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Commit b97ea289 authored by Yijing Wang's avatar Yijing Wang Committed by Bjorn Helgaas
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PCI: Assign resources before drivers claim devices (pci_scan_root_bus()) 



Previously, pci_scan_root_bus() created a root PCI bus, enumerated the
devices on it, and called pci_bus_add_devices(), which made the devices
available for drivers to claim them.

Most callers assigned resources to devices after pci_scan_root_bus()
returns, which may be after drivers have claimed the devices.  This is
incorrect; the PCI core should not change device resources while a driver
is managing the device.

Remove pci_bus_add_devices() from pci_scan_root_bus() and do it after any
resource assignment in the callers.

Note that ARM's pci_common_init_dev() already called pci_bus_add_devices()
after pci_scan_root_bus(), so we only need to remove the first call:

  pci_common_init_dev
    pcibios_init_hw
      pci_scan_root_bus
        pci_bus_add_devices        # first call
    pci_bus_assign_resources
    pci_bus_add_devices            # second call

[bhelgaas: changelog, drop "root_bus" var in alpha common_init_pci(),
return failure earlier in mn10300, add "return" in x86 pcibios_scan_root(),
return early if xtensa platform_pcibios_fixup() fails]
Signed-off-by: default avatarYijing Wang <wangyijing@huawei.com>
Signed-off-by: default avatarBjorn Helgaas <bhelgaas@google.com>
CC: Richard Henderson <rth@twiddle.net>
CC: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
CC: Matt Turner <mattst88@gmail.com>
CC: David Howells <dhowells@redhat.com>
CC: Tony Luck <tony.luck@intel.com>
CC: Michal Simek <monstr@monstr.eu>
CC: Ralf Baechle <ralf@linux-mips.org>
CC: Koichi Yasutake <yasutake.koichi@jp.panasonic.com>
CC: Sebastian Ott <sebott@linux.vnet.ibm.com>
CC: "David S. Miller" <davem@davemloft.net>
CC: Chris Metcalf <cmetcalf@ezchip.com>
CC: Chris Zankel <chris@zankel.net>
CC: Max Filippov <jcmvbkbc@gmail.com>
CC: Thomas Gleixner <tglx@linutronix.de>
parent c90570d9

arch/alpha/kernel/pci.c

+7 −0
Original line number Diff line number Diff line
@@ -338,6 +338,8 @@ common_init_pci(void) 


		bus = pci_scan_root_bus(NULL, next_busno, alpha_mv.pci_ops,

					hose, &resources);

		if (!bus)

			continue;

		hose->bus = bus;

		hose->need_domain_info = need_domain_info;

		next_busno = bus->busn_res.end + 1;
@@ -353,6 +355,11 @@ common_init_pci(void) 


	pci_assign_unassigned_resources();

	pci_fixup_irqs(alpha_mv.pci_swizzle, alpha_mv.pci_map_irq);

	for (hose = hose_head; hose; hose = hose->next) {

		bus = hose->bus;

		if (bus)

			pci_bus_add_devices(bus);

	}

}

arch/frv/mb93090-mb00/pci-vdk.c

+5 −1
Original line number Diff line number Diff line
@@ -316,6 +316,7 @@ void pcibios_fixup_bus(struct pci_bus *bus) 


int __init pcibios_init(void)

{

	struct pci_bus *bus;

	struct pci_ops *dir = NULL;

	LIST_HEAD(resources);
@@ -383,12 +384,15 @@ int __init pcibios_init(void) 
	printk("PCI: Probing PCI hardware\n");

	pci_add_resource(&resources, &pci_ioport_resource);

	pci_add_resource(&resources, &pci_iomem_resource);

	pci_scan_root_bus(NULL, 0, pci_root_ops, NULL, &resources);

	bus = pci_scan_root_bus(NULL, 0, pci_root_ops, NULL, &resources);



	pcibios_irq_init();

	pcibios_fixup_irqs();

	pcibios_resource_survey();

	if (!bus)

		return 0;



	pci_bus_add_devices(bus);

	return 0;

}

arch/ia64/sn/kernel/io_init.c

+2 −0
Original line number Diff line number Diff line
@@ -271,7 +271,9 @@ sn_pci_controller_fixup(int segment, int busnum, struct pci_bus *bus) 
 	if (bus == NULL) {

		kfree(res);

		kfree(controller);

		return;

	}

	pci_bus_add_devices(bus);

}



/*

arch/microblaze/pci/pci-common.c

+4 −0
Original line number Diff line number Diff line
@@ -1382,6 +1382,10 @@ static int __init pcibios_init(void) 


	/* Call common code to handle resource allocation */

	pcibios_resource_survey();

	list_for_each_entry_safe(hose, tmp, &hose_list, list_node) {

		if (hose->bus)

			pci_bus_add_devices(hose->bus);

	}



	return 0;

}

arch/mips/pci/pci.c

+1 −0
Original line number Diff line number Diff line
@@ -114,6 +114,7 @@ static void pcibios_scanbus(struct pci_controller *hose) 
			pci_bus_size_bridges(bus);

			pci_bus_assign_resources(bus);

		}

		pci_bus_add_devices(bus);

	}

}