Revision 475049809977bf3975d78f2d2fd992e19ce2d59e authored by Roel Kluin on 10 March 2009, 19:55:45 UTC, committed by Linus Torvalds on 10 March 2009, 22:55:10 UTC
get_nid_for_pfn() returns int Presumably the (nid < 0) case has never happened. We do know that it is happening on one system while creating a symlink for a memory section so it should also happen on the same system if unregister_mem_sect_under_nodes() were called to remove the same symlink. The test was actually added in response to a problem with an earlier version reported by Yasunori Goto where one or more of the leading pages of a memory section on the 2nd node of one of his systems was uninitialized because I believe they coincided with a memory hole. That earlier version did not ignore uninitialized pages and determined the nid by considering only the 1st page of each memory section. This caused the symlink to the 1st memory section on the 2nd node to be incorrectly created in /sys/devices/system/node/node0 instead of /sys/devices/system/node/node1. The problem was fixed by adding the test to skip over uninitialized pages. I suspect we have not seen any reports of the non-removal of a symlink due to the incorrect declaration of the nid variable in unregister_mem_sect_under_nodes() because - systems where a memory section could have an uninitialized range of leading pages are probably rare. - memory remove is probably not done very frequently on the systems that are capable of demonstrating the problem. - lingering symlink(s) that should have been removed may have simply gone unnoticed. [garyhade@us.ibm.com: wrote changelog] Signed-off-by: Roel Kluin <roel.kluin@gmail.com> Cc: Gary Hade <garyhade@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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umc-bus.c
/*
* Bus for UWB Multi-interface Controller capabilities.
*
* Copyright (C) 2007 Cambridge Silicon Radio Ltd.
*
* This file is released under the GNU GPL v2.
*/
#include <linux/kernel.h>
#include <linux/sysfs.h>
#include <linux/workqueue.h>
#include <linux/uwb/umc.h>
#include <linux/pci.h>
static int umc_bus_pre_reset_helper(struct device *dev, void *data)
{
int ret = 0;
if (dev->driver) {
struct umc_dev *umc = to_umc_dev(dev);
struct umc_driver *umc_drv = to_umc_driver(dev->driver);
if (umc_drv->pre_reset)
ret = umc_drv->pre_reset(umc);
else
device_release_driver(dev);
}
return ret;
}
static int umc_bus_post_reset_helper(struct device *dev, void *data)
{
int ret = 0;
if (dev->driver) {
struct umc_dev *umc = to_umc_dev(dev);
struct umc_driver *umc_drv = to_umc_driver(dev->driver);
if (umc_drv->post_reset)
ret = umc_drv->post_reset(umc);
} else
ret = device_attach(dev);
return ret;
}
/**
* umc_controller_reset - reset the whole UMC controller
* @umc: the UMC device for the radio controller.
*
* Drivers or all capabilities of the controller will have their
* pre_reset methods called or be unbound from their device. Then all
* post_reset methods will be called or the drivers will be rebound.
*
* Radio controllers must provide pre_reset and post_reset methods and
* reset the hardware in their start method.
*
* If this is called while a probe() or remove() is in progress it
* will return -EAGAIN and not perform the reset.
*/
int umc_controller_reset(struct umc_dev *umc)
{
struct device *parent = umc->dev.parent;
int ret = 0;
if(down_trylock(&parent->sem))
return -EAGAIN;
ret = device_for_each_child(parent, parent, umc_bus_pre_reset_helper);
if (ret >= 0)
device_for_each_child(parent, parent, umc_bus_post_reset_helper);
up(&parent->sem);
return ret;
}
EXPORT_SYMBOL_GPL(umc_controller_reset);
/**
* umc_match_pci_id - match a UMC driver to a UMC device's parent PCI device.
* @umc_drv: umc driver with match_data pointing to a zero-terminated
* table of pci_device_id's.
* @umc: umc device whose parent is to be matched.
