| Message ID | CAE9FiQXD7hvt0cUYMzvq0r6CbZn=iJZc7BHRaF2nACbG7qwuBQ@mail.gmail.com |
|---|---|
| State | Superseded |
| Headers | show |
On Wed, Jun 18, 2014 at 1:39 AM, Yinghai Lu <yinghai@kernel.org> wrote: > On Tue, Jun 17, 2014 at 3:16 PM, Bjorn Helgaas <bhelgaas@google.com> wrote: >> [+cc Yinghai] >> >> On Mon, Jun 09, 2014 at 10:45:30PM +0200, Andreas Noever wrote: >>> The problem can be reproduced by having two sibling hotplug bridges A >>> and B. The problem will occour if the parent of A and B does not have >>> enough resources to satisfy window allocations for B during a hotplug >>> event. > >> I don't understand how all this works either. Yinghai? >> >> We definitely don't want to release resources that are already in use. Can >> you review and ack or nack this? > > Hi Andreas, > > Can you check if attached patch fix the problem on your test case? It seems to fix the testcase (no unwanted resources are released). But why do you reassign bus and not just skip the top level bridge? If one of the allocations below bridge failed then a resource of that device will be in fail_res and bridge->subordinate will get released anyways? Also by not removing fail_res from the list you trigger the code in the next loop for the top level bridge (in particular the res->flags = 0 line looks dangerous). Could you explain why this function attempts to assign resources two times? In which scenario will a second attempt be successful? Thanks, Andreas > In some case, if we can not assign pref mmio properly for the bridge, > we may need to even clear non-pref mmio for the bridge. > > Thanks > > Yinghai -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Subject: [PATCH] pci: Don't release sibiling bridge resources On hotplug case, we should not touch sibling bridges that is out side of the slots. Signed-off-by: Yinghai Lu <yinghai@kernel.org> --- drivers/pci/setup-bus.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) Index: linux-2.6/drivers/pci/setup-bus.c =================================================================== --- linux-2.6.orig/drivers/pci/setup-bus.c +++ linux-2.6/drivers/pci/setup-bus.c @@ -1676,10 +1676,16 @@ again: * Try to release leaf bridge's resources that doesn't fit resource of * child device under that bridge */ - list_for_each_entry(fail_res, &fail_head, list) - pci_bus_release_bridge_resources(fail_res->dev->bus, + list_for_each_entry(fail_res, &fail_head, list) { + struct pci_bus *bus = fail_res->dev->bus; + + if (fail_res->dev == bridge) + bus = bridge->subordinate; + + pci_bus_release_bridge_resources(bus, fail_res->flags & type_mask, whole_subtree); + } /* restore size and flags */ list_for_each_entry(fail_res, &fail_head, list) {