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 17561C433F5 for ; Mon, 17 Jan 2022 08:32:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238215AbiAQIcE (ORCPT ); Mon, 17 Jan 2022 03:32:04 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]:37681 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238214AbiAQIcC (ORCPT ); Mon, 17 Jan 2022 03:32:02 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1642408321; 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=vaBNs95WDlXx8iGl0AyfpROH/j47Hay2zVSLmFsrGtg=; b=Mq8yNpeEq2DZTB2XDE10++mLPAMFwqc9tz8XhoL9Xse00bZfhLMxOCIeGKniUI8XyLMEvJ zTpr0HNxa0bOL8C5ATCwzUuUn0b4MroZnc4RaAG+jxRBjnwVjepScfVuTfGij2ZhTzHZjM NQ89IhJtqnDW05DdGGg5OirnwssqP60= Received: from mail-ed1-f70.google.com (mail-ed1-f70.google.com [209.85.208.70]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-495-hMf16PxePYCDn8kyu880Dw-1; Mon, 17 Jan 2022 03:31:59 -0500 X-MC-Unique: hMf16PxePYCDn8kyu880Dw-1 Received: by mail-ed1-f70.google.com with SMTP id cf15-20020a0564020b8f00b0040284b671c6so2407509edb.22 for ; Mon, 17 Jan 2022 00:31:59 -0800 (PST) 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 :content-language:to:cc:references:from:organization:subject :in-reply-to:content-transfer-encoding; bh=vaBNs95WDlXx8iGl0AyfpROH/j47Hay2zVSLmFsrGtg=; b=ffjWhgrcaKqhEMxv0ZnXASmmjpIGIMHtoZQzlg3GhD2KUMtma2/lwqrPrv8HVi2fK0 I4qJ2tglgcY2MjYDANKgGA0jI7WoVMPkVsO4ZNvoEpfCmRghpHI+Pc9xnC20jZg737qh QdIHpbv54lvRrU8GrlC9OYly/Go2Bh47RwnVfI7TeN7xejjnGHKgIFk5e7g2Ezx7xs0l jVPbb0ixv3Oag+T11K8E+FKb5yLRXSjOQKyiJkKjIvpQKA1LRoEPHkQw48PG/mop+uzn rDI1v/yr9PV3ZTDA4vsUlc/ujBpQgULdT14MUiM6CfBpkvQCQSLSsOyR32Ou4DO5mmUM yHwQ== X-Gm-Message-State: AOAM530fY13fI+MlXLYpz3uxb2Q7QfMZglidrnEgpbWu75Su15e4LuDZ ZwTMo8i6SPI12KcegBMQ7LKh2ag9HVin/oYsHkq2idt2a6y0QblyzPOLCuN5v+so1cgX5Som/e4 R/K/BuehSMAafn9CUilJf9Nr0 X-Received: by 2002:aa7:c609:: with SMTP id h9mr20143855edq.248.1642408318293; Mon, 17 Jan 2022 00:31:58 -0800 (PST) X-Google-Smtp-Source: ABdhPJzgZa/KW4xGU199wi9i9/KP8wY0G54upJDfddwLxn3V0PbEj2XKQGZhKuv6oRoWoO1Yxc7NKg== X-Received: by 2002:aa7:c609:: with SMTP id h9mr20143839edq.248.1642408318111; Mon, 17 Jan 2022 00:31:58 -0800 (PST) Received: from ?IPV6:2003:cb:c705:dd00:68a1:1bd:6733:bde9? (p200300cbc705dd0068a101bd6733bde9.dip0.t-ipconnect.de. [2003:cb:c705:dd00:68a1:1bd:6733:bde9]) by smtp.gmail.com with ESMTPSA id b19sm2463073edr.40.2022.01.17.00.31.57 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 17 Jan 2022 00:31:57 -0800 (PST) Message-ID: <7ec8218e-9d76-a9b7-ccd0-b7c8ce257fe2@redhat.com> Date: