From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A8FC528DC6 for ; Mon, 19 Feb 2024 10:47:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708339648; cv=none; b=nHCwX7DRAq2s/S7oBjiwEFRlVaU5O/LsTOEoatwxCtDnS+BFKzowg7mUxhsZ9fkNFeoptiKhf+vnKjh/HlNg01UnBtls7Zk2O7RT1htoGuSiMwtJK7WuVt1LqY2sD4Qq2ndTgxEM3iCMCLUMVePt6N5gjqfudNLnr+Q7ajIBVGM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708339648; c=relaxed/simple; bh=CbS8EfhDRka7Q6wEyhHmEPKriZqIsMZYy+gfG/xziFs=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: In-Reply-To:Content-Type:Content-Disposition; b=bJQ2CUN6POFLSJGYZhunw04dlTImDndtW4px3DtnhOW1LbB87COe5E4t+xBoJFrKPHGh/LhScTXZCP5oPnbS4tnHiLKK1nBBIszJdoWxIaw6pIsfISV4VgxplUgVPrWb7SnjnitOwRavNAJM81QajzSVCo+jnK+PON9WYx1koaQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=TsbF2j95; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="TsbF2j95" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1708339645; 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=ko3bpSB6LFYSpgZ7lp23nszsYntVgh+j/LkPwXE8CwA=; b=TsbF2j95XHjAGG/7S7+QN/mqiGwhITe9mRUgGZBf9sXKeI2/ow0pRV4xQOQqqwWE3KrDlL RCgMdiZ6IlpxpsYOt9Cy8nuXIL1V0okjo4izn09nW7nEd280P0Y1slma5jVcFKWZwK4GE7 Mz/mzBHW7mL9jkxO5KFnvCC6CYOcPn4= Received: from mail-lj1-f199.google.com (mail-lj1-f199.google.com [209.85.208.199]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-313-jirVbAesOQKqJ_A90G5MTQ-1; Mon, 19 Feb 2024 05:47:19 -0500 X-MC-Unique: jirVbAesOQKqJ_A90G5MTQ-1 Received: by mail-lj1-f199.google.com with SMTP id 38308e7fff4ca-2d0a4fbc9e4so33544561fa.3 for ; Mon, 19 Feb 2024 02:47:18 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1708339637; x=1708944437; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=ko3bpSB6LFYSpgZ7lp23nszsYntVgh+j/LkPwXE8CwA=; b=elPbYlfoOB6WrjS9VbptFh5NK/qKMA+uH6EBus4Vv8/EvOJQJu5MhqpteG6tim/zby O5mS4Akqy7bSoVm+EScxSv+5CtWPwPNTWQqodDMj7844TpZKv5JT78IwEvoEci2gjW5f GFD5mjgHwYj8eGS0Z4tLRaD5yc6ll2eXunjOUjiYbKtTRQGesSTfhAJVXXa8Zg2pMjcr efQQYeQqW36FoYaKDsQqZcY1RGUlwY57z3y8NY7i7CBcF9jj5O1o23OnZbtOQ7oPWtv5 mHTuucbQ81BOEJfbgt0s1vIduLYI0d/3WzJAFWvVVmcYRWCwUl3qOE2LOawCLfG7NyHl ud7A== X-Forwarded-Encrypted: i=1; AJvYcCWRNNJ2GtT1Bu8aMKoM6MdaDoi7/LfF9D+dHDxk9XUa6IMJJAtvr4WOWT7cCkHQ0e1YPraZiK4qA5gZ6fzh3H7FtwJKCuukygLpmgsqmSk= X-Gm-Message-State: AOJu0YwB+g1bfQZLmfAGx3JjzlDkwlXEq1jTqN37OKsviLY3yRongjeP jOMT5NzVshDuxqxO5/QV3jKLIQK8oAYe2nvcnd98yTW7pw6vOpIAeoeW6dgyYuSNyLP0S9Y8B73 BCorAzHTGxZXYMf9Az9mV55Vx2lOUzI0rK1HukDZHmC6O3KJAmYHJgdcmq4X0Uy+c X-Received: by 2002:a2e:8085:0:b0:2d0:c396:f5b2 with SMTP id i5-20020a2e8085000000b002d0c396f5b2mr7365303ljg.27.1708339637610; Mon, 19 Feb 2024 02:47:17 -0800 (PST) X-Google-Smtp-Source: AGHT+IHGhWKUj8jz9hZvXJzX/Lii21jxx3r1v/utV+TrgxtPsn0JzFtwNZxLPfJJLOPwMCNsgx6o/g== X-Received: by 2002:a2e:8085:0:b0:2d0:c396:f5b2 with SMTP id i5-20020a2e8085000000b002d0c396f5b2mr7365295ljg.27.1708339637230; Mon, 19 Feb 2024 02:47:17 -0800 (PST) Received: from redhat.com ([2.52.19.211]) by smtp.gmail.com with ESMTPSA id p6-20020adfe606000000b0033cdbe335bcsm10016533wrm.71.2024.02.19.02.47.15 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 19 Feb 2024 02:47:16 -0800 (PST) Date: Mon, 19 Feb 2024 05:47:13 -0500 From: "Michael S. Tsirkin" To: Parav Pandit Cc: Ming Lei , "jasowang@redhat.com" , "xuanzhuo@linux.alibaba.com" , "pbonzini@redhat.com" , "stefanha@redhat.com" , "axboe@kernel.dk" , "virtualization@lists.linux.dev" , "linux-block@vger.kernel.org" , "stable@vger.kernel.org" , "NBU-Contact-Li Rongqing (EXTERNAL)" , Chaitanya Kulkarni Subject: Re: [PATCH] virtio_blk: Fix device surprise removal Message-ID: <20240219054459-mutt-send-email-mst@kernel.org> References: <20240217180848.241068-1-parav@nvidia.com> <20240219024301-mutt-send-email-mst@kernel.org> Precedence: bulk X-Mailing-List: virtualization@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 In-Reply-To: X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Mon, Feb 19, 2024 at 10:39:36AM +0000, Parav Pandit wrote: > > From: Michael S. Tsirkin > > Sent: Monday, February 19, 2024 1:45 PM > > > > On Mon, Feb 19, 2024 at 03:14:54AM +0000, Parav Pandit wrote: > > > Hi Ming, > > > > > > > From: Ming Lei > > > > Sent: Sunday, February 18, 2024 6:57 PM > > > > > > > > On Sat, Feb 17, 2024 at 08:08:48PM +0200, Parav Pandit wrote: > > > > > When the PCI device is surprise removed, requests won't complete > > > > > from the device. These IOs are never completed and disk deletion > > > > > hangs indefinitely. > > > > > > > > > > Fix it by aborting the IOs which the device will never complete > > > > > when the VQ is broken. > > > > > > > > > > With this fix now fio completes swiftly. > > > > > An alternative of IO timeout has been considered, however when the > > > > > driver knows about unresponsive block device, swiftly clearing > > > > > them enables users and upper layers to react quickly. > > > > > > > > > > Verified with multiple device unplug cycles with pending IOs in > > > > > virtio used ring and some pending with device. > > > > > > > > > > In future instead of VQ broken, a more elegant method can be used. > > > > > At the moment the patch is kept to its minimal changes given its > > > > > urgency to fix broken kernels. > > > > > > > > > > Fixes: 43bb40c5b926 ("virtio_pci: Support surprise removal of > > > > > virtio pci device") > > > > > Cc: stable@vger.kernel.org > > > > > Reported-by: lirongqing@baidu.com > > > > > Closes: > > > > > https://lore.kernel.org/virtualization/c45dd68698cd47238c55fb73ca9 > > > > > b474 > > > > > 1@baidu.com/ > > > > > Co-developed-by: Chaitanya Kulkarni > > > > > Signed-off-by: Chaitanya Kulkarni > > > > > Signed-off-by: Parav Pandit > > > > > --- > > > > > drivers/block/virtio_blk.c | 54 > > > > > ++++++++++++++++++++++++++++++++++++++ > > > > > 1 file changed, 54 insertions(+) > > > > > > > > > > diff --git a/drivers/block/virtio_blk.c > > > > > b/drivers/block/virtio_blk.c index 2bf14a0e2815..59b49899b229 > > > > > 100644 > > > > > --- a/drivers/block/virtio_blk.c > > > > > +++ b/drivers/block/virtio_blk.c > > > > > @@ -1562,10 +1562,64 @@ static int virtblk_probe(struct > > > > > virtio_device > > > > *vdev) > > > > > return err; > > > > > } > > > > > > > > > > +static bool virtblk_cancel_request(struct request *rq, void *data) { > > > > > + struct virtblk_req *vbr = blk_mq_rq_to_pdu(rq); > > > > > + > > > > > + vbr->in_hdr.status = VIRTIO_BLK_S_IOERR; > > > > > + if (blk_mq_request_started(rq) && !blk_mq_request_completed(rq)) > > > > > + blk_mq_complete_request(rq); > > > > > + > > > > > + return