*/
int umc_match_pci_id(struct umc_driver *umc_drv, struct umc_dev *umc)
{
const struct pci_device_id *id_table = umc_drv->match_data;
struct pci_dev *pci;
if (umc->dev.parent->bus != &pci_bus_type)
return 0;
pci = to_pci_dev(umc->dev.parent);
return pci_match_id(id_table, pci) != NULL;
}
EXPORT_SYMBOL_GPL(umc_match_pci_id);
static int umc_bus_rescan_helper(struct device *dev, void *data)
{
int ret = 0;
if (!dev->driver)
ret = device_attach(dev);
return ret;
}
static void umc_bus_rescan(struct device *parent)
{
int err;
/*
* We can't use bus_rescan_devices() here as it deadlocks when
* it tries to retake the dev->parent semaphore.
*/
err = device_for_each_child(parent, NULL, umc_bus_rescan_helper);
if (err < 0)
printk(KERN_WARNING "%s: rescan of bus failed: %d\n",
KBUILD_MODNAME, err);
}
static int umc_bus_match(struct device *dev, struct device_driver *drv)
{
struct umc_dev *umc = to_umc_dev(dev);
struct umc_driver *umc_driver = to_umc_driver(drv);
if (umc->cap_id == umc_driver->cap_id) {
if (umc_driver->match)
return umc_driver->match(umc_driver, umc);
else
return 1;
}
return 0;
}
static int umc_device_probe(struct device *dev)
{
struct umc_dev *umc;
struct umc_driver *umc_driver;
int err;
umc_driver = to_umc_driver(dev->driver);
umc = to_umc_dev(dev);
get_device(dev);
err = umc_driver->probe(umc);
if (err)
put_device(dev);
else
umc_bus_rescan(dev->parent);
return err;
}
static int umc_device_remove(struct device *dev)
{
struct umc_dev *umc;
struct umc_driver *umc_driver;
umc_driver = to_umc_driver(dev->driver);
umc = to_umc_dev(dev);
umc_driver->remove(umc);
put_device(dev);
return 0;
}
static int umc_device_suspend(struct device *dev, pm_message_t state)
{
struct umc_dev *umc;
struct umc_driver *umc_driver;
int err = 0;
umc = to_umc_dev(dev);
if (dev->driver) {
umc_driver = to_umc_driver(dev->driver);
if (umc_driver->suspend)
err = umc_driver->suspend(umc, state);
}
return err;
}
static int umc_device_resume(struct device *dev)
{
struct umc_dev *umc;
struct umc_driver *umc_driver;
int err = 0;
umc = to_umc_dev(dev);
if (dev->driver) {
umc_driver = to_umc_driver(dev->driver);
if (umc_driver->resume)
err = umc_driver->resume(umc);
}
return err;
}
static ssize_t capability_id_show(struct device *dev, struct device_attribute *attr, char *buf)
{
struct umc_dev *umc = to_umc_dev(dev);
return sprintf(buf, "0x%02x\n", umc->cap_id);
}
static ssize_t version_show(struct device *dev, struct device_attribute *attr, char *buf)
{
struct umc_dev *umc = to_umc_dev(dev);
return sprintf(buf, "0x%04x\n", umc->version);
}
static struct device_attribute umc_dev_attrs[] = {
__ATTR_RO(capability_id),
__ATTR_RO(version),
__ATTR_NULL,
};
struct bus_type umc_bus_type = {
.name = "umc",
.match = umc_bus_match,
.probe = umc_device_probe,
.remove = umc_device_remove,
.suspend = umc_device_suspend,
.resume = umc_device_resume,
.dev_attrs = umc_dev_attrs,
};
EXPORT_SYMBOL_GPL(umc_bus_type);
static int __init umc_bus_init(void)
{
return bus_register(&umc_bus_type);
}
module_init(umc_bus_init);
static void __exit umc_bus_exit(void)
{
bus_unregister(&umc_bus_type);
}
module_exit(umc_bus_exit);
MODULE_DESCRIPTION("UWB Multi-interface Controller capability bus");
MODULE_AUTHOR("Cambridge Silicon Radio Ltd.");
MODULE_LICENSE("GPL");
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