From patchwork Tue Apr 13 05:47:52 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Michael S. Tsirkin" X-Patchwork-Id: 420721 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=-18.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT autolearn=ham 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 0A1D0C433B4 for ; Tue, 13 Apr 2021 05:48:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E6FED613B6 for ; Tue, 13 Apr 2021 05:48:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344646AbhDMFsX (ORCPT ); Tue, 13 Apr 2021 01:48:23 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:26380 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344615AbhDMFsS (ORCPT ); Tue, 13 Apr 2021 01:48:18 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1618292878; 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: in-reply-to:in-reply-to:references:references; bh=6jg8BCGbpMnOAIkNzLWva23V8vKuJlUTOTl6SMonbbA=; b=O6r8sdg+5gYgLX9GRNnhA7wzIWNjgqizxmpx1ehB2sC7c3nRayl+LhSGAFouGQqaH8t59a kJElYbr4LJhsVd/ebDjUrIQBNxJr5mlt0cUrXlcf0YQvLoAqjQtPkaLyMWPIV0yHAeJ+rU eNYx5xltXJsAsbFB2FjKpUeF9Gp3a6I= Received: from mail-wm1-f70.google.com (mail-wm1-f70.google.com [209.85.128.70]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-557-97rGbQ6lPGO3aU-rUxiMgA-1; Tue, 13 Apr 2021 01:47:56 -0400 X-MC-Unique: 97rGbQ6lPGO3aU-rUxiMgA-1 Received: by mail-wm1-f70.google.com with SMTP id u11-20020a05600c00cbb029012a3f52677dso665955wmm.8 for ; Mon, 12 Apr 2021 22:47:56 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=6jg8BCGbpMnOAIkNzLWva23V8vKuJlUTOTl6SMonbbA=; b=qMFi3fKD//ZaT/rIrVuA3wOVCO2PKiYpdMfFv/9ZUqnU1if/cvS9re9KZCukF1FuvM SuSsjlVZAYQnpfqFE+4ctXsAM75E5aBefkwTyR3zaVde8/IuEDpiwygDNrbryV6Nv2eL V3vJImwj2LIMzGdedWydfWTin7DQohuOQUHT6SK8PGuVD/AVvr9rpOHgqwuzgZ4XFPGp 9Y+HbXzpltxnZiavdcBlaFNJZbWipUFXqKIk6QQBmN31YxxYimq14C2U8dG4xl2aUoCY 0DExzptT9h3BdNMzONZrf4PZOwdWJ7I5UpZWEHBEn7q4yGdLgCac76FrYcTLFihbiTk8 q8Og== X-Gm-Message-State: AOAM532u3niJoOwgJdeLddirwkXHCdqghpsiL1Zvg28rzCMi7GFEldSJ vVt2HqzQvQYUR959H5bgJ2hvwdNOPmF+XvylUYji0g8t0C12ALvnwSuop7Froa0ozhhXRJzC4rN pjBuKJ8615VdMKMES X-Received: by 2002:a5d:4e08:: with SMTP id p8mr35572386wrt.4.1618292874760; Mon, 12 Apr 2021 22:47:54 -0700 (PDT) X-Google-Smtp-Source: ABdhPJwlOFgyL/tLR6N8M+xp6zE98QryIgkrAWDLF0SSu1myLxGcVLWj/Riydxj6MeQAxcymfF/BrA== X-Received: by 2002:a5d:4e08:: with SMTP id p8mr35572375wrt.4.1618292874631; Mon, 12 Apr 2021 22:47:54 -0700 (PDT) Received: from redhat.com ([2a10:8006:2281:0:1994:c627:9eac:1825]) by smtp.gmail.com with ESMTPSA id i4sm1264707wmq.12.2021.04.12.22.47.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 12 Apr 2021 22:47:54 -0700 (PDT) Date: Tue, 13 Apr 2021 01:47:52 -0400 From: "Michael S. Tsirkin" To: linux-kernel@vger.kernel.org Cc: Jakub Kicinski , Jason Wang , Wei Wang , David Miller , netdev@vger.kernel.org, Willem de Bruijn , virtualization@lists.linux-foundation.org Subject: [PATCH RFC v2 3/4] virtio_net: move tx vq operation under tx queue lock Message-ID: <20210413054733.36363-4-mst@redhat.com> References: <20210413054733.36363-1-mst@redhat.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20210413054733.36363-1-mst@redhat.com> X-Mailer: git-send-email 2.27.0.106.g8ac3dc51b1 X-Mutt-Fcc: =sent Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org It's unsafe to operate a vq from multiple threads. Unfortunately this is exactly what we do when invoking clean tx poll from rx napi. As a fix move everything that deals with the vq to under tx lock. Signed-off-by: Michael S. Tsirkin --- drivers/net/virtio_net.c | 22 +++++++++++++++++++++- 1 file changed, 21 insertions(+), 1 deletion(-) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 16d5abed582c..460ccdbb840e 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -1505,6 +1505,8 @@ static int virtnet_poll_tx(struct napi_struct *napi, int budget) struct virtnet_info *vi = sq->vq->vdev->priv; unsigned int index = vq2txq(sq->vq); struct netdev_queue *txq; + int opaque; + bool done; if (unlikely(is_xdp_raw_buffer_queue(vi, index))) { /* We don't need to enable cb for XDP */ @@ -1514,10 +1516,28 @@ static int virtnet_poll_tx(struct napi_struct *napi, int budget) txq = netdev_get_tx_queue(vi->dev, index); __netif_tx_lock(txq, raw_smp_processor_id()); + virtqueue_disable_cb(sq->vq); free_old_xmit_skbs(sq, true); + + opaque = virtqueue_enable_cb_prepare(sq->vq); + + done = napi_complete_done(napi, 0); + + if (!done) + virtqueue_disable_cb(sq->vq); + __netif_tx_unlock(txq); - virtqueue_napi_complete(napi, sq->vq, 0); + if (done) { + if (unlikely(virtqueue_poll(sq->vq, opaque))) { + if (napi_schedule_prep(napi)) { + __netif_tx_lock(txq, raw_smp_processor_id()); + virtqueue_disable_cb(sq->vq); + __netif_tx_unlock(txq); + __napi_schedule(napi); + } + } + } if (sq->vq->num_free >= 2 + MAX_SKB_FRAGS) netif_tx_wake_queue(txq);