Mon, 17 Jan 2022 09:31:56 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.4.0 Content-Language: en-US To: "Michael S. Tsirkin" , Jason Wang Cc: linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org References: <20220114214324.239444-1-mst@redhat.com> <1f703ebf-0f78-e530-0fe1-163613397cad@redhat.com> <20220117025341-mutt-send-email-mst@kernel.org> From: David Hildenbrand Organization: Red Hat Subject: Re: [PATCH] virtio_mem: break device on remove In-Reply-To: <20220117025341-mutt-send-email-mst@kernel.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 17.01.22 08:55, Michael S. Tsirkin wrote: > On Mon, Jan 17, 2022 at 02:40:11PM +0800, Jason Wang wrote: >> >> 在 2022/1/15 上午5:43, Michael S. Tsirkin 写道: >>> A common pattern for device reset is currently: >>> vdev->config->reset(vdev); >>> .. cleanup .. >>> >>> reset prevents new interrupts from arriving and waits for interrupt >>> handlers to finish. >>> >>> However if - as is common - the handler queues a work request which is >>> flushed during the cleanup stage, we have code adding buffers / trying >>> to get buffers while device is reset. Not good. >>> >>> This was reproduced by running >>> modprobe virtio_console >>> modprobe -r virtio_console >>> in a loop, and this reasoning seems to apply to virtio mem though >>> I could not reproduce it there. >>> >>> Fix this up by calling virtio_break_device + flush before reset. >>> >>> Signed-off-by: Michael S. Tsirkin >>> --- >>> drivers/virtio/virtio_mem.c | 2 ++ >>> 1 file changed, 2 insertions(+) >>> >>> diff --git a/drivers/virtio/virtio_mem.c b/drivers/virtio/virtio_mem.c >>> index 38becd8d578c..33b8a118a3ae 100644 >>> --- a/drivers/virtio/virtio_mem.c >>> +++ b/drivers/virtio/virtio_mem.c >>> @@ -2888,6 +2888,8 @@ static void virtio_mem_remove(struct virtio_device *vdev) >>> virtio_mem_deinit_hotplug(vm); >>> /* reset the device and cleanup the queues */ >>> + virtio_break_device(vdev); >>> + flush_work(&vm->wq); >> >> >> We set vm->removing to true and call cancel_work_sync() in >> virtio_mem_deinit_hotplug(). Isn't is sufficient? >> >> Thanks > > > Hmm I think you are right. David, I will drop this for now. > Up to you to consider whether some central capability will be > helpful as a replacement for the virtio-mem specific "removing" flag. It's all a bit tricky because we also have to handle pending timers and pending memory onlining/offlining operations in a controlled way. Maybe we could convert to virtio_break_device() and use the &dev->vqs_list_lock as a replacement