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 13BB1C43219 for ; Wed, 9 Mar 2022 09:23:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232021AbiCIJYE (ORCPT ); Wed, 9 Mar 2022 04:24:04 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37504 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231297AbiCIJYD (ORCPT ); Wed, 9 Mar 2022 04:24:03 -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 CF0D66C1C2; Wed, 9 Mar 2022 01:23:03 -0800 (PST) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R111e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04426;MF=xuanzhuo@linux.alibaba.com;NM=1;PH=DS;RN=33;SR=0;TI=SMTPD_---0V6iwYED_1646817777; Received: from localhost(mailfrom:xuanzhuo@linux.alibaba.com fp:SMTPD_---0V6iwYED_1646817777) by smtp.aliyun-inc.com(127.0.0.1); Wed, 09 Mar 2022 17:22:58 +0800 Message-ID: <1646817741.6086373-5-xuanzhuo@linux.alibaba.com> Subject: Re: [PATCH v7 08/26] virtio_ring: extract the logic of freeing vring Date: Wed, 9 Mar 2022 17:22:21 +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> <20220308123518.33800-9-xuanzhuo@linux.alibaba.com> In-Reply-To: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Wed, 9 Mar 2022 15:51:13 +0800, Jason Wang wrote: > > =E5=9C=A8 2022/3/8 =E4=B8=8B=E5=8D=888:35, Xuan Zhuo =E5=86=99=E9=81=93: > > Introduce vring_free() to free the vring of vq. > > > > Prevent double free by setting vq->reset. > > > > Signed-off-by: Xuan Zhuo > > --- > > drivers/virtio/virtio_ring.c | 25 ++++++++++++++++++++----- > > include/linux/virtio.h | 8 ++++++++ > > 2 files changed, 28 insertions(+), 5 deletions(-) > > > > diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c > > index b5a9bf4f45b3..e0422c04c903 100644 > > --- a/drivers/virtio/virtio_ring.c > > +++ b/drivers/virtio/virtio_ring.c > > @@ -2442,14 +2442,10 @@ struct virtqueue *vring_new_virtqueue(unsigned = int index, > > } > > EXPORT_SYMBOL_GPL(vring_new_virtqueue); > > > > -void vring_del_virtqueue(struct virtqueue *_vq) > > +static void __vring_free(struct virtqueue *_vq) > > { > > struct vring_virtqueue *vq =3D to_vvq(_vq); > > > > - spin_lock(&vq->vq.vdev->vqs_list_lock); > > - list_del(&_vq->list); > > - spin_unlock(&vq->vq.vdev->vqs_list_lock); > > - > > if (vq->we_own_ring) { > > if (vq->packed_ring) { > > vring_free_queue(vq->vq.vdev, > > @@ -2480,6 +2476,25 @@ void vring_del_virtqueue(struct virtqueue *_vq) > > kfree(vq->split.desc_state); > > kfree(vq->split.desc_extra); > > } > > +} > > + > > +static void vring_free(struct virtqueue *vq) > > +{ > > + __vring_free(vq); > > + vq->reset =3D VIRTIO_VQ_RESET_STEP_VRING_RELEASE; > > +} > > + > > +void vring_del_virtqueue(struct virtqueue *_vq) > > +{ > > + struct vring_virtqueue *vq =3D to_vvq(_vq); > > + > > + spin_lock(&vq->vq.vdev->vqs_list_lock); > > + list_del(&_vq->list); > > + spin_unlock(&vq->vq.vdev->vqs_list_lock); > > + > > + if (_vq->reset !=3D VIRTIO_VQ_RESET_STEP_VRING_RELEASE) > > + __vring_free(_vq); > > + > > kfree(vq); > > } > > EXPORT_SYMBOL_GPL(vring_del_virtqueue); > > diff --git a/include/linux/virtio.h b/include/linux/virtio.h > > index d59adc4be068..e3714e6db330 100644 > > --- a/include/linux/virtio.h > > +++ b/include/linux/virtio.h > > @@ -10,6 +10,13 @@ > > #include > > #include > > > > +enum virtio_vq_reset_step { > > + VIRTIO_VQ_RESET_STEP_NONE, > > + VIRTIO_VQ_RESET_STEP_DEVICE, > > + VIRTIO_VQ_RESET_STEP_VRING_RELEASE, > > + VIRTIO_VQ_RESET_STEP_VRING_ATTACH, > > +}; > > > This part looks not related to the subject. > > And it needs detail documentation on this. > > But I wonder how useful it is, anyway we can check the reset status via > transport specific way and in the future we may want to do more than > just resizing (e.g PASID). I will try and remove it from here. Thanks. > > Thanks > > > > + > > /** > > * virtqueue - a queue to register buffers for sending or receiving. > > * @list: the chain of virtqueues for this device > > @@ -33,6 +40,7 @@ struct virtqueue { > > unsigned int num_free; > > unsigned int num_max; > > void *priv; > > + enum virtio_vq_reset_step reset; > > }; > > > > int virtqueue_add_outbuf(struct virtqueue *vq, >