On Wed, Jan 15, 2014 at 02:36:36PM +0100, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
> Subject: powerpc / eeh_driver: Use global PCI rescan-remove locking
>
> Race conditions are theoretically possible between the PCI device
> addition and removal in the PPC64 PCI error recovery driver and
> the generic PCI bus rescan and device removal that can be triggered
> via sysfs.
>
> To avoid those race conditions make PPC64 PCI error recovery driver
> use global PCI rescan-remove locking around PCI device addition and
> removal.
>
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
> ---
>
> The previous version had wrong function names in the last hunk, sorry about
> that.
I replaced the previous version and re-pushed the pci/locking branch,
thanks!
>
> Rafael
>
> ---
> arch/powerpc/kernel/eeh_driver.c | 19 ++++++++++++++++---
> 1 file changed, 16 insertions(+), 3 deletions(-)
>
> Index: linux-pm/arch/powerpc/kernel/eeh_driver.c
> ===================================================================
> --- linux-pm.orig/arch/powerpc/kernel/eeh_driver.c
> +++ linux-pm/arch/powerpc/kernel/eeh_driver.c
> @@ -369,7 +369,9 @@ static void *eeh_rmv_device(void *data,
> edev->mode |= EEH_DEV_DISCONNECTED;
> (*removed)++;
>
> + pci_lock_rescan_remove();
> pci_stop_and_remove_bus_device(dev);
> + pci_unlock_rescan_remove();
>
> return NULL;
> }
> @@ -416,10 +418,13 @@ static int eeh_reset_device(struct eeh_p
> * into pcibios_add_pci_devices().
> */
> eeh_pe_state_mark(pe, EEH_PE_KEEP);
> - if (bus)
> + if (bus) {
> + pci_lock_rescan_remove();
> pcibios_remove_pci_devices(bus);
> - else if (frozen_bus)
> + pci_unlock_rescan_remove();
> + } else if (frozen_bus) {
> eeh_pe_dev_traverse(pe, eeh_rmv_device, &removed);
> + }
>
> /* Reset the pci controller. (Asserts RST#; resets config space).
> * Reconfigure bridges and devices. Don't try to bring the system
> @@ -429,6 +434,8 @@ static int eeh_reset_device(struct eeh_p
> if (rc)
> return rc;
>
> + pci_lock_rescan_remove();
> +
> /* Restore PE */
> eeh_ops->configure_bridge(pe);
> eeh_pe_restore_bars(pe);
> @@ -462,6 +469,7 @@ static int eeh_reset_device(struct eeh_p
> pe->tstamp = tstamp;
> pe->freeze_count = cnt;
>
> + pci_unlock_rescan_remove();
> return 0;
> }
>
> @@ -618,8 +626,11 @@ perm_error:
> eeh_pe_dev_traverse(pe, eeh_report_failure, NULL);
>
> /* Shut down the device drivers for good. */
> - if (frozen_bus)
> + if (frozen_bus) {
> + pci_lock_rescan_remove();
> pcibios_remove_pci_devices(frozen_bus);
> + pci_unlock_rescan_remove();
> + }
> }
>
> static void eeh_handle_special_event(void)
> @@ -692,6 +703,7 @@ static void eeh_handle_special_event(voi
> if (rc == 2 || rc == 1)
> eeh_handle_normal_event(pe);
> else {
> + pci_lock_rescan_remove();
> list_for_each_entry_safe(hose, tmp,
> &hose_list, list_node) {
> phb_pe = eeh_phb_pe_get(hose);
> @@ -703,6 +715,7 @@ static void eeh_handle_special_event(voi
> eeh_pe_dev_traverse(pe, eeh_report_failure, NULL);
> pcibios_remove_pci_devices(bus);
> }
> + pci_unlock_rescan_remove();
> }
> }
>
>
> --
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