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x86, irq: Keep balance of IOAPIC pin reference count

Browse source 
To keep balance of IOAPIC pin reference count, we need to protect
pirq_enable_irq(), acpi_pci_irq_enable() and intel_mid_pci_irq_enable()
from reentrance. There are two cases which will cause reentrance.

The first case is caused by suspend/hibernation. If pcibios_disable_irq
is called during suspending/hibernating, we don't release the assigned
IRQ number, otherwise it may break the suspend/hibernation. So late when
pcibios_enable_irq is called during resume, we shouldn't allocate IRQ
number again.

The second case is that function acpi_pci_irq_enable() may be called
twice for PCI devices present at boot time as below:
1) pci_acpi_init()
	--> acpi_pci_irq_enable() if pci_routeirq is true
2) pci_enable_device()
	--> pcibios_enable_device()
		--> acpi_pci_irq_enable()
We can't kill kernel parameter pci_routeirq yet because it's still
needed for debugging purpose.

So flag irq_managed is introduced to track whether IRQ number is
assigned by OS and to protect pirq_enable_irq(), acpi_pci_irq_enable()
and intel_mid_pci_irq_enable() from reentrance.

Signed-off-by: Jiang Liu <[email protected]>
Cc: Konrad Rzeszutek Wilk <[email protected]>
Cc: Tony Luck <[email protected]>
Cc: Joerg Roedel <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: Benjamin Herrenschmidt <[email protected]>
Cc: Rafael J. Wysocki <[email protected]>
Cc: Bjorn Helgaas <[email protected]>
Cc: Randy Dunlap <[email protected]>
Cc: Yinghai Lu <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Len Brown <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Thomas Gleixner <[email protected]>
This commit is contained in:
Jiang Liu 2014-10-27 13:21:42 +08:00 • committed by Thomas Gleixner
commit cffe0a2b5a
4 changed files with 25 additions and 4 deletions
Download patch file Download diff file Expand all files Collapse all files

11
drivers/acpi/pci_irq.c
View file

@ -413,6 +413,9 @@ int acpi_pci_irq_enable(struct pci_dev *dev)
return 0;
}
if (dev->irq_managed && dev->irq > 0)
return 0;
entry = acpi_pci_irq_lookup(dev, pin);
if (!entry) {
/*
@ -456,6 +459,7 @@ int acpi_pci_irq_enable(struct pci_dev *dev)
return rc;
}
dev->irq = rc;
dev->irq_managed = 1;
if (link)
snprintf(link_desc, sizeof(link_desc), " -> Link[%s]", link);
@ -478,7 +482,7 @@ void acpi_pci_irq_disable(struct pci_dev *dev)
u8 pin;
pin = dev->pin;
if (!pin)
if (!pin || !dev->irq_managed || dev->irq <= 0)
return;
/* Keep IOAPIC pin configuration when suspending */
@ -506,6 +510,9 @@ void acpi_pci_irq_disable(struct pci_dev *dev)
*/
dev_dbg(&dev->dev, "PCI INT %c disabled\n", pin_name(pin));
if (gsi >= 0 && dev->irq > 0)
if (gsi >= 0) {
acpi_unregister_gsi(gsi);
dev->irq = 0;
dev->irq_managed = 0;
}
}