From bec7ec71dbeb92dc830719be7c11f87786830863 Mon Sep 17 00:00:00 2001
From: Amos Kong <kongjianjun@gmail.com>
Date: Tue, 22 May 2012 18:35:11 +0000
Subject: [PATCH 2/2] PCI: acpiphp: remove all functions in slot, even without ACPI _EJx
When we add a device with acpiphp, we enumerate all functions in the
slot with pci_scan_slot(), regardless of whether they have associated
ACPI methods such as _EJ0.
When removing the device, we previously removed only the functions
with those ACPI methods. This patch makes the remove symmetric with the
add: we remove all functions in the slot, whether they have associated
ACPI methods or not.
With qemu-kvm and SeaBIOS, we can build a multi-function device where
only function 0 has _EJ0 and _ADR (see bugzilla below). Removing and
re-adding that device works correctly with Windows guests. This patch
makes it also work in Linux guests.
[bhelgaas: restructure loop iteration, pull out of slot->funcs loop]
Reference: https://bugzilla.kernel.org/show_bug.cgi?id=43219
Signed-off-by: Amos Kong <kongjianjun@gmail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
---
v7: keep that pci_bus_sem operation pair on return path
---
drivers/pci/hotplug/acpiphp_glue.c | 40 +++++++++++++++++++++++++++---------
1 files changed, 30 insertions(+), 10 deletions(-)
@@ -878,6 +878,22 @@ static void disable_bridges(struct pci_bus *bus)
}
}
+/* 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->bridge->pci_bus;
+ struct pci_dev *dev;
+ int 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);
+ up_read(&pci_bus_sem);
+
+ return ret;
+}
+
/**
* disable_device - disable a slot
* @slot: ACPI PHP slot
@@ -902,18 +918,22 @@ static int disable_device(struct acpiphp_slot *slot)
(u32)1, NULL, NULL);
func->bridge = NULL;
}
+ }
- pdev = pci_get_slot(slot->bridge->pci_bus,
- PCI_DEVFN(slot->device, func->function));
- if (pdev) {
- pci_stop_bus_device(pdev);
- if (pdev->subordinate) {
- disable_bridges(pdev->subordinate);
- pci_disable_device(pdev);
- }
- __pci_remove_bus_device(pdev);
- pci_dev_put(pdev);
+ /*
+ * enable_device() enumerates all functions in this device via
+ * pci_scan_slot(), whether they have associated ACPI hotplug
+ * methods (_EJ0, etc.) or not. Therefore, we remove all functions
+ * here.
+ */
+ while ((pdev = dev_in_slot(slot))) {
+ pci_stop_bus_device(pdev);
+ if (pdev->subordinate) {
+ disable_bridges(pdev->subordinate);
+ pci_disable_device(pdev);
}
+ __pci_remove_bus_device(pdev);
+ pci_dev_put(pdev);
}
list_for_each_entry(func, &slot->funcs, sibling) {
--
1.7.1