Commit cecf4864 authored by Paul Mackerras's avatar Paul Mackerras Committed by Greg Kroah-Hartman
Browse files

[PATCH] PCI: Add pci_walk_bus function to PCI core (nonrecursive) 



The PCI error recovery infrastructure needs to be able to contact all
the drivers affected by a PCI error event, which may mean traversing
all the devices under a given PCI-PCI bridge.  This patch adds a
function to the PCI core that traverses all the PCI devices on a PCI
bus and under any PCI-PCI bridges on that bus (and so on), calling a
given function for each device.  This provides a way for the error
recovery code to iterate through all devices that are affected by an
error event.

This version is not implemented as a recursive function.  Instead,
when we reach a PCI-PCI bridge, we set the pointers to start doing the
devices on the bus under the bridge, and when we reach the end of a
bus's devices, we use the bus->self pointer to go back up to the next
higher bus and continue doing its devices.

Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 1d2450a4

drivers/pci/bus.c

+48 −0
Original line number Diff line number Diff line
@@ -151,6 +151,54 @@ void pci_enable_bridges(struct pci_bus *bus) 
	}

}



/** pci_walk_bus - walk devices on/under bus, calling callback.

 *  @top      bus whose devices should be walked

 *  @cb       callback to be called for each device found

 *  @userdata arbitrary pointer to be passed to callback.

 *

 *  Walk the given bus, including any bridged devices

 *  on buses under this bus.  Call the provided callback

 *  on each device found.

 */

void pci_walk_bus(struct pci_bus *top, void (*cb)(struct pci_dev *, void *),

		  void *userdata)

{

	struct pci_dev *dev;

	struct pci_bus *bus;

	struct list_head *next;



	bus = top;

	spin_lock(&pci_bus_lock);

	next = top->devices.next;

	for (;;) {

		if (next == &bus->devices) {

			/* end of this bus, go up or finish */

			if (bus == top)

				break;

			next = bus->self->bus_list.next;

			bus = bus->self->bus;

			continue;

		}

		dev = list_entry(next, struct pci_dev, bus_list);

		pci_dev_get(dev);

		if (dev->subordinate) {

			/* this is a pci-pci bridge, do its devices next */

			next = dev->subordinate->devices.next;

			bus = dev->subordinate;

		} else

			next = dev->bus_list.next;

		spin_unlock(&pci_bus_lock);



		/* Run device routines with the bus unlocked */

		cb(dev, userdata);



		spin_lock(&pci_bus_lock);

		pci_dev_put(dev);

	}

	spin_unlock(&pci_bus_lock);

}

EXPORT_SYMBOL_GPL(pci_walk_bus);



EXPORT_SYMBOL(pci_bus_alloc_resource);

EXPORT_SYMBOL_GPL(pci_bus_add_device);

EXPORT_SYMBOL(pci_bus_add_devices);

include/linux/pci.h

+3 −0
Original line number Diff line number Diff line
@@ -434,6 +434,9 @@ const struct pci_device_id *pci_match_device(struct pci_driver *drv, struct pci_ 
const struct pci_device_id *pci_match_id(const struct pci_device_id *ids, struct pci_dev *dev);

int pci_scan_bridge(struct pci_bus *bus, struct pci_dev * dev, int max, int pass);



void pci_walk_bus(struct pci_bus *top, void (*cb)(struct pci_dev *, void *),

		  void *userdata);



/* kmem_cache style wrapper around pci_alloc_consistent() */



#include <linux/dmapool.h>

CRA Git | Maintained and supported by SUSTech CRA and CCSE