linux/drivers/virtio/virtio.c
Suman Anna c13f99b7e9 virtio: fix memory leak of virtio ida cache layers
The virtio core uses a static ida named virtio_index_ida for
assigning index numbers to virtio devices during registration.
The ida core may allocate some internal idr cache layers and
an ida bitmap upon any ida allocation, and all these layers are
truely freed only upon the ida destruction. The virtio_index_ida
is not destroyed at present, leading to a memory leak when using
the virtio core as a module and atleast one virtio device is
registered and unregistered.

Fix this by invoking ida_destroy() in the virtio core module
exit.

Cc: stable@vger.kernel.org
Signed-off-by: Suman Anna <s-anna@ti.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2015-12-07 17:28:01 +02:00

421 lines
10 KiB
C

#include <linux/virtio.h>
#include <linux/spinlock.h>
#include <linux/virtio_config.h>
#include <linux/module.h>
#include <linux/idr.h>
#include <uapi/linux/virtio_ids.h>
/* Unique numbering for virtio devices. */
static DEFINE_IDA(virtio_index_ida);
static ssize_t device_show(struct device *_d,
struct device_attribute *attr, char *buf)
{
struct virtio_device *dev = dev_to_virtio(_d);
return sprintf(buf, "0x%04x\n", dev->id.device);
}
static DEVICE_ATTR_RO(device);
static ssize_t vendor_show(struct device *_d,
struct device_attribute *attr, char *buf)
{
struct virtio_device *dev = dev_to_virtio(_d);
return sprintf(buf, "0x%04x\n", dev->id.vendor);
}
static DEVICE_ATTR_RO(vendor);
static ssize_t status_show(struct device *_d,
struct device_attribute *attr, char *buf)
{
struct virtio_device *dev = dev_to_virtio(_d);
return sprintf(buf, "0x%08x\n", dev->config->get_status(dev));
}
static DEVICE_ATTR_RO(status);
static ssize_t modalias_show(struct device *_d,
struct device_attribute *attr, char *buf)
{
struct virtio_device *dev = dev_to_virtio(_d);
return sprintf(buf, "virtio:d%08Xv%08X\n",
dev->id.device, dev->id.vendor);
}
static DEVICE_ATTR_RO(modalias);
static ssize_t features_show(struct device *_d,
struct device_attribute *attr, char *buf)
{
struct virtio_device *dev = dev_to_virtio(_d);
unsigned int i;
ssize_t len = 0;
/* We actually represent this as a bitstring, as it could be
* arbitrary length in future. */
for (i = 0; i < sizeof(dev->features)*8; i++)
len += sprintf(buf+len, "%c",
__virtio_test_bit(dev, i) ? '1' : '0');
len += sprintf(buf+len, "\n");
return len;
}
static DEVICE_ATTR_RO(features);
static struct attribute *virtio_dev_attrs[] = {
&dev_attr_device.attr,
&dev_attr_vendor.attr,
&dev_attr_status.attr,
&dev_attr_modalias.attr,
&dev_attr_features.attr,
NULL,
};
ATTRIBUTE_GROUPS(virtio_dev);
static inline int virtio_id_match(const struct virtio_device *dev,
const struct virtio_device_id *id)
{
if (id->device != dev->id.device && id->device != VIRTIO_DEV_ANY_ID)
return 0;
return id->vendor == VIRTIO_DEV_ANY_ID || id->vendor == dev->id.vendor;
}
/* This looks through all the IDs a driver claims to support. If any of them
* match, we return 1 and the kernel will call virtio_dev_probe(). */
static int virtio_dev_match(struct device *_dv, struct device_driver *_dr)
{
unsigned int i;
struct virtio_device *dev = dev_to_virtio(_dv);
const struct virtio_device_id *ids;
ids = drv_to_virtio(_dr)->id_table;
for (i = 0; ids[i].device; i++)
if (virtio_id_match(dev, &ids[i]))
return 1;
return 0;
}
static int virtio_uevent(struct device *_dv, struct kobj_uevent_env *env)
{
struct virtio_device *dev = dev_to_virtio(_dv);
return add_uevent_var(env, "MODALIAS=virtio:d%08Xv%08X",
dev->id.device, dev->id.vendor);
}
static void add_status(struct virtio_device *dev, unsigned status)
{
