Re: [PATCH v7 05/13] PCI/ERR: Use "bridge" for clarity in pcie_do_recovery()

From: Jonathan Cameron
Date: Thu Oct 01 2020 - 05:08:44 EST


On Wed, 30 Sep 2020 14:58:12 -0700
Sean V Kelley <seanvk.dev@xxxxxxxxxxxxxxxx> wrote:

> From: Sean V Kelley <sean.v.kelley@xxxxxxxxx>
>
> The term "dev" is being applied to root ports, switch
> upstream ports, switch downstream ports, and the upstream
> ports on endpoints. While endpoint upstream ports don't have
> subordinate buses, a generic term such as "bridge" may be used

This sentence is a bit confusing. The bit before the comma
seems only slightly connected. Perhaps 2 sentences?

> for something with a subordinate bus. The current conditional
> logic in pcie_do_recovery() would also benefit from some
> simplification with use of pci_upstream_bridge() in place of
> dev->bus->self. Reverse the pcie_do_recovery() conditional logic
> and replace use of "dev" with "bridge" for greater clarity.
>
> Suggested-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
> Signed-off-by: Sean V Kelley <sean.v.kelley@xxxxxxxxx>

Acked-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>

> ---
> drivers/pci/pcie/err.c | 20 +++++++++++++-------
> 1 file changed, 13 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/pci/pcie/err.c b/drivers/pci/pcie/err.c
> index 950612342f1c..c6922c099c76 100644
> --- a/drivers/pci/pcie/err.c
> +++ b/drivers/pci/pcie/err.c
> @@ -152,16 +152,22 @@ pci_ers_result_t pcie_do_recovery(struct pci_dev *dev,
> {
> pci_ers_result_t status = PCI_ERS_RESULT_CAN_RECOVER;
> struct pci_bus *bus;
> + struct pci_dev *bridge;
> + int type;
>
> /*
> - * Error recovery runs on all subordinates of the first downstream port.
> - * If the downstream port detected the error, it is cleared at the end.
> + * Error recovery runs on all subordinates of the first downstream
> + * bridge. If the downstream bridge detected the error, it is
> + * cleared at the end.
> */
> - if (!(pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT ||
> - pci_pcie_type(dev) == PCI_EXP_TYPE_DOWNSTREAM))
> - dev = dev->bus->self;
> - bus = dev->subordinate;
> -
> + type = pci_pcie_type(dev);
> + if (type == PCI_EXP_TYPE_ROOT_PORT ||
> + type == PCI_EXP_TYPE_DOWNSTREAM)
> + bridge = dev;
> + else
> + bridge = pci_upstream_bridge(dev);
> +
> + bus = bridge->subordinate;
> pci_dbg(dev, "broadcast error_detected message\n");
> if (state == pci_channel_io_frozen) {
> pci_walk_bus(bus, report_frozen_detected, &status);