On Fri, Oct 28, 2016 at 06:58:15PM -0400, Keith Busch wrote:
> This adds a new state for devices that were once in the system, but
> unexpectedly removed. This is so device tear down functions can observe
> the device is not accessible so it may skip attempting to initialize
> the hardware.
>
> The pciehp and pcie-dpc drivers are aware of when the link is down,
> so these explicitly set this flag when its handlers detect the device
> is gone.
>
> Signed-off-by: Keith Busch <keith.busch@xxxxxxxxx>
Reviewed-by: Lukas Wunner <lukas@xxxxxxxxx>
I'll send a follow-up patch in a few minutes which leverages the
is_removed flag to fix a soft lockup on surprise removal of the
Apple Thunderbolt Gigabit Ethernet adapter.
Thanks,
Lukas
> ---
> drivers/pci/hotplug/pciehp_pci.c | 5 +++++
> drivers/pci/pcie/pcie-dpc.c | 4 ++++
> include/linux/pci.h | 7 +++++++
> 3 files changed, 16 insertions(+)
>
> diff --git a/drivers/pci/hotplug/pciehp_pci.c b/drivers/pci/hotplug/pciehp_pci.c
> index 9e69403..7560961 100644
> --- a/drivers/pci/hotplug/pciehp_pci.c
> +++ b/drivers/pci/hotplug/pciehp_pci.c
> @@ -109,6 +109,11 @@ int pciehp_unconfigure_device(struct slot *p_slot)
> break;
> }
> }
> + if (!presence) {
> + pci_set_removed(dev, NULL);
> + if (pci_has_subordinate(dev))
> + pci_walk_bus(dev->subordinate, pci_set_removed, NULL);
> + }
> pci_stop_and_remove_bus_device(dev);
> /*
> * Ensure that no new Requests will be generated from
> diff --git a/drivers/pci/pcie/pcie-dpc.c b/drivers/pci/pcie/pcie-dpc.c
> index 9811b14..7818c88 100644
> --- a/drivers/pci/pcie/pcie-dpc.c
> +++ b/drivers/pci/pcie/pcie-dpc.c
> @@ -14,6 +14,7 @@
> #include <linux/init.h>
> #include <linux/pci.h>
> #include <linux/pcieport_if.h>
> +#include "../pci.h"
>
> struct dpc_dev {
> struct pcie_device *dev;
> @@ -46,6 +47,9 @@ static void interrupt_event_handler(struct work_struct *work)
> list_for_each_entry_safe_reverse(dev, temp, &parent->devices,
> bus_list) {
> pci_dev_get(dev);
> + pci_set_removed(dev, NULL);
> + if (pci_has_subordinate(dev))
> + pci_walk_bus(dev->subordinate, pci_set_removed, NULL);
> pci_stop_and_remove_bus_device(dev);
> pci_dev_put(dev);
> }
> diff --git a/include/linux/pci.h b/include/linux/pci.h
> index 0e49f70..2115d19 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -341,6 +341,7 @@ struct pci_dev {
> unsigned int multifunction:1;/* Part of multi-function device */
> /* keep track of device state */
> unsigned int is_added:1;
> + unsigned int is_removed:1; /* device was surprise removed */
> unsigned int is_busmaster:1; /* device is busmaster */
> unsigned int no_msi:1; /* device may not use msi */
> unsigned int no_64bit_msi:1; /* device may only use 32-bit MSIs */
> @@ -417,6 +418,12 @@ static inline int pci_channel_offline(struct pci_dev *pdev)
> return (pdev->error_state != pci_channel_io_normal);
> }
>
> +static inline int pci_set_removed(struct pci_dev *pdev, void *unused)
> +{
> + pdev->is_removed = 1;
> + return 0;
> +}
> +
> struct pci_host_bridge {
> struct device dev;
> struct pci_bus *bus; /* root bus */
> --
> 2.7.2
--
To unsubscribe from this list: send the line "unsubscribe linux-pci" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
