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authorRafael J. Wysocki <rafael.j.wysocki@intel.com>2015-03-20 14:56:19 +0100
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2015-03-20 14:56:19 +0100
commit9e8ce4b96b781b003e3174fbbc62e1d4388c8b8f (patch)
tree3823451bc7aba0d2601ec67bdb9b43a3e51ea2f3 /arch/x86/pci/common.c
parent06e5801b8cb3fc057d88cb4dc03c0b64b2744cda (diff)
downloadlinux-9e8ce4b96b781b003e3174fbbc62e1d4388c8b8f.tar.bz2
Revert "x86/PCI: Refine the way to release PCI IRQ resources"
Commit b4b55cda5874 (Refine the way to release PCI IRQ resources) introduced a regression in the PCI IRQ resource management by causing the IRQ resource of a device, established when pci_enabled_device() is called on a fully disabled device, to be released when the driver is unbound from the device, regardless of the enable_cnt. This leads to the situation that an ill-behaved driver can now make a device unusable to subsequent drivers by an imbalance in their use of pci_enable/disable_device(). That is a serious problem for secondary drivers like vfio-pci, which are innocent of the transgressions of the previous driver. Since the solution of this problem is not immediate and requires further discussion, revert commit b4b55cda5874 and the issue it was supposed to address (a bug related to xen-pciback) will be taken care of in a different way going forward. Reported-by: Alex Williamson <alex.williamson@redhat.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'arch/x86/pci/common.c')
-rw-r--r--arch/x86/pci/common.c34
1 files changed, 6 insertions, 28 deletions
diff --git a/arch/x86/pci/common.c b/arch/x86/pci/common.c
index 3d2612b68694..2fb384724ebb 100644
--- a/arch/x86/pci/common.c
+++ b/arch/x86/pci/common.c
@@ -513,31 +513,6 @@ void __init pcibios_set_cache_line_size(void)
}
}
-/*
- * Some device drivers assume dev->irq won't change after calling
- * pci_disable_device(). So delay releasing of IRQ resource to driver
- * unbinding time. Otherwise it will break PM subsystem and drivers
- * like xen-pciback etc.
- */
-static int pci_irq_notifier(struct notifier_block *nb, unsigned long action,
- void *data)
-{
- struct pci_dev *dev = to_pci_dev(data);
-
- if (action != BUS_NOTIFY_UNBOUND_DRIVER)
- return NOTIFY_DONE;
-
- if (pcibios_disable_irq)
- pcibios_disable_irq(dev);
-
- return NOTIFY_OK;
-}
-
-static struct notifier_block pci_irq_nb = {
- .notifier_call = pci_irq_notifier,
- .priority = INT_MIN,
-};
-
int __init pcibios_init(void)
{
if (!raw_pci_ops) {
@@ -550,9 +525,6 @@ int __init pcibios_init(void)
if (pci_bf_sort >= pci_force_bf)
pci_sort_breadthfirst();
-
- bus_register_notifier(&pci_bus_type, &pci_irq_nb);
-
return 0;
}
@@ -711,6 +683,12 @@ int pcibios_enable_device(struct pci_dev *dev, int mask)
return 0;
}
+void pcibios_disable_device (struct pci_dev *dev)
+{
+ if (!pci_dev_msi_enabled(dev) && pcibios_disable_irq)
+ pcibios_disable_irq(dev);
+}
+
int pci_ext_cfg_avail(void)
{
if (raw_pci_ext_ops)