[PATCH] NVMe: Unbind driver on failure

[Keith Busch]

ping

On Mon, Mar 28, 2016 at 03:42:39PM -0600, Keith Busch wrote:
> Instead of removing the PCI device from the kernel's topology on
> controller failure, this patch simply requests unbinding the device
> from the driver. This avoids concurrently running pci removal with the
> hot plug event, which has been reported to be problematic when multiple
> surprise events occur near simultaneously.
> 
> The other benefit is that we will have PCI config and memory space
> available to poke around for debugging a failed controller, assuming
> the device was not physically removed.
> 
> The down side occurs if the platform and/or kernel do not support any
> type of surprise hot removal. The device will remain visible through
> sysfs (and therefore lspci), and some manual work is necessary to get
> the logical topology corrected. But if your platform and/or kernel don't
> support surprise removal, you probably shouldn't be doing that anyway.
> 
> Signed-off-by: Keith Busch <keith.busch at intel.com>
> ---
>  drivers/nvme/host/pci.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
> index 660ec84..5acd6e4 100644
> --- a/drivers/nvme/host/pci.c
> +++ b/drivers/nvme/host/pci.c
> @@ -1916,7 +1916,7 @@ static void nvme_remove_dead_ctrl_work(struct work_struct *work)
>  
>  	nvme_kill_queues(&dev->ctrl);
>  	if (pci_get_drvdata(pdev))
> -		pci_stop_and_remove_bus_device_locked(pdev);
> +		device_release_driver(&pdev->dev);
>  	nvme_put_ctrl(&dev->ctrl);
>  }
>  
> -- 
> 2.7.2