for the removal_lock. However, I'm not 100% sure if it's nice to use that lock from drivers/virtio/virtio_mem.c directly. -- Thanks, David / dhildenb 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 smtp1.osuosl.org (smtp1.osuosl.org [140.211.166.138]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id A57F4C433FE for ; Mon, 17 Jan 2022 08:32:06 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp1.osuosl.org (Postfix) with ESMTP id 341B380B5D; Mon, 17 Jan 2022 08:32:06 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp1.osuosl.org ([127.0.0.1]) by localhost (smtp1.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id fSKHL2XuD69H; Mon, 17 Jan 2022 08:32:05 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by smtp1.osuosl.org (Postfix) with ESMTPS id BBC2181376; Mon, 17 Jan 2022 08:32:04 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 96EAFC0031; Mon, 17 Jan 2022 08:32:04 +0000 (UTC) Received: from smtp3.osuosl.org (smtp3.osuosl.org [IPv6:2605:bc80:3010::136]) by lists.linuxfoundation.org (Postfix) with ESMTP id 6373FC002F for ; Mon, 17 Jan 2022 08:32:03 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp3.osuosl.org (Postfix) with ESMTP id 4A4B760615 for ; Mon, 17 Jan 2022 08:32:03 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Authentication-Results: smtp3.osuosl.org (amavisd-new); dkim=pass (1024-bit key) header.d=redhat.com Received: from smtp3.osuosl.org ([127.0.0.1]) by localhost (smtp3.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 7nIpbUY8Yag8 for ; Mon, 17 Jan 2022 08:32:02 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.8.0 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by smtp3.osuosl.org (Postfix) with ESMTPS id 972B4605E8 for ; Mon, 17 Jan 2022 08:32:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1642408321; 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=vaBNs95WDlXx8iGl0AyfpROH/j47Hay2zVSLmFsrGtg=; b=Mq8yNpeEq2DZTB2XDE10++mLPAMFwqc9tz8XhoL9Xse00bZfhLMxOCIeGKniUI8XyLMEvJ zTpr0HNxa0bOL8C5ATCwzUuUn0b4MroZnc4RaAG+jxRBjnwVjepScfVuTfGij2ZhTzHZjM NQ89IhJtqnDW05DdGGg5OirnwssqP60= Received: from mail-ed1-f70.google.com (mail-ed1-f70.google.com [209.85.208.70]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-520-qtRrliWAOny3Jv_gSTINdw-1; Mon, 17 Jan 2022 03:31:59 -0500 X-MC-Unique: qtRrliWAOny3Jv_gSTINdw-1 Received: by mail-ed1-f70.google.com with SMTP id j10-20020a05640211ca00b003ff0e234fdfso13597107edw.0 for ; Mon, 17 Jan 2022 00:31:59 -0800 (PST) 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 :content-language:to:cc:references:from:organization:subject :in-reply-to:content-transfer-encoding; bh=vaBNs95WDlXx8iGl0AyfpROH/j47Hay2zVSLmFsrGtg=; b=pfZ1kZteDcvtgKbAbMOLt9RK3ycgcdP033Kng6rUauWaUVlnUuWy14v1l1dne/lvVT Kwdiu14VziJ6CAFZjpJtmDXTnD52VDkc5VoUxXE6szTuywVa6Km16nvRodV/i+VIBsyn hoaJbJYxygoUjSA7CuirvIhMk9rSqGHuYHwls/CYR/LBYsQmz6vNTSP7D0/EOR5fqFBO m3MhDwAs3OYhxXTPGpVd4p1dFhGYsZDhdg62N5zeBbjga/pQSAQdNNjZ/BQg2/n+T2IU 2eOa5D69ZCa/pCuWML81vXTHOMgdVbzzqNldIBlsd0dySprLi5K5lOenGYRKV2rYh3Yl w5dg== X-Gm-Message-State: AOAM531NogBc17spDYCZ76t6xiKxBDEKxcgWE0dObW5H1fkZgVQR/9Ez XRod1JRjF+RQyDFTPYKyB2w2ZjthT19vW+OwOmrrIShZ42u/MXUa+HFv70XUdtf+hj1rvARzIWn paAD7q8paP7ifcVXhxqYElM3JF0/ROp21+hwMfJ/ZPQ== X-Received: by 2002:aa7:c609:: with SMTP id h9mr20143854edq.248.1642408318293; Mon, 17 Jan 2022 00:31:58 -0800 (PST) X-Google-Smtp-Source: ABdhPJzgZa/KW4xGU199wi9i9/KP8wY0G54upJDfddwLxn3V0PbEj2XKQGZhKuv6oRoWoO1Yxc7NKg== X-Received: by 2002:aa7:c609:: with SMTP id h9mr20143839edq.248.1642408318111; Mon, 17 Jan 2022 00:31:58 -0800 (PST) Received: from ?IPV6:2003:cb:c705:dd00:68a1:1bd:6733:bde9? 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Tsirkin" , Jason Wang References: <20220114214324.239444-1-mst@redhat.com> <1f703ebf-0f78-e530-0fe1-163613397cad@redhat.com> <20220117025341-mutt-send-email-mst@kernel.org> From: David Hildenbrand Organization: Red Hat Subject: Re: [PATCH] virtio_mem: break device on remove In-Reply-To: <20220117025341-mutt-send-email-mst@kernel.org> Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=david@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US Cc: linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org X-BeenThere: virtualization@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Linux virtualization List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Errors-To: virtualization-bounces@lists.linux-foundation.org Sender: "Virtualization" T24gMTcuMDEuMjIgMDg6NTUsIE1pY2hhZWwgUy4gVHNpcmtpbiB3cm90ZToKPiBPbiBNb24sIEph biAxNywgMjAyMiBhdCAwMjo0MDoxMVBNICswODAwLCBKYXNvbiBXYW5nIHdyb3RlOgo+Pgo+PiDl nKggMjAyMi8xLzE1IOS4iuWNiDU6NDMsIE1pY2hhZWwgUy4gVHNpcmtpbiDlhpnpgZM6Cj4+PiBB IGNvbW1vbiBwYXR0ZXJuIGZvciBkZXZpY2UgcmVzZXQgaXMgY3VycmVudGx5Ogo+Pj4gdmRldi0+ Y29uZmlnLT5yZXNldCh2ZGV2KTsKPj4+IC4uIGNsZWFudXAgLi4KPj4+Cj4+PiByZXNldCBwcmV2 ZW50cyBuZXcgaW50ZXJydXB0cyBmcm9tIGFycml2aW5nIGFuZCB3YWl0cyBmb3IgaW50ZXJydXB0 Cj4+PiBoYW5kbGVycyB0byBmaW5pc2guCj4+Pgo+Pj4gSG93ZXZlciBpZiAtIGFzIGlzIGNvbW1v biAtIHRoZSBoYW5kbGVyIHF1ZXVlcyBhIHdvcmsgcmVxdWVzdCB3aGljaCBpcwo+Pj4gZmx1c2hl