4.9-stable review patch. If anyone has any objections, please let me know.
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From: Long Li longli@microsoft.com
[ Upstream commit d3a78d8bf759d8848339dcc367c4c1678b57a08b ]
hv_pci_devices_present() is called in hv_pci_remove() when we remove a PCI device from the host, e.g., by disabling SR-IOV 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 bus state hv_pcibus_removed, we can avoid this situation.
Reported-by: Xiaofeng Wang xiaofwan@redhat.com Signed-off-by: Long Li longli@microsoft.com Signed-off-by: Bjorn Helgaas bhelgaas@google.com Acked-by: K. Y. Srinivasan kys@microsoft.com Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/pci/host/pci-hyperv.c | 20 +++++++++++++++++--- 1 file changed, 17 insertions(+), 3 deletions(-)
--- a/drivers/pci/host/pci-hyperv.c +++ b/drivers/pci/host/pci-hyperv.c @@ -351,6 +351,7 @@ enum hv_pcibus_state { hv_pcibus_init = 0, hv_pcibus_probed, hv_pcibus_installed, + hv_pcibus_removed, hv_pcibus_maximum };
@@ -1489,13 +1490,24 @@ static void pci_devices_present_work(str 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); @@ -2170,6 +2182,7 @@ static int hv_pci_probe(struct hv_device 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 @@ -2312,6 +2325,7 @@ static int hv_pci_remove(struct hv_devic pci_stop_root_bus(hbus->pci_bus); pci_remove_root_bus(hbus->pci_bus); pci_unlock_rescan_remove(); + hbus->state = hv_pcibus_removed; }
ret = hv_send_resources_released(hdev);