From: "Michael S. Tsirkin" <mst@redhat.com>
To: Bjorn Helgaas <helgaas@kernel.org>
Cc: Wei Gong <gongwei833x@gmail.com>,
linux-kernel@vger.kernel.org, Bjorn Helgaas <bhelgaas@google.com>,
linux-pci@vger.kernel.org
Subject: Re: [PATCH v2] pci: fix device presence detection for VFs
Date: Sun, 13 Nov 2022 03:46:06 -0500 [thread overview]
Message-ID: <20221113034519-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <20221111234219.GA763705@bhelgaas>
On Fri, Nov 11, 2022 at 05:42:19PM -0600, Bjorn Helgaas wrote:
> On Thu, Nov 10, 2022 at 03:15:55PM -0500, Michael S. Tsirkin wrote:
> > On Thu, Nov 10, 2022 at 01:35:47PM -0600, Bjorn Helgaas wrote:
> > ...
>
> > > Prior to this change pci_device_is_present(VF) returned "false"
> > > (because the VF Vendor ID is 0xffff); after the change it will return
> > > "true" (because it will look at the PF Vendor ID instead).
> > >
> > > Previously virtio_pci_remove() called virtio_break_device(). I guess
> > > that meant the virtio I/O operation will never be completed?
> > >
> > > But if we don't call virtio_break_device(), the virtio I/O operation
> > > *will* be completed?
> >
> > It's completed anyway - nothing special happened at the device
> > level - but driver does not detect it.
> >
> > Calling virtio_break_device will mark all queues as broken, as
> > a result attempts to check whether operation completed
> > will return false.
> >
> > This probably means we need to work on handling surprise removal
> > better in virtio blk - since it looks like actual suprise
> > removal will hang too. But that I think is a separate issue.
>
> Yeah, this situation doesn't seem like it's inherently special for
> virtio or VFs, so it's a little surprising to see
> pci_device_is_present() used there.
>
> Bjorn
Just making sure - pci_device_is_present *is* the suggested way
to distinguish between graceful and surprise removal, isn't it?
--
MST
next prev parent reply other threads:[~2022-11-13 8:47 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-26 6:11 [PATCH v2] pci: fix device presence detection for VFs Michael S. Tsirkin
2022-10-26 13:46 ` Wei Gong
2022-11-08 4:52 ` Wei Gong
2022-11-08 4:58 ` Michael S. Tsirkin
2022-11-08 5:06 ` Bjorn Helgaas
2022-11-10 19:35 ` Bjorn Helgaas
2022-11-10 20:15 ` Michael S. Tsirkin
2022-11-11 23:42 ` Bjorn Helgaas
2022-11-13 8:46 ` Michael S. Tsirkin [this message]
2022-11-15 16:24 ` Bjorn Helgaas
2022-11-16 11:16 ` Lukas Wunner
2022-11-17 5:36 ` Parav Pandit
2022-12-19 5:56 ` Michael S. Tsirkin
2022-12-19 8:22 ` Lukas Wunner
2022-11-11 4:00 ` Wei Gong
2022-11-08 14:53 ` Bjorn Helgaas
2022-11-08 15:02 ` Bjorn Helgaas
2022-11-08 15:19 ` Michael S. Tsirkin
2022-11-08 17:58 ` Bjorn Helgaas
2022-11-08 18:02 ` Michael S. Tsirkin
2022-11-09 4:36 ` Wei Gong
2022-11-09 5:12 ` Bjorn Helgaas
2022-11-09 7:00 ` Wei Gong
2022-11-09 7:10 ` Michael S. Tsirkin
2022-11-09 17:30 ` Bjorn Helgaas
2022-11-09 17:49 ` Michael S. Tsirkin
2022-11-11 23:39 ` Bjorn Helgaas
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