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 D14AFC43219 for ; Wed, 9 Mar 2022 09:20:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231986AbiCIJVv (ORCPT ); Wed, 9 Mar 2022 04:21:51 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34000 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229744AbiCIJVu (ORCPT ); Wed, 9 Mar 2022 04:21:50 -0500 Received: from out30-42.freemail.mail.aliyun.com (out30-42.freemail.mail.aliyun.com [115.124.30.42]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CFE4E3465F; Wed, 9 Mar 2022 01:20:50 -0800 (PST) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R231e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04394;MF=xuanzhuo@linux.alibaba.com;NM=1;PH=DS;RN=33;SR=0;TI=SMTPD_---0V6j5tde_1646817644; Received: from localhost(mailfrom:xuanzhuo@linux.alibaba.com fp:SMTPD_---0V6j5tde_1646817644) by smtp.aliyun-inc.com(127.0.0.1); Wed, 09 Mar 2022 17:20:45 +0800 Message-ID: <1646817603.8985817-3-xuanzhuo@linux.alibaba.com> Subject: Re: [PATCH v7 04/26] virtio_ring: split: extract the logic of creating vring Date: Wed, 9 Mar 2022 17:20:03 +0800 From: Xuan Zhuo To: Jason Wang Cc: Jeff Dike , Richard Weinberger , Anton Ivanov , "Michael S. Tsirkin" , "David S. Miller" , Jakub Kicinski , Hans de Goede , Mark Gross , Vadim Pasternak , Bjorn Andersson , Mathieu Poirier , Cornelia Huck , Halil Pasic , Heiko Carstens , Vasily Gorbik , Christian Borntraeger , Alexander Gordeev , Sven Schnelle , Alexei Starovoitov , Daniel Borkmann , Jesper Dangaard Brouer , John Fastabend , Johannes Berg , Vincent Whitchurch , linux-um@lists.infradead.org, platform-driver-x86@vger.kernel.org, linux-remoteproc@vger.kernel.org, linux-s390@vger.kernel.org, kvm@vger.kernel.org, bpf@vger.kernel.org, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org References: <20220308123518.33800-1-xuanzhuo@linux.alibaba.com> <20220308123518.33800-5-xuanzhuo@linux.alibaba.com> <4b32d0b4-b794-cc1c-25f7-50b5ea6ac25e@redhat.com> In-Reply-To: <4b32d0b4-b794-cc1c-25f7-50b5ea6ac25e@redhat.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Agree for all. Thanks. On Wed, 9 Mar 2022 14:46:01 +0800, Jason Wang wrote: > > =E5=9C=A8 2022/3/8 =E4=B8=8B=E5=8D=888:34, Xuan Zhuo =E5=86=99=E9=81=93: > > Separate the logic of split to create vring queue. > > > > For the convenience of passing parameters, add a structure > > vring_split. > > > > This feature is required for subsequent virtuqueue reset vring. > > > > Signed-off-by: Xuan Zhuo > > --- > > drivers/virtio/virtio_ring.c | 74 +++++++++++++++++++++++++----------- > > 1 file changed, 51 insertions(+), 23 deletions(-) > > > > diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c > > index b87130c8f312..d32793615451 100644 > > --- a/drivers/virtio/virtio_ring.c > > +++ b/drivers/virtio/virtio_ring.c > > @@ -85,6 +85,13 @@ struct vring_desc_extra { > > u16 next; /* The next desc state in a list. */ > > }; > > > > +struct vring_split { > > + void *queue; > > + dma_addr_t dma_addr; > > + size_t queue_size_in_bytes; > > + struct vring vring; > > +}; > > > So this structure will be only used in vring_create_vring_split() which > seems not that useful. > > More see below. > > > > + > > struct vring_virtqueue { > > struct virtqueue vq; > > > > @@ -915,28 +922,21 @@ static void *virtqueue_detach_unused_buf_split(st= ruct virtqueue *_vq) > > return NULL; > > } > > > > -static struct virtqueue *vring_create_virtqueue_split( > > - unsigned int index, > > - unsigned int