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 10EABC433F5 for ; Tue, 12 Apr 2022 06:54:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1350838AbiDLG4w (ORCPT ); Tue, 12 Apr 2022 02:56:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50124 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1351511AbiDLGxx (ORCPT ); Tue, 12 Apr 2022 02:53:53 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 1B6FD37A84 for ; Mon, 11 Apr 2022 23:41:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1649745696; 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=Q0hJ1ezC0n70T2nueon8V1dFA7gdJyx9ipWOKSYhKjA=; b=UA9Y55jBqNBzd7K/zV6sVt9rXoPjFG/fIRaZDAv5KPKhFYLLKCp9l1F9/7/Gk8HAUfZNBx kNQcOC1UnjCdhSUZtyBlJwUUYGAWh4GEhWQO4buLvhiyvgeOGlKk9061im1v7lGFA7Z/NR 38hNtPCdEzbxL0NYRZ0HHtYBG13JuyQ= Received: from mail-pf1-f199.google.com (mail-pf1-f199.google.com [209.85.210.199]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-465-EKoiK29QPney9t09LpYnSA-1; Tue, 12 Apr 2022 02:41:35 -0400 X-MC-Unique: EKoiK29QPney9t09LpYnSA-1 Received: by mail-pf1-f199.google.com with SMTP id x2-20020a628602000000b005057a9b1675so7147322pfd.15 for ; Mon, 11 Apr 2022 23:41:34 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:message-id:date:mime-version:user-agent:subject :content-language:to:cc:references:from:in-reply-to :content-transfer-encoding; bh=Q0hJ1ezC0n70T2nueon8V1dFA7gdJyx9ipWOKSYhKjA=; b=q6Ox4K6pefPnedfXV4FkC0Lvzkjx8priVFy0ogUW1mOjkkjIY+A91fNpvE/7YxxDoh zdP/G8jnmRM3saDd4oZUT0hXNo4963M5tnDETgXh/UkjA6m5FEsTHRse11C+iDV/DqQG 9eNzybRnmIqA0+HS4fehpRimjR5Nk4e648adUSVY8ro33QldOUeXSfOGFlRE8ayVvDNC VdqC/zqm9SPRDkKTn5qUolIOo/Fbbh5c1dU4PaodxK4NPRzSAlkf+s2/y1d1ZXGNPHV3 u36PSk+BWKvvOFKWEwPXSUANdfeqli3sxh0Cx7Yg7tnT2BMQYvrFRR0dVlrjL3hG6d6m ZQ7g== X-Gm-Message-State: AOAM530t8Pm/JS8+DFuNhA2JcJsmJfPL/9N0mxOUr0P42y8F2fezjM2g KJlHIFIhrEikBo+/sB3uPjguqe9+sq7YWalZvMYLW8C9U3uRLsRPF9NbozmtilL1lVPzE4XjQiv iuFdfl27JUsPe/x/2dDMnZw== X-Received: by 2002:aa7:9041:0:b0:4fe:3d6c:1739 with SMTP id n1-20020aa79041000000b004fe3d6c1739mr3123263pfo.13.1649745693969; Mon, 11 Apr 2022 23:41:33 -0700 (PDT) X-Google-Smtp-Source: ABdhPJzcN4j4exOoT+eN9+MrdAypldpi+vnmAZMQ+PJ/c+O0wbKWe6GyXiWgL61SrqAdNRlxVdSHkg== X-Received: by 2002:aa7:9041:0:b0:4fe:3d6c:1739 with SMTP id n1-20020aa79041000000b004fe3d6c1739mr3123226pfo.13.1649745693656; Mon, 11 Apr 2022 23:41:33 -0700 (PDT) Received: from [10.72.14.5] ([209.132.188.80]) by smtp.gmail.com with ESMTPSA id y192-20020a6264c9000000b00505fa595c5asm1265152pfb.129.2022.04.11.23.41.19 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 11 Apr 2022 23:41:33 -0700 (PDT) Message-ID: <92622553-e02d-47bd-06f9-0ce24c22650c@redhat.com> Date: Tue, 12 Apr 2022 14:41:18 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:91.0) Gecko/20100101 Thunderbird/91.7.0 Subject: Re: [PATCH v9 18/32] virtio_ring: introduce virtqueue_resize() Content-Language: en-US To: Xuan Zhuo , virtualization@lists.linux-foundation.org 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, netdev@vger.kernel.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 References: <20220406034346.74409-1-xuanzhuo@linux.alibaba.com> <20220406034346.74409-19-xuanzhuo@linux.alibaba.com> From: Jason Wang In-Reply-To: <20220406034346.74409-19-xuanzhuo@linux.alibaba.