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Commit 58d9a38f authored by Yinghai Lu's avatar Yinghai Lu Committed by Bjorn Helgaas
Browse files

PCI: Skip attaching driver in device_add() 



We want to add PCI devices to the device tree as early as possible but
delay attaching drivers.

device_add() adds a device to the device hierarchy and (via
device_attach()) attaches a matching driver and calls its .probe() method.
We want to separate adding the device to the hierarchy from attaching the
driver.

This patch does that by adding "match_driver" in struct pci_dev.  When
false, we return failure from pci_bus_match(), which makes device_attach()
believe there's no matching driver.

Later, we set "match_driver = true" and call device_attach() again, which
now attaches the driver and calls its .probe() method.

[bhelgaas: changelog, explicitly init dev->match_driver,
fold device_attach() call into pci_bus_add_device()]
Signed-off-by: default avatarYinghai Lu <yinghai@kernel.org>
Signed-off-by: default avatarBjorn Helgaas <bhelgaas@google.com>
Acked-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent d59f53bc

drivers/pci/bus.c

+5 −0
Original line number Diff line number Diff line
@@ -177,10 +177,15 @@ int pci_bus_add_device(struct pci_dev *dev) 
	if (retval)

		return retval;



	dev->match_driver = false;

	retval = device_add(&dev->dev);

	if (retval)

		return retval;



	dev->match_driver = true;

	retval = device_attach(&dev->dev);

	WARN_ON(retval < 0);



	dev->is_added = 1;

	pci_proc_attach_device(dev);

	pci_create_sysfs_dev_files(dev);

drivers/pci/pci-driver.c

+5 −1
Original line number Diff line number Diff line
@@ -1186,9 +1186,13 @@ pci_dev_driver(const struct pci_dev *dev) 
static int pci_bus_match(struct device *dev, struct device_driver *drv)

{

	struct pci_dev *pci_dev = to_pci_dev(dev);

	struct pci_driver *pci_drv = to_pci_driver(drv);

	struct pci_driver *pci_drv;

	const struct pci_device_id *found_id;



	if (!pci_dev->match_driver)

		return 0;



	pci_drv = to_pci_driver(drv);

	found_id = pci_match_device(pci_drv, pci_dev);

	if (found_id)

		return 1;

include/linux/pci.h

+1 −0
Original line number Diff line number Diff line
@@ -286,6 +286,7 @@ struct pci_dev { 
	unsigned int	irq;

	struct resource resource[DEVICE_COUNT_RESOURCE]; /* I/O and memory regions + expansion ROMs */



	bool match_driver;		/* Skip attaching driver */

	/* These fields are used by common fixups */

	unsigned int	transparent:1;	/* Transparent PCI bridge */

	unsigned int	multifunction:1;/* Part of multi-function device */