ZCBkdXJpbmcgdGhlIGNsZWFudXAgc3RhZ2UsIHdlIGhhdmUgY29kZSBhZGRpbmcgYnVmZmVycyAv IHRyeWluZwo+Pj4gdG8gZ2V0IGJ1ZmZlcnMgd2hpbGUgZGV2aWNlIGlzIHJlc2V0LiBOb3QgZ29v ZC4KPj4+Cj4+PiBUaGlzIHdhcyByZXByb2R1Y2VkIGJ5IHJ1bm5pbmcKPj4+IAltb2Rwcm9iZSB2 aXJ0aW9fY29uc29sZQo+Pj4gCW1vZHByb2JlIC1yIHZpcnRpb19jb25zb2xlCj4+PiBpbiBhIGxv b3AsIGFuZCB0aGlzIHJlYXNvbmluZyBzZWVtcyB0byBhcHBseSB0byB2aXJ0aW8gbWVtIHRob3Vn aAo+Pj4gSSBjb3VsZCBub3QgcmVwcm9kdWNlIGl0IHRoZXJlLgo+Pj4KPj4+IEZpeCB0aGlzIHVw IGJ5IGNhbGxpbmcgdmlydGlvX2JyZWFrX2RldmljZSArIGZsdXNoIGJlZm9yZSByZXNldC4KPj4+ Cj4+PiBTaWduZWQtb2ZmLWJ5OiBNaWNoYWVsIFMuIFRzaXJraW4gPG1zdEByZWRoYXQuY29tPgo+ Pj4gLS0tCj4+PiAgIGRyaXZlcnMvdmlydGlvL3ZpcnRpb19tZW0uYyB8IDIgKysKPj4+ICAgMSBm aWxlIGNoYW5nZWQsIDIgaW5zZXJ0aW9ucygrKQo+Pj4KPj4+IGRpZmYgLS1naXQgYS9kcml2ZXJz L3ZpcnRpby92aXJ0aW9fbWVtLmMgYi9kcml2ZXJzL3ZpcnRpby92aXJ0aW9fbWVtLmMKPj4+IGlu ZGV4IDM4YmVjZDhkNTc4Yy4uMzNiOGExMThhM2FlIDEwMDY0NAo+Pj4gLS0tIGEvZHJpdmVycy92 aXJ0aW8vdmlydGlvX21lbS5jCj4+PiArKysgYi9kcml2ZXJzL3ZpcnRpby92aXJ0aW9fbWVtLmMK Pj4+IEBAIC0yODg4LDYgKzI4ODgsOCBAQCBzdGF0aWMgdm9pZCB2aXJ0aW9fbWVtX3JlbW92ZShz dHJ1Y3QgdmlydGlvX2RldmljZSAqdmRldikKPj4+ICAgCQl2aXJ0aW9fbWVtX2RlaW5pdF9ob3Rw bHVnKHZtKTsKPj4+ICAgCS8qIHJlc2V0IHRoZSBkZXZpY2UgYW5kIGNsZWFudXAgdGhlIHF1ZXVl cyAqLwo+Pj4gKwl2aXJ0aW9fYnJlYWtfZGV2aWNlKHZkZXYpOwo+Pj4gKwlmbHVzaF93b3JrKCZ2 bS0+d3EpOwo+Pgo+Pgo+PiBXZSBzZXQgdm0tPnJlbW92aW5nIHRvIHRydWUgYW5kIGNhbGwgY2Fu Y2VsX3dvcmtfc3luYygpIGluCj4+IHZpcnRpb19tZW1fZGVpbml0X2hvdHBsdWcoKS4gSXNuJ3Qg aXMgc3VmZmljaWVudD8KPj4KPj4gVGhhbmtzCj4gCj4gCj4gSG1tIEkgdGhpbmsgeW91IGFyZSBy aWdodC4gRGF2aWQsIEkgd2lsbCBkcm9wIHRoaXMgZm9yIG5vdy4KPiBVcCB0byB5b3UgdG8gY29u c2lkZXIgd2hldGhlciBzb21lIGNlbnRyYWwgY2FwYWJpbGl0eSB3aWxsIGJlCj4gaGVscGZ1bCBh cyBhIHJlcGxhY2VtZW50IGZvciB0aGUgdmlydGlvLW1lbSBzcGVjaWZpYyAicmVtb3ZpbmciIGZs YWcuCgpJdCdzIGFsbCBhIGJpdCB0cmlja3kgYmVjYXVzZSB3ZSBhbHNvIGhhdmUgdG8gaGFuZGxl IHBlbmRpbmcgdGltZXJzIGFuZApwZW5kaW5nIG1lbW9yeSBvbmxpbmluZy9vZmZsaW5pbmcgb3Bl cmF0aW9ucyBpbiBhIGNvbnRyb2xsZWQgd2F5LiBNYXliZQp3ZSBjb3VsZCBjb252ZXJ0IHRvIHZp cnRpb19icmVha19kZXZpY2UoKSBhbmQgdXNlIHRoZQomZGV2LT52cXNfbGlzdF9sb2NrIGFzIGEg cmVwbGFjZW1lbnQgZm9yIHRoZSByZW1vdmFsX2xvY2suIEhvd2V2ZXIsIEknbQpub3QgMTAwJSBz dXJlIGlmIGl0J3MgbmljZSB0byB1c2UgdGhhdCBsb2NrIGZyb20KZHJpdmVycy92aXJ0aW8vdmly dGlvX21lbS5jIGRpcmVjdGx5LgotLSAKVGhhbmtzLAoKRGF2aWQgLyBkaGlsZGVuYgoKX19fX19f X19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX18KVmlydHVhbGl6YXRpb24g bWFpbGluZyBsaXN0ClZpcnR1YWxpemF0aW9uQGxpc3RzLmxpbnV4LWZvdW5kYXRpb24ub3JnCmh0 dHBzOi8vbGlzdHMubGludXhmb3VuZGF0aW9uLm9yZy9tYWlsbWFuL2xpc3RpbmZvL3ZpcnR1YWxp emF0aW9u