true; > > > > > +} > > > > > + > > > > > +static void virtblk_cleanup_reqs(struct virtio_blk *vblk) { > > > > > + struct virtio_blk_vq *blk_vq; > > > > > + struct request_queue *q; > > > > > + struct virtqueue *vq; > > > > > + unsigned long flags; > > > > > + int i; > > > > > + > > > > > + vq = vblk->vqs[0].vq; > > > > > + if (!virtqueue_is_broken(vq)) > > > > > + return; > > > > > + > > > > > > > > What if the surprise happens after the above check? > > > > > > > > > > > In that small timing window, the race still exists. > > > > > > I think, blk_mq_quiesce_queue(q); should move up before cleanup_reqs() > > regardless of surprise case along with other below changes. > > > > > > Additionally, for non-surprise case, better to have a graceful timeout to > > complete already queued requests. > > > In absence of timeout scheme for this regression, shall we only complete the > > requests which the device has already completed (instead of waiting for the > > grace time)? > > > There was past work from Chaitanaya, for the graceful timeout. > > > > > > The sequence for the fix I have in mind is: > > > 1. quiesce the queue > > > 2. complete all requests which has completed, with its status 3. stop > > > the transport (queues) 4. complete remaining pending requests with > > > error status > > > > > > This should work regardless of surprise case. > > > An additional/optional graceful timeout on non-surprise case can be helpful > > for #2. > > > > > > WDYT? > > > > All this is unnecessarily hard for drivers... I am thinking maybe after we set > > broken we should go ahead and invoke all callbacks. > > Yes, #2 is about invoking the callbacks. > > The issue is not with setting the flag broken. As Ming pointed, the issue is : we may miss setting the broken. So if we did get callbacks, we'd be able to test broken flag in the callback. > Without graceful time out it is straight forward code, just rearrangement of APIs in this patch with existing code. > > The question is : it is really if we really care for that grace period when the device or driver is already on its exit path and VQ is not broken. > If we don't wait for the request in progress, is it ok? > If we are talking about physical hardware, it seems quite possible that removal triggers then user gets impatient and yanks the card out. > > interrupt handling core is not making it easy for us - we must disable real > > interrupts if we do, and in the past we failed to do it. > > See e.g. > > > > > > commit eb4cecb453a19b34d5454b49532e09e9cb0c1529 > > Author: Jason Wang > > Date: Wed Mar 23 11:15:24 2022 +0800 > > > > Revert "virtio_pci: harden MSI-X interrupts" > > > > This reverts commit 9e35276a5344f74d4a3600fc4100b3dd251d5c56. > > Issue > > were reported for the drivers that are using affinity managed IRQ > > where manually toggling IRQ status is not expected. And we forget to > > enable the interrupts in the restore path as well. > > > > In the future, we will rework on the interrupt hardening. > > > > Fixes: 9e35276a5344 ("virtio_pci: harden MSI-X interrupts") > > > > > > > > If someone can figure out a way to make toggling interrupt state play nice with > > affinity managed interrupts, that would solve a host of issues I feel. > > > > > > > > > > Thanks, > > > > Ming