412@redhat.com> <1658907413.1860468-2-xuanzhuo@linux.alibaba.com> In-Reply-To: <1658907413.1860468-2-xuanzhuo@linux.alibaba.com> From: Jason Wang Date: Thu, 28 Jul 2022 10:38:51 +0800 Message-ID: Subject: Re: [PATCH v13 16/42] virtio_ring: split: introduce virtqueue_resize_split() To: Xuan Zhuo Cc: Richard Weinberger , Anton Ivanov , Johannes Berg , "Michael S. Tsirkin" , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Hans de Goede , Mark Gross , Vadim Pasternak , Bjorn Andersson , Mathieu Poirier , Cornelia Huck , Halil Pasic , Eric Farman , Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Christian Borntraeger , Sven Schnelle , Alexei Starovoitov , Daniel Borkmann , Jesper Dangaard Brouer , John Fastabend , Vincent Whitchurch , linux-um@lists.infradead.org, netdev , platform-driver-x86@vger.kernel.org, linux-remoteproc@vger.kernel.org, linux-s390@vger.kernel.org, kvm , "open list:XDP (eXpress Data Path)" , Kangjie Xu , virtualization Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: platform-driver-x86@vger.kernel.org On Wed, Jul 27, 2022 at 3:44 PM Xuan Zhuo wrot= e: > > On Wed, 27 Jul 2022 11:12:19 +0800, Jason Wang wrot= e: > > > > =E5=9C=A8 2022/7/26 15:21, Xuan Zhuo =E5=86=99=E9=81=93: > > > virtio ring split supports resize. > > > > > > Only after the new vring is successfully allocated based on the new n= um, > > > we will release the old vring. In any case, an error is returned, > > > indicating that the vring still points to the old vring. > > > > > > In the case of an error, re-initialize(virtqueue_reinit_split()) the > > > virtqueue to ensure that the vring can be used. > > > > > > Signed-off-by: Xuan Zhuo > > > Acked-by: Jason Wang > > > --- > > > drivers/virtio/virtio_ring.c | 34 +++++++++++++++++++++++++++++++++= + > > > 1 file changed, 34 insertions(+) > > > > > > diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_rin= g.c > > > index b6fda91c8059..58355e1ac7d7 100644 > > > --- a/drivers/virtio/virtio_ring.c > > > +++ b/drivers/virtio/virtio_ring.c > > > @@ -220,6 +220,7 @@ static struct virtqueue *__vring_new_virtqueue(un= signed int index, > > > void (*callback)(struct vi= rtqueue *), > > > const char *name); > > > static struct vring_desc_extra *vring_alloc_desc_extra(unsigned int= num); > > > +static void vring_free(struct virtqueue *_vq); > > > > > > /* > > > * Helpers. > > > @@ -1117,6 +1118,39 @@ static struct virtqueue *vring_create_virtqueu= e_split( > > > return vq; > > > } > > > > > > +static int virtqueue_resize_split(struct virtqueue *_vq, u32 num) > > > +{ > > > + struct vring_virtqueue_split vring_split =3D {}; > > > + struct vring_virtqueue *vq =3D to_vvq(_vq); > > > + struct virtio_device *vdev =3D _vq->vdev; > > > + int err; > > > + > > > + err =3D vring_alloc_queue_split(&vring_split, vdev, num, > > > + vq->split.vring_align, > > > + vq->split.may_reduce_num); > > > + if (err) > > > + goto err; > > > > > > I think we don't need to do anything here? > > Am I missing something? I meant it looks to me most of the virtqueue_reinit() is unnecessary. We probably only need to reinit avail/used idx there. Thanks > > > > > > > > + > > > + err =3D vring_alloc_state_extra_split(&vring_split); > > > + if (err) { > > > + vring_free_split(&vring_split, vdev); > > > + goto err; > > > > > > I suggest to move vring_free_split() into a dedicated error label. > > Will change. > > Thanks. > > > > > > Thanks > > > > > > > + } > > > + > > > + vring_free(&vq->vq); > > > + > > > + virtqueue_vring_init_split(&vring_split, vq); > > > + > > > + virtqueue_init(vq, vring_split.vring.num); > > > + virtqueue_vring_attach_split(vq, &vring_split); > > > + > > > + return 0; > > > + > > > +err: > > > + virtqueue_reinit_split(vq); > > > + return -ENOMEM; > > > +} > > > + > > > > > > /* > > > * Packed ring specific functions - *_packed(). > > >