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Date:   Fri, 20 Nov 2020 15:57:11 -0600
From:   Bjorn Helgaas <helgaas@kernel.org>
To:     Zhenzhong Duan <zhenzhong.duan@gmail.com>
Cc:     linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org,
        bhelgaas@google.com, hch@infradead.org, alex.williamson@redhat.com,
        cohuck@redhat.com
Subject: Re: [PATCH v3 0/2] avoid inserting duplicate IDs in dynids list
Message-ID: <20201120215711.GA281372@bjorn-Precision-5520>
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In-Reply-To: <20201117054409.3428-1-zhenzhong.duan@gmail.com>
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On Tue, Nov 17, 2020 at 01:44:07PM +0800, Zhenzhong Duan wrote:
> vfio-pci and pci-stub use new_id to bind devices. But one can add same IDs
> multiple times, for example:
> 
> # echo "1af4 1041" > /sys/bus/pci/drivers/vfio-pci/new_id
> # echo "1af4 1041" > /sys/bus/pci/drivers/vfio-pci/new_id
> # echo "1af4 1041" > /sys/bus/pci/drivers/vfio-pci/new_id
> # echo "1af4 1041" > /sys/bus/pci/drivers/vfio-pci/remove_id
> # echo "1af4 1041" > /sys/bus/pci/drivers/vfio-pci/remove_id
> # echo "1af4 1041" > /sys/bus/pci/drivers/vfio-pci/remove_id
> # echo "1af4 1041" > /sys/bus/pci/drivers/vfio-pci/remove_id
> -bash: echo: write error: No such device
> 
> This doesn't cause user-visible broken behavior, but not user friendly.
> he has to remove same IDs same times to ensure it's completely gone.
> 
> Changed to only allow one dynamic entry of the same kind, after fix:
> 
> # echo "1af4 1041" > /sys/bus/pci/drivers/vfio-pci/new_id
> # echo "1af4 1041" > /sys/bus/pci/drivers/vfio-pci/new_id
> -bash: echo: write error: File exists
> # echo "1af4 1041" > /sys/bus/pci/drivers/vfio-pci/remove_id
> # echo "1af4 1041" > /sys/bus/pci/drivers/vfio-pci/remove_id
> -bash: echo: write error: No such device
> 
> 
> v3: add a separate patch to process dependency issue per Bjorn
>     make commit log more clear per Bjorn
> v2: revert the export of pci_match_device() per Christoph
>     combind PATCH1 and PATCH2 into one.
> 
> v2 link:https://lkml.org/lkml/2020/10/25/347
> 
> Zhenzhong Duan (2):
>   PCI: move pci_match_device() ahead of new_id_store()
>   PCI: avoid duplicate IDs in dynamic IDs list
> 
>  drivers/pci/pci-driver.c | 146 +++++++++++++++++++++++------------------------
>  1 file changed, 73 insertions(+), 73 deletions(-)
> 
> -- 
> 1.8.3.1
> 
> 
> Zhenzhong Duan (2):
>   PCI: move pci_match_device() ahead of new_id_store()
>   PCI: avoid duplicate IDs in dynamic IDs list
> 
>  drivers/pci/pci-driver.c | 146 +++++++++++++++++++++++------------------------
>  1 file changed, 73 insertions(+), 73 deletions(-)

I corrected the subject lines:

  PCI: Move pci_match_device() ahead of new_id_store()
  PCI: Avoid duplicate IDs in driver dynamic IDs list

and applied both to pci/enumeration for v5.11, thanks!