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vmbus: add support for dynamic device id's
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This patch adds sysfs interface to dynamically bind new UUID values
to existing VMBus device. This is useful for generic UIO driver to
act similar to uio_pci_generic.

Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Stephen Hemminger authored and Greg Kroah-Hartman committed Dec 6, 2016
1 parent 6ffc4b8 commit fc76936
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Showing 2 changed files with 172 additions and 8 deletions.
174 changes: 166 additions & 8 deletions drivers/hv/vmbus_drv.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -45,6 +45,11 @@
#include <linux/random.h>
#include "hyperv_vmbus.h"

struct vmbus_dynid {
struct list_head node;
struct hv_vmbus_device_id id;
};

static struct acpi_device *hv_acpi_dev;

static struct completion probe_event;
Expand Down Expand Up @@ -500,7 +505,7 @@ static ssize_t device_show(struct device *dev,
static DEVICE_ATTR_RO(device);

/* Set up per device attributes in /sys/bus/vmbus/devices/<bus device> */
static struct attribute *vmbus_attrs[] = {
static struct attribute *vmbus_dev_attrs[] = {
&dev_attr_id.attr,
&dev_attr_state.attr,
&dev_attr_monitor_id.attr,
Expand Down Expand Up @@ -528,7 +533,7 @@ static struct attribute *vmbus_attrs[] = {
&dev_attr_device.attr,
NULL,
};
ATTRIBUTE_GROUPS(vmbus);
ATTRIBUTE_GROUPS(vmbus_dev);

/*
* vmbus_uevent - add uevent for our device
Expand Down Expand Up @@ -565,17 +570,164 @@ static inline bool is_null_guid(const uuid_le *guid)
* Return a matching hv_vmbus_device_id pointer.
* If there is no match, return NULL.
*/
static const struct hv_vmbus_device_id *hv_vmbus_get_id(
const struct hv_vmbus_device_id *id,
static const struct hv_vmbus_device_id *hv_vmbus_get_id(struct hv_driver *drv,
const uuid_le *guid)
{
const struct hv_vmbus_device_id *id = NULL;
struct vmbus_dynid *dynid;

/* Look at the dynamic ids first, before the static ones */
spin_lock(&drv->dynids.lock);
list_for_each_entry(dynid, &drv->dynids.list, node) {
if (!uuid_le_cmp(dynid->id.guid, *guid)) {
id = &dynid->id;
break;
}
}
spin_unlock(&drv->dynids.lock);

if (id)
return id;

id = drv->id_table;
if (id == NULL)
return NULL; /* empty device table */

for (; !is_null_guid(&id->guid); id++)
if (!uuid_le_cmp(id->guid, *guid))
return id;

return NULL;
}

/* vmbus_add_dynid - add a new device ID to this driver and re-probe devices */
static int vmbus_add_dynid(struct hv_driver *drv, uuid_le *guid)
{
struct vmbus_dynid *dynid;

dynid = kzalloc(sizeof(*dynid), GFP_KERNEL);
if (!dynid)
return -ENOMEM;

dynid->id.guid = *guid;

spin_lock(&drv->dynids.lock);
list_add_tail(&dynid->node, &drv->dynids.list);
spin_unlock(&drv->dynids.lock);

return driver_attach(&drv->driver);
}

static void vmbus_free_dynids(struct hv_driver *drv)
{
struct vmbus_dynid *dynid, *n;

spin_lock(&drv->dynids.lock);
list_for_each_entry_safe(dynid, n, &drv->dynids.list, node) {
list_del(&dynid->node);
kfree(dynid);
}
spin_unlock(&drv->dynids.lock);
}

/* Parse string of form: 1b4e28ba-2fa1-11d2-883f-b9a761bde3f */
static int get_uuid_le(const char *str, uuid_le *uu)
{
unsigned int b[16];
int i;

if (strlen(str) < 37)
return -1;

for (i = 0; i < 36; i++) {
switch (i) {
case 8: case 13: case 18: case 23:
if (str[i] != '-')
return -1;
break;
default:
if (!isxdigit(str[i]))
return -1;
}
}

