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PCI: add remove_id sysfs entry 

This adds a remove_id sysfs entry to allow users of new_id to later
remove the added dynid.  One use case is management tools that want to
dynamically bind/unbind devices to pci-stub driver while devices are
assigned to KVM guests.  Rather than having to track which driver was
originally bound to the driver, a mangement tool can simply:

Guest uses device

Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
This commit is contained in:
Chris Wright 2009-02-23 21:52:23 -08:00 committed by Jesse Barnes
parent 13bf757669
commit 0994375e96
2 changed files with 94 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

16
Documentation/ABI/testing/sysfs-bus-pci
View File

@ -41,6 +41,22 @@ Description:
for the device and attempt to bind to it. For example:
# echo "8086 10f5" > /sys/bus/pci/drivers/foo/new_id
What: /sys/bus/pci/drivers/.../remove_id
Date: February 2009
Contact: Chris Wright <chrisw@sous-sol.org>
Description:
Writing a device ID to this file will remove an ID
that was dynamically added via the new_id sysfs entry.
The format for the device ID is:
VVVV DDDD SVVV SDDD CCCC MMMM. That is Vendor ID, Device
ID, Subsystem Vendor ID, Subsystem Device ID, Class,
and Class Mask. The Vendor ID and Device ID fields are
required, the rest are optional. After successfully
removing an ID, the driver will no longer support the
device. This is useful to ensure auto probing won't
match the driver to the device. For example:
# echo "8086 10f5" > /sys/bus/pci/drivers/foo/remove_id
What: /sys/bus/pci/devices/.../vpd
Date: February 2008
Contact: Ben Hutchings <bhutchings@solarflare.com>

80
drivers/pci/pci-driver.c
View File

@ -99,6 +99,52 @@ store_new_id(struct device_driver *driver, const char *buf, size_t count)
}
static DRIVER_ATTR(new_id, S_IWUSR, NULL, store_new_id);
/**
* store_remove_id - remove a PCI device ID from this driver
* @driver: target device driver
* @buf: buffer for scanning device ID data
* @count: input size
*
* Removes a dynamic pci device ID to this driver.
*/
static ssize_t
store_remove_id(struct device_driver *driver, const char *buf, size_t count)
{
struct pci_dynid *dynid, *n;
struct pci_driver *pdrv = to_pci_driver(driver);
__u32 vendor, device, subvendor = PCI_ANY_ID,
subdevice = PCI_ANY_ID, class = 0, class_mask = 0;
int fields = 0;
int retval = -ENODEV;
fields = sscanf(buf, "%x %x %x %x %x %x",
&vendor, &device, &subvendor, &subdevice,
&class, &class_mask);
if (fields < 2)
return -EINVAL;
spin_lock(&pdrv->dynids.lock);
list_for_each_entry_safe(dynid, n, &pdrv->dynids.list, node) {
struct pci_device_id *id = &dynid->id;
if ((id->vendor == vendor) &&
(id->device == device) &&
(subvendor == PCI_ANY_ID || id->subvendor == subvendor) &&
(subdevice == PCI_ANY_ID || id->subdevice == subdevice) &&
!((id->class ^ class) & class_mask)) {
list_del(&dynid->node);
kfree(dynid);
retval = 0;
break;
}
}
spin_unlock(&pdrv->dynids.lock);
if (retval)
return retval;
return count;
}
static DRIVER_ATTR(remove_id, S_IWUSR, NULL, store_remove_id);
static void
pci_free_dynids(struct pci_driver *drv)
{
@ -125,6 +171,20 @@ static void pci_remove_newid_file(struct pci_driver *drv)
{
driver_remove_file(&drv->driver, &driver_attr_new_id);
}
static int
pci_create_removeid_file(struct pci_driver *drv)
{
int error = 0;
if (drv->probe != NULL)
error = driver_create_file(&drv->driver,&driver_attr_remove_id);
return error;
}
static void pci_remove_removeid_file(struct pci_driver *drv)
{
driver_remove_file(&drv->driver, &driver_attr_remove_id);
}
#else /* !CONFIG_HOTPLUG */
static inline void pci_free_dynids(struct pci_driver *drv) {}
static inline int pci_create_newid_file(struct pci_driver *drv)
@ -132,6 +192,11 @@ static inline int pci_create_newid_file(struct pci_driver *drv)
return 0;
}
static inline void pci_remove_newid_file(struct pci_driver *drv) {}
static inline int pci_create_removeid_file(struct pci_driver *drv)
{
return 0;
}
static inline void pci_remove_removeid_file(struct pci_driver *drv) {}
#endif
/**
@ -852,13 +917,23 @@ int __pci_register_driver(struct pci_driver *drv, struct module *owner,
/* register with core */
error = driver_register(&drv->driver);
if (error)
return error;
goto out;
error = pci_create_newid_file(drv);
if (error)
driver_unregister(&drv->driver);
goto out_newid;
error = pci_create_removeid_file(drv);
if (error)
goto out_removeid;
out:
return error;
out_removeid:
pci_remove_newid_file(drv);
out_newid:
driver_unregister(&drv->driver);
goto out;
}
/**
@ -874,6 +949,7 @@ int __pci_register_driver(struct pci_driver *drv, struct module *owner,
void
pci_unregister_driver(struct pci_driver *drv)
{
pci_remove_removeid_file(drv);
pci_remove_newid_file(drv);
driver_unregister(&drv->driver);
pci_free_dynids(drv);