On Friday, January 31, 2014 12:59:06 AM Rafael J. Wysocki wrote: > On Thursday, January 30, 2014 03:39:02 PM Yinghai Lu wrote: > > On Thu, Jan 30, 2014 at 3:39 PM, Rafael J. Wysocki <rjw@xxxxxxxxxxxxx> wrote: > > > On Thursday, January 30, 2014 08:56:05 AM Yinghai Lu wrote: > > >> > > >> --047d7b5d2ea4eb937804f132eedf > > >> Content-Type: text/plain; charset=ISO-8859-1 > > >> > > >> >> The latest mainline kernel "hangs" when Thunderbolt devices are > > >> >> hot-unplugged to the system. I can't see any oops but after hot-unplug I'm > > >> >> getting huge amounts of messages like: > > >> >> > > >> >> [ 352.717001] pci 0000:02:00.0: PME# disabled > > >> >> [ 352.717011] pci 0000:02:00.0: PME# disabled > > >> >> [ 352.717021] pci 0000:02:00.0: PME# disabled > > >> >> [ 352.717032] pci 0000:02:00.0: PME# disabled > > >> >> [ 352.717041] pci 0000:02:00.0: PME# disabled > > >> >> [ 352.717051] pci 0000:02:00.0: PME# disabled > > >> >> [ 352.717061] pci 0000:02:00.0: PME# disabled > > >> >> [ 352.717070] pci 0000:02:00.0: PME# disabled > > >> >> [ 352.717083] pci 0000:02:00.0: PME# disabled > > >> >> [ 352.717094] pci 0000:02:00.0: PME# disabled > > >> >> [ 352.717104] pci 0000:02:00.0: PME# disabled > > >> >> [ 352.717113] pci 0000:02:00.0: PME# disabled > > >> >> [ 352.717124] pci 0000:02:00.0: PME# disabled > > >> >> [ 352.717133] pci 0000:02:00.0: PME# disabled > > >> >> [ 352.717143] pci 0000:02:00.0: PME# disabled > > >> >> [ 352.717153] pci 0000:02:00.0: PME# disabled > > >> >> [ 352.717162] pci 0000:02:00.0: PME# disabled > > >> > > > >> > that mean pci_stop_dev() get called again and again ? > > >> > > >> please check if attached patch could help. > > > > > > Well, it looks like what happens is an endless loop in > > > acpiphp_glue.c:disable_slot(). > > > > > > dev_in_slot() returns the first device in the list, so > > > pci_stop_and_remove_bus_device() is called for it, but it > > > doesn't remove the device from bus->devices any more, so > > > dev_in_slot() will return the same device next time and > > > so on forever. > > > > > ... > > > > > > So the above won't help in my opinion. > > > > > > I wonder, however, if this patch helps instead: > > > > > > https://patchwork.kernel.org/patch/3540701/ > > > > > > I thought it would be 3.15 material, but it very well can go in earlier if > > > it happens to address this particular problem. > > > > Agree, that should fix the problem. > > > > but please use list_for_each_entry_safe_reverse > > instead. > > OK, I will. Mika, below is an updated patch to try. --- From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> Subject: ACPI / hotplug / PCI: Simplify disable_slot() After recent PCI core changes related to the rescan/remove locking, the ACPIPHP's disable_slot() function is only called under the general PCI rescan/remove lock, so it doesn't have to use dev_in_slot() any more to avoid race conditions. Make it simply walk the devices on the bus and drop the ones in the slot being disabled and drop dev_in_slot() which has no more users. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> --- drivers/pci/hotplug/acpiphp_glue.c | 28 +++++----------------------- 1 file changed, 5 insertions(+), 23 deletions(-) Index: linux-pm/drivers/pci/hotplug/acpiphp_glue.c =================================================================== --- linux-pm.orig/drivers/pci/hotplug/acpiphp_glue.c +++ linux-pm/drivers/pci/hotplug/acpiphp_glue.c @@ -604,32 +604,15 @@ static void __ref enable_slot(struct acp } } -/* return first device in slot, acquiring a reference on it */ -static struct pci_dev *dev_in_slot(struct acpiphp_slot *slot) -{ - struct pci_bus *bus = slot->bus; - struct pci_dev *dev; - struct pci_dev *ret = NULL; - - down_read(&pci_bus_sem); - list_for_each_entry(dev, &bus->devices, bus_list) - if (PCI_SLOT(dev->devfn) == slot->device) { - ret = pci_dev_get(dev); - break; - } - up_read(&pci_bus_sem); - - return ret; -} - /** * disable_slot - disable a slot * @slot: ACPI PHP slot */ static void disable_slot(struct acpiphp_slot *slot) { + struct pci_bus *bus = slot->bus; + struct pci_dev *dev, *prev; struct acpiphp_func *func; - struct pci_dev *pdev; /* * enable_slot() enumerates all functions in this device via @@ -637,10 +620,9 @@ static void disable_slot(struct acpiphp_ * methods (_EJ0, etc.) or not. Therefore, we remove all functions * here. */ - while ((pdev = dev_in_slot(slot))) { - pci_stop_and_remove_bus_device(pdev); - pci_dev_put(pdev); - } + list_for_each_entry_safe_reverse(dev, prev, &bus->devices, bus_list) + if (PCI_SLOT(dev->devfn) == slot->device) + pci_stop_and_remove_bus_device(dev); list_for_each_entry(func, &slot->funcs, sibling) acpiphp_bus_trim(func_to_handle(func)); -- 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
