Re: [PATCH 16/16] PCI: Unify device inaccessible

From: Lukas Wunner <lukas@wunner.de>
To: Keith Busch <keith.busch@intel.com>
Cc: Linux PCI <linux-pci@vger.kernel.org>,
	Bjorn Helgaas <bhelgaas@google.com>,
	Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Sinan Kaya <okaya@kernel.org>, Thomas Tai <thomas.tai@oracle.com>,
	poza@codeaurora.org
Subject: Re: [PATCH 16/16] PCI: Unify device inaccessible
Date: Sun, 2 Sep 2018 16:39:37 +0200	[thread overview]
Message-ID: <20180902143937.utebcv4cqw6zbb4q@wunner.de> (raw)
In-Reply-To: <20180831212639.10196-17-keith.busch@intel.com>

On Fri, Aug 31, 2018 at 03:26:39PM -0600, Keith Busch wrote:
> --- a/drivers/pci/pci.h
> +++ b/drivers/pci/pci.h
> @@ -294,21 +294,20 @@ struct pci_sriov {
>  static inline int pci_dev_set_disconnected(struct pci_dev *dev, void *unused)
>  {
> -	set_bit(PCI_DEV_DISCONNECTED, &dev->priv_flags);
> +	dev->error_state = pci_channel_io_perm_failure;
>  	return 0;
>  }

Back in 2016 when I floated the idea of using error_state to store
that the device has been removed, you responded:

   "I'd be happy if we can reuse that, but concerned about overloading
    error_state's intended purpose for AER. The conditions under which an
    'is_removed' may be set can also create AER events, and the aer driver
    overrides the error_state."
    https://spinics.net/lists/linux-pci/msg55417.html

Is it guaranteed that AER refrains from writing a different value to
error_state once it has been set to pci_channel_io_perm_failure due
to removal?  If so I'm happy with this patch.

Thanks,

Lukas