num, > > - unsigned int vring_align, > > - struct virtio_device *vdev, > > - bool weak_barriers, > > - bool may_reduce_num, > > - bool context, > > - bool (*notify)(struct virtqueue *), > > - void (*callback)(struct virtqueue *), > > - const char *name) > > +static int vring_create_vring_split(struct vring_split *vring, > > + struct virtio_device *vdev, > > + unsigned int vring_align, > > + bool weak_barriers, > > + bool may_reduce_num, > > + u32 num) > > > I'd rename this as vring_alloc_queue_split() and let it simply return > the address of queue like vring_alloc_queue(). > > And let it simple accept dma_addr_t *dma_adder instead of vring_split. > > > > { > > - struct virtqueue *vq; > > void *queue =3D NULL; > > dma_addr_t dma_addr; > > size_t queue_size_in_bytes; > > - struct vring vring; > > > > /* We assume num is a power of 2. */ > > if (num & (num - 1)) { > > dev_warn(&vdev->dev, "Bad virtqueue length %u\n", num); > > - return NULL; > > + return -EINVAL; > > } > > > > /* TODO: allocate each queue chunk individually */ > > @@ -947,11 +947,11 @@ static struct virtqueue *vring_create_virtqueue_s= plit( > > if (queue) > > break; > > if (!may_reduce_num) > > - return NULL; > > + return -ENOMEM; > > } > > > > if (!num) > > - return NULL; > > + return -ENOMEM; > > > > if (!queue) { > > /* Try to get a single page. You are my only hope! */ > > @@ -959,21 +959,49 @@ static struct virtqueue *vring_create_virtqueue_s= plit( > > &dma_addr, GFP_KERNEL|__GFP_ZERO); > > } > > if (!queue) > > - return NULL; > > + return -ENOMEM; > > > > queue_size_in_bytes =3D vring_size(num, vring_align); > > - vring_init(&vring, num, queue, vring_align); > > + vring_init(&vring->vring, num, queue, vring_align); > > > It's better to move this to its caller (vring_create_virtqueue_split), > so we have rather simple logic below: > > > > > + > > + vring->dma_addr =3D dma_addr; > > + vring->queue =3D queue; > > + vring->queue_size_in_bytes =3D queue_size_in_bytes; > > + > > + return 0; > > +} > > + > > +static struct virtqueue *vring_create_virtqueue_split( > > + unsigned int index, > > + unsigned int num, > > + unsigned int vring_align, > > + struct virtio_device *vdev, > > + bool weak_barriers, > > + bool may_reduce_num, > > + bool context, > > + bool (*notify)(struct virtqueue *), > > + void (*callback)(struct virtqueue *), > > + const char *name) > > +{ > > + struct vring_split vring; > > + struct virtqueue *vq; > > + int err; > > + > > + err =3D vring_create_vring_split(&vring, vdev, vring_align, weak_barr= iers, > > + may_reduce_num, num); > > + if (err) > > + return NULL; > > > queue =3D vring_alloc_queue_split(vdev, &dma_addr, ...); > > if (!queue) > > =C2=A0=C2=A0=C2=A0 return -ENOMEM; > > vring_init(); > > ... > > Thanks > > > > > > - vq =3D __vring_new_virtqueue(index, vring, vdev, weak_barriers, conte= xt, > > + vq =3D __vring_new_virtqueue(index, vring.vring, vdev, weak_barriers,= context, > > notify, callback, name); > > if (!vq) { > > - vring_free_queue(vdev, queue_size_in_bytes, queue, > > - dma_addr); > > + vring_free_queue(vdev, vring.queue_size_in_bytes, vring.queue, > > + vring.dma_addr); > > return NULL; > > } > > > > - to_vvq(vq)->split.queue_dma_addr =3D dma_addr; > > - to_vvq(vq)->split.queue_size_in_bytes =3D queue_size_in_bytes; > > + to_vvq(vq)->split.queue_dma_addr =3D vring.dma_addr; > > + to_vvq(vq)->split.queue_size_in_bytes =3D vring.queue_size_in_bytes; > > to_vvq(vq)->we_own_ring =3D true; > > > > return vq; >