On Thu, Mar 23, 2017 at 02:58:10PM -0700, Long Li wrote:
> From: Long Li <longli@xxxxxxxxxxxxx>
>
> hv_pci_devices_present is called in hv_pci_remove when we remove a PCI
> device from host (e.g. by disabling SRIOV on a device). In hv_pci_remove,
> the bus is already removed before the call, so we don't need to rescan the
> bus in the workqueue scheduled from hv_pci_devices_present.
>
> By introducing status hv_pcibus_removed, we can avoid this situation.
>
> Signed-off-by: Long Li <longli@xxxxxxxxxxxxx>
> Reported-by: Xiaofeng Wang <xiaofwan@xxxxxxxxxx>
> Acked-by: K. Y. Srinivasan <kys@xxxxxxxxxxxxx>
Applied both patches to pci/host-hv for v4.12, thanks! They both applied
perfectly :)
> ---
> drivers/pci/host/pci-hyperv.c | 20 +++++++++++++++++---
> 1 file changed, 17 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/pci/host/pci-hyperv.c b/drivers/pci/host/pci-hyperv.c
> index ada9856..39fafda 100644
> --- a/drivers/pci/host/pci-hyperv.c
> +++ b/drivers/pci/host/pci-hyperv.c
> @@ -350,6 +350,7 @@ enum hv_pcibus_state {
> hv_pcibus_init = 0,
> hv_pcibus_probed,
> hv_pcibus_installed,
> + hv_pcibus_removed,
> hv_pcibus_maximum
> };
>
> @@ -1504,13 +1505,24 @@ static void pci_devices_present_work(struct work_struct *work)
> put_pcichild(hpdev, hv_pcidev_ref_initial);
> }
>
> - /* Tell the core to rescan bus because there may have been changes. */
> - if (hbus->state == hv_pcibus_installed) {
> + switch(hbus->state) {
> + case hv_pcibus_installed:
> + /*
> + * Tell the core to rescan bus
> + * because there may have been changes.
> + */
> pci_lock_rescan_remove();
> pci_scan_child_bus(hbus->pci_bus);
> pci_unlock_rescan_remove();
> - } else {
> + break;
> +
> + case hv_pcibus_init:
> + case hv_pcibus_probed:
> survey_child_resources(hbus);
> + break;
> +
> + default:
> + break;
> }
>
> up(&hbus->enum_sem);
> @@ -2185,6 +2197,7 @@ static int hv_pci_probe(struct hv_device *hdev,
> hbus = kzalloc(sizeof(*hbus), GFP_KERNEL);
> if (!hbus)
> return -ENOMEM;
> + hbus->state = hv_pcibus_init;
>
> /*
> * The PCI bus "domain" is what is called "segment" in ACPI and
> @@ -2348,6 +2361,7 @@ static int hv_pci_remove(struct hv_device *hdev)
> pci_stop_root_bus(hbus->pci_bus);
> pci_remove_root_bus(hbus->pci_bus);
> pci_unlock_rescan_remove();
> + hbus->state = hv_pcibus_removed;
> }
>
> hv_pci_bus_exit(hdev);
> --
> 2.7.4
>
