[PATCH 4.19 112/113] PCI: hv: Add hv_pci_remove_slots() when we unload the driver

From: Greg Kroah-Hartman
Date: Wed May 15 2019 - 07:27:34 EST


From: Dexuan Cui <decui@xxxxxxxxxxxxx>

commit 15becc2b56c6eda3d9bf5ae993bafd5661c1fad1 upstream.

When we unload the pci-hyperv host controller driver, the host does not
send us a PCI_EJECT message.

In this case we also need to make sure the sysfs PCI slot directory is
removed, otherwise a command on a slot file eg:

"cat /sys/bus/pci/slots/2/address"

will trigger a

"BUG: unable to handle kernel paging request"

and, if we unload/reload the driver several times we would end up with
stale slot entries in PCI slot directories in /sys/bus/pci/slots/

root@localhost:~# ls -rtl /sys/bus/pci/slots/
total 0
drwxr-xr-x 2 root root 0 Feb 7 10:49 2
drwxr-xr-x 2 root root 0 Feb 7 10:49 2-1
drwxr-xr-x 2 root root 0 Feb 7 10:51 2-2

Add the missing code to remove the PCI slot and fix the current
behaviour.

Fixes: a15f2c08c708 ("PCI: hv: support reporting serial number as slot information")
Signed-off-by: Dexuan Cui <decui@xxxxxxxxxxxxx>
[lorenzo.pieralisi@xxxxxxx: reformatted the log]
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>
Reviewed-by: Stephen Hemminger <sthemmin@xxxxxxxxxxxxx>
Reviewed-by: Michael Kelley <mikelley@xxxxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
drivers/pci/controller/pci-hyperv.c | 16 ++++++++++++++++
1 file changed, 16 insertions(+)

--- a/drivers/pci/controller/pci-hyperv.c
+++ b/drivers/pci/controller/pci-hyperv.c
@@ -1491,6 +1491,21 @@ static void hv_pci_assign_slots(struct h
}
}

+/*
+ * Remove entries in sysfs pci slot directory.
+ */
+static void hv_pci_remove_slots(struct hv_pcibus_device *hbus)
+{
+ struct hv_pci_dev *hpdev;
+
+ list_for_each_entry(hpdev, &hbus->children, list_entry) {
+ if (!hpdev->pci_slot)
+ continue;
+ pci_destroy_slot(hpdev->pci_slot);
+ hpdev->pci_slot = NULL;
+ }
+}
+
/**
* create_root_hv_pci_bus() - Expose a new root PCI bus
* @hbus: Root PCI bus, as understood by this driver
@@ -2685,6 +2700,7 @@ static int hv_pci_remove(struct hv_devic
pci_lock_rescan_remove();
pci_stop_root_bus(hbus->pci_bus);
pci_remove_root_bus(hbus->pci_bus);
+ hv_pci_remove_slots(hbus);
pci_unlock_rescan_remove();
hbus->state = hv_pcibus_removed;
}