dev->config->set_status(dev, dev->config->get_status(dev) | status);
}
void virtio_check_driver_offered_feature(const struct virtio_device *vdev,
unsigned int fbit)
{
unsigned int i;
struct virtio_driver *drv = drv_to_virtio(vdev->dev.driver);
for (i = 0; i < drv->feature_table_size; i++)
if (drv->feature_table[i] == fbit)
return;
if (drv->feature_table_legacy) {
for (i = 0; i < drv->feature_table_size_legacy; i++)
if (drv->feature_table_legacy[i] == fbit)
return;
}
BUG();
}
EXPORT_SYMBOL_GPL(virtio_check_driver_offered_feature);
static void __virtio_config_changed(struct virtio_device *dev)
{
struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
if (!dev->config_enabled)
dev->config_change_pending = true;
else if (drv && drv->config_changed)
drv->config_changed(dev);
}
void virtio_config_changed(struct virtio_device *dev)
{
unsigned long flags;
spin_lock_irqsave(&dev->config_lock, flags);
__virtio_config_changed(dev);
spin_unlock_irqrestore(&dev->config_lock, flags);
}
EXPORT_SYMBOL_GPL(virtio_config_changed);
static void virtio_config_disable(struct virtio_device *dev)
{
spin_lock_irq(&dev->config_lock);
dev->config_enabled = false;
spin_unlock_irq(&dev->config_lock);
}
static void virtio_config_enable(struct virtio_device *dev)
{
spin_lock_irq(&dev->config_lock);
dev->config_enabled = true;
if (dev->config_change_pending)
__virtio_config_changed(dev);
dev->config_change_pending = false;
spin_unlock_irq(&dev->config_lock);
}
static int virtio_finalize_features(struct virtio_device *dev)
{
int ret = dev->config->finalize_features(dev);
unsigned status;
if (ret)
return ret;
if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1))
return 0;
add_status(dev, VIRTIO_CONFIG_S_FEATURES_OK);
status = dev->config->get_status(dev);
if (!(status & VIRTIO_CONFIG_S_FEATURES_OK)) {
dev_err(&dev->dev, "virtio: device refuses features: %x\n",
status);
return -ENODEV;
}
return 0;
}
static int virtio_dev_probe(struct device *_d)
{
int err, i;
struct virtio_device *dev = dev_to_virtio(_d);
struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
u64 device_features;
u64 driver_features;
u64 driver_features_legacy;
/* We have a driver! */
add_status(dev, VIRTIO_CONFIG_S_DRIVER);
/* Figure out what features the device supports. */
device_features = dev->config->get_features(dev);
/* Figure out what features the driver supports. */
driver_features = 0;
for (i = 0; i < drv->feature_table_size; i++) {
unsigned int f = drv->feature_table[i];
BUG_ON(f >= 64);
driver_features |= (1ULL << f);
}
/* Some drivers have a separate feature table for virtio v1.0 */
if (drv->feature_table_legacy) {
driver_features_legacy = 0;
for (i = 0; i < drv->feature_table_size_legacy; i++) {
unsigned int f = drv->feature_table_legacy[i];
BUG_ON(f >= 64);
driver_features_legacy |= (1ULL << f);
}
} else {
driver_features_legacy = driver_features;
}
if (device_features & (1ULL << VIRTIO_F_VERSION_1))
dev->features = driver_features & device_features;
else
dev->features = driver_features_legacy & device_features;
/* Transport features always preserved to pass to finalize_features. */
for (i = VIRTIO_TRANSPORT_F_START; i < VIRTIO_TRANSPORT_F_END; i++)
if (device_features & (1ULL << i))
__virtio_set_bit(dev, i);
err = virtio_finalize_features(dev);
if (err)
goto err;
err = drv->probe(dev);
if (err)
goto err;
/* If probe didn't do it, mark device DRIVER_OK ourselves. */
if (!(dev->config->get_status(dev) & VIRTIO_CONFIG_S_DRIVER_OK))
virtio_device_ready(dev);
if (drv->scan)
drv->scan(dev);
virtio_config_enable(dev);
return 0;
err:
add_status(dev, VIRTIO_CONFIG_S_FAILED);
return err;
}
static int virtio_dev_remove(struct device *_d)
{
struct virtio_device *dev = dev_to_virtio(_d);
struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
virtio_config_disable(dev);
drv->remove(dev);
/* Driver should have reset device. */
WARN_ON_ONCE(dev->config->get_status(dev));
/* Acknowledge the device's existence again. */
add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
return 0;
}
static struct bus_type virtio_bus = {
.name = "virtio",
.match = virtio_dev_match,
.dev_groups = virtio_dev_groups,
.uevent = virtio_uevent,
.probe = virtio_dev_probe,
.remove = virtio_dev_remove,
};
int register_virtio_driver(struct virtio_driver *driver)
{
/* Catch this early. */
BUG_ON(driver->feature_table_size && !driver->feature_table);
driver->driver.bus = &virtio_bus;
return driver_register(&driver->driver);
}
EXPORT_SYMBOL_GPL(register_virtio_driver);
void unregister_virtio_driver(struct virtio_driver *driver)
{
driver_unregister(&driver->driver);
}
EXPORT_SYMBOL_GPL(unregister_virtio_driver);
int register_virtio_device(struct virtio_device *dev)
{
int err;
dev->dev.bus = &virtio_bus;
/* Assign a unique device index and hence name. */
err = ida_simple_get(&virtio_index_ida, 0, 0, GFP_KERNEL);
if (err < 0)
goto out;
dev->index = err;
dev_set_name(&dev->dev, "virtio%u", dev->index);
spin_lock_init(&dev->config_lock);
dev->config_enabled = false;
dev->config_change_pending = false;
/* We always start by resetting the device, in case a previous
* driver messed it up. This also tests that code path a little. */
dev->config->reset(dev);
/* Acknowledge that we've seen the device. */
add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
INIT_LIST_HEAD(&dev->vqs);
/* device_register() causes the bus infrastructure to look for a
* matching driver. */
err = device_register(&dev->dev);
out:
if (err)
add_status(dev, VIRTIO_CONFIG_S_FAILED);
return err;
}
EXPORT_SYMBOL_GPL(register_virtio_device);
void unregister_virtio_device(struct virtio_device *dev)
{
int index = dev->index; /* save for after device release */
device_unregister(&dev->dev);
ida_simple_remove(&virtio_index_ida, index);
}
EXPORT_SYMBOL_GPL(unregister_virtio_device);
#ifdef CONFIG_PM_SLEEP
int virtio_device_freeze(struct virtio_device *dev)
{
struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
virtio_config_disable(dev);
dev->failed = dev->config->get_status(dev) & VIRTIO_CONFIG_S_FAILED;
if (drv && drv->freeze)
return drv->freeze(dev);
return 0;
}
EXPORT_SYMBOL_GPL(virtio_device_freeze);
int virtio_device_restore(struct virtio_device *dev)
{
struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
int ret;
/* We always start by resetting the device, in case a previous
* driver messed it up. */
dev->config->reset(dev);
/* Acknowledge that we've seen the device. */
add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
/* Maybe driver failed before freeze.
* Restore the failed status, for debugging. */
if (dev->failed)
add_status(dev, VIRTIO_CONFIG_S_FAILED);
if (!drv)
return 0;
/* We have a driver! */
add_status(dev, VIRTIO_CONFIG_S_DRIVER);
ret = virtio_finalize_features(dev);
if (ret)
goto err;
if (drv->restore) {
ret = drv->restore(dev);
if (ret)
goto err;
}
/* Finally, tell the device we're all set */
add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK);
virtio_config_enable(dev);
return 0;
err:
add_status(dev, VIRTIO_CONFIG_S_FAILED);
return ret;
}
EXPORT_SYMBOL_GPL(virtio_device_restore);
#endif
static int virtio_init(void)
{
if (bus_register(&virtio_bus) != 0)
panic("virtio bus registration failed");
return 0;
}
static void __exit virtio_exit(void)
{
bus_unregister(&virtio_bus);
ida_destroy(&virtio_index_ida);
}
core_initcall(virtio_init);
module_exit(virtio_exit);
MODULE_LICENSE("GPL");