PCI: Skip attaching driver in device_add() (58d9a38f) · Commits · 戴 / test

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:

Yinghai Lu <yinghai@kernel.org> Signed-off-by:

Bjorn Helgaas <bhelgaas@google.com> Acked-by:

Rafael J. Wysocki <rafael.j.wysocki@intel.com>

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 */

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