Re: [PATCH v7 3/3] PCI: xilinx-xdma: Add Xilinx XDMA Root Port driver

[Bjorn Helgaas]

On Wed, Aug 30, 2023 at 02:37:07PM +0530, Thippeswamy Havalige wrote:
> Add support for Xilinx XDMA Soft IP core as Root Port.
> 
> The Zynq UltraScale+ MPSoCs devices support XDMA soft IP module in
> programmable logic.
> 
> The integrated XDMA soft IP block has integrated bridge function that
> can act as PCIe Root Port.

> +	if (!pci_is_root_bus(bus)) {
> +		/* Checking whether the link is up is the last line of
> +		 * defense, and this check is inherently racy by definition.
> +		 * Sending a PIO request to a downstream device when the link is
> +		 * down causes an unrecoverable error, and a reset of the entire
> +		 * PCIe controller will be needed. We can reduce the likelihood
> +		 * of that unrecoverable error by checking whether the link is
> +		 * up, but we can't completely prevent it because the link may
> +		 * go down between the link-up check and the PIO request.
> +		 */

Looks fine to me.  If Lorenzo or Krzysztof thinks this is ready to go,
maybe they will tidy the comment above, i.e.,

  /*
   * Checking whether ...