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-s390@vger.kernel.org 在 2022/4/6 上午11:43, Xuan Zhuo 写道: > Introduce virtqueue_resize() to implement the resize of vring. > Based on these, the driver can dynamically adjust the size of the vring. > For example: ethtool -G. > > virtqueue_resize() implements resize based on the vq reset function. In > case of failure to allocate a new vring, it will give up resize and use > the original vring. > > During this process, if the re-enable reset vq fails, the vq can no > longer be used. Although the probability of this situation is not high. > > The parameter recycle is used to recycle the buffer that is no longer > used. > > Signed-off-by: Xuan Zhuo > --- > drivers/virtio/virtio_ring.c | 69 ++++++++++++++++++++++++++++++++++++ > include/linux/virtio.h | 3 ++ > 2 files changed, 72 insertions(+) > > diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c > index 06f66b15c86c..6250e19fc5bf 100644 > --- a/drivers/virtio/virtio_ring.c > +++ b/drivers/virtio/virtio_ring.c > @@ -2554,6 +2554,75 @@ struct virtqueue *vring_create_virtqueue( > } > EXPORT_SYMBOL_GPL(vring_create_virtqueue); > > +/** > + * virtqueue_resize - resize the vring of vq > + * @_vq: the struct virtqueue we're talking about. > + * @num: new ring num > + * @recycle: callback for recycle the useless buffer > + * > + * When it is really necessary to create a new vring, it will set the current vq > + * into the reset state. Then call the passed callback to recycle the buffer > + * that is no longer used. Only after the new vring is successfully created, the > + * old vring will be released. > + * > + * Caller must ensure we don't call this with other virtqueue operations > + * at the same time (except where noted). > + * > + * Returns zero or a negative error. Should we document that the virtqueue is kept unchanged (still available) on (specific) failure? > + */ > +int virtqueue_resize(struct virtqueue *_vq, u32 num, > + void (*recycle)(struct virtqueue *vq, void *buf)) > +{ > + struct vring_virtqueue *vq = to_vvq(_vq); > + struct virtio_device *vdev = vq->vq.vdev; > + bool packed; > + void *buf; > + int err; > + > + if (!vq->we_own_ring) > + return -EINVAL; > + > + if (num > vq->vq.num_max) > + return -E2BIG; > + > + if (!num) > + return -EINVAL; > + > + packed = virtio_has_feature(vdev, VIRTIO_F_RING_PACKED) ? true : false; > + > + if ((packed ? vq->packed.vring.num : vq->split.vring.num) == num) > + return 0; > + > + if (!vdev->config->reset_vq) > + return -ENOENT; > + > + if (!vdev->config->enable_reset_vq) > + return -ENOENT; > + > + err = vdev->config->reset_vq(_vq); > + if (err) > + return err; > + > + while ((buf = virtqueue_detach_unused_buf(_vq)) != NULL) > + recycle(_vq, buf); > + > + if (packed) { > + err = virtqueue_resize_packed(_vq, num); > + if (err) > + virtqueue_reinit_packed(vq); Calling reinit here seems a little bit odd, it looks more like a reset of the virtqueue. Consider we may re-use virtqueue reset for more purpose, I wonder if we need a helper like: virtqueue_resize() {     vdev->config->reset_vq(_vq);     if (packed)         virtqueue_reinit_packed(_vq)     else         virtqueue_reinit_split(_vq) } Thanks > + } else { > + err = virtqueue_resize_split(_vq, num); > + if (err) > + virtqueue_reinit_split(vq); > + } > + > + if (vdev->config->enable_reset_vq(_vq)) > + return -EBUSY; > + > + return err; > +} > +EXPORT_SYMBOL_GPL(virtqueue_resize); > + > /* Only available for split ring */ > struct virtqueue *vring_new_virtqueue(unsigned int index, > unsigned int num, > diff --git a/include/linux/virtio.h b/include/linux/virtio.h > index d59adc4be068..c86ff02e0ca0 100644 > --- a/include/linux/virtio.h > +++ b/include/linux/virtio.h > @@ -91,6 +91,9 @@ dma_addr_t virtqueue_get_desc_addr(struct virtqueue *vq); > dma_addr_t virtqueue_get_avail_addr(struct virtqueue *vq); > dma_addr_t virtqueue_get_used_addr(struct virtqueue *vq); > > +int virtqueue_resize(struct virtqueue *vq, u32 num, > + void (*recycle)(struct virtqueue *vq, void *buf)); > + > /** > * virtio_device - representation of a device using virtio > * @index: unique position on the virtio bus