/* unparse little endian output byte order */
if (sscanf(str,
"%2x%2x%2x%2x-%2x%2x-%2x%2x-%2x%2x-%2x%2x%2x%2x%2x%2x",
&b[3], &b[2], &b[1], &b[0],
&b[5], &b[4], &b[7], &b[6], &b[8], &b[9],
&b[10], &b[11], &b[12], &b[13], &b[14], &b[15]) != 16)
return -1;

for (i = 0; i < 16; i++)
uu->b[i] = b[i];
return 0;
}

/*
* store_new_id - sysfs frontend to vmbus_add_dynid()
*
* Allow GUIDs to be added to an existing driver via sysfs.
*/
static ssize_t new_id_store(struct device_driver *driver, const char *buf,
size_t count)
{
struct hv_driver *drv = drv_to_hv_drv(driver);
uuid_le guid = NULL_UUID_LE;
ssize_t retval;

if (get_uuid_le(buf, &guid) != 0)
return -EINVAL;

if (hv_vmbus_get_id(drv, &guid))
return -EEXIST;

retval = vmbus_add_dynid(drv, &guid);
if (retval)
return retval;
return count;
}
static DRIVER_ATTR_WO(new_id);

/*
* store_remove_id - remove a PCI device ID from this driver
*
* Removes a dynamic pci device ID to this driver.
*/
static ssize_t remove_id_store(struct device_driver *driver, const char *buf,
size_t count)
{
struct hv_driver *drv = drv_to_hv_drv(driver);
struct vmbus_dynid *dynid, *n;
uuid_le guid = NULL_UUID_LE;
size_t retval = -ENODEV;

if (get_uuid_le(buf, &guid))
return -EINVAL;

spin_lock(&drv->dynids.lock);
list_for_each_entry_safe(dynid, n, &drv->dynids.list, node) {
struct hv_vmbus_device_id *id = &dynid->id;

if (!uuid_le_cmp(id->guid, guid)) {
list_del(&dynid->node);
kfree(dynid);
retval = count;
break;
}
}
spin_unlock(&drv->dynids.lock);

return retval;
}
static DRIVER_ATTR_WO(remove_id);

static struct attribute *vmbus_drv_attrs[] = {
&driver_attr_new_id.attr,
&driver_attr_remove_id.attr,
NULL,
};
ATTRIBUTE_GROUPS(vmbus_drv);


/*
Expand All @@ -590,7 +742,7 @@ static int vmbus_match(struct device *device, struct device_driver *driver)
if (is_hvsock_channel(hv_dev->channel))
return drv->hvsock;

if (hv_vmbus_get_id(drv->id_table, &hv_dev->dev_type))
if (hv_vmbus_get_id(drv, &hv_dev->dev_type))
return 1;

return 0;
Expand All @@ -607,7 +759,7 @@ static int vmbus_probe(struct device *child_device)
struct hv_device *dev = device_to_hv_device(child_device);
const struct hv_vmbus_device_id *dev_id;

dev_id = hv_vmbus_get_id(drv->id_table, &dev->dev_type);
dev_id = hv_vmbus_get_id(drv, &dev->dev_type);
if (drv->probe) {
ret = drv->probe(dev, dev_id);
if (ret != 0)
Expand Down Expand Up @@ -684,7 +836,8 @@ static struct bus_type hv_bus = {
.remove = vmbus_remove,
.probe = vmbus_probe,
.uevent = vmbus_uevent,
.dev_groups = vmbus_groups,
.dev_groups = vmbus_dev_groups,
.drv_groups = vmbus_drv_groups,
};

struct onmessage_work_context {
Expand Down Expand Up @@ -905,6 +1058,9 @@ int __vmbus_driver_register(struct hv_driver *hv_driver, struct module *owner, c
hv_driver->driver.mod_name = mod_name;
hv_driver->driver.bus = &hv_bus;

spin_lock_init(&hv_driver->dynids.lock);
INIT_LIST_HEAD(&hv_driver->dynids.list);

ret = driver_register(&hv_driver->driver);

return ret;
Expand All @@ -923,8 +1079,10 @@ void vmbus_driver_unregister(struct hv_driver *hv_driver)
{
pr_info("unregistering driver %s\n", hv_driver->name);

if (!vmbus_exists())
if (!vmbus_exists()) {
driver_unregister(&hv_driver->driver);
vmbus_free_dynids(hv_driver);
}
}
EXPORT_SYMBOL_GPL(vmbus_driver_unregister);

Expand Down
6 changes: 6 additions & 0 deletions include/linux/hyperv.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1119,6 +1119,12 @@ struct hv_driver {

struct device_driver driver;

/* dynamic device GUID's */
struct {
spinlock_t lock;
struct list_head list;
} dynids;

int (*probe)(struct hv_device *, const struct hv_vmbus_device_id *);
int (*remove)(struct hv_device *);
void (*shutdown)(struct hv_device *);
Expand Down

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