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linux-next/drivers/media/v4l2-core/v4l2-async.c
Niklas Söderlund 1453ad81a2 media: v4l: async: fix unregister for implicitly registered sub-device notifiers
The commit aef69d5475 ("media: v4l: fwnode: Add a convenience
function for registering sensors") adds the function
v4l2_async_notifier_parse_fwnode_sensor_common() to parse and register a
subdevice and a subdev-notifier by parsing firmware information. This
new subdev-notifier is stored in the new field 'subdev_notifier' in
struct v4l2_subdev.

In v4l2_async_unregister_subdev() this field is used to unregister and
cleanup the subdev-notifier. A check for if the subdev-notifier is
initialized or not was forgotten leading to a NULL pointer dereference
in v4l2_async_notifier_cleanup() if a subdevice do not use the optional
convince function to initialize the field.

Fix this by checking in v4l2_async_notifier_cleanup() that it is
provided whit a notifier making it safe to call with a NULL parameter.

Fixes: aef69d5475 ("media: v4l: fwnode: Add a convenience function for registering sensors")

Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-11-07 03:07:20 -05:00

622 lines
14 KiB
C

/*
* V4L2 asynchronous subdevice registration API
*
* Copyright (C) 2012-2013, Guennadi Liakhovetski <g.liakhovetski@gmx.de>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/device.h>
#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/list.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <media/v4l2-async.h>
#include <media/v4l2-device.h>
#include <media/v4l2-fwnode.h>
#include <media/v4l2-subdev.h>
static int v4l2_async_notifier_call_bound(struct v4l2_async_notifier *n,
struct v4l2_subdev *subdev,
struct v4l2_async_subdev *asd)
{
if (!n->ops || !n->ops->bound)
return 0;
return n->ops->bound(n, subdev, asd);
}
static void v4l2_async_notifier_call_unbind(struct v4l2_async_notifier *n,
struct v4l2_subdev *subdev,
struct v4l2_async_subdev *asd)
{
if (!n->ops || !n->ops->unbind)
return;
n->ops->unbind(n, subdev, asd);
}
static int v4l2_async_notifier_call_complete(struct v4l2_async_notifier *n)
{
if (!n->ops || !n->ops->complete)
return 0;
return n->ops->complete(n);
}
static bool match_i2c(struct v4l2_subdev *sd, struct v4l2_async_subdev *asd)
{
#if IS_ENABLED(CONFIG_I2C)
struct i2c_client *client = i2c_verify_client(sd->dev);
return client &&
asd->match.i2c.adapter_id == client->adapter->nr &&
asd->match.i2c.address == client->addr;
#else
return false;
#endif
}
static bool match_devname(struct v4l2_subdev *sd,
struct v4l2_async_subdev *asd)
{
return !strcmp(asd->match.device_name.name, dev_name(sd->dev));
}
static bool match_fwnode(struct v4l2_subdev *sd, struct v4l2_async_subdev *asd)
{
return sd->fwnode == asd->match.fwnode.fwnode;
}
static bool match_custom(struct v4l2_subdev *sd, struct v4l2_async_subdev *asd)
{
if (!asd->match.custom.match)
/* Match always */
return true;
return asd->match.custom.match(sd->dev, asd);
}
static LIST_HEAD(subdev_list);
static LIST_HEAD(notifier_list);
static DEFINE_MUTEX(list_lock);
static struct v4l2_async_subdev *v4l2_async_find_match(
struct v4l2_async_notifier *notifier, struct v4l2_subdev *sd)
{
bool (*match)(struct v4l2_subdev *, struct v4l2_async_subdev *);
struct v4l2_async_subdev *asd;
list_for_each_entry(asd, &notifier->waiting, list) {
/* bus_type has been verified valid before */
switch (asd->match_type) {
case V4L2_ASYNC_MATCH_CUSTOM:
match = match_custom;
break;
case V4L2_ASYNC_MATCH_DEVNAME:
match = match_devname;
break;
case V4L2_ASYNC_MATCH_I2C:
match = match_i2c;
break;
case V4L2_ASYNC_MATCH_FWNODE:
match = match_fwnode;
break;
default:
/* Cannot happen, unless someone breaks us */
WARN_ON(true);
return NULL;
}
/* match cannot be NULL here */
if (match(sd, asd))
return asd;
}
return NULL;
}
/* Find the sub-device notifier registered by a sub-device driver. */
static struct v4l2_async_notifier *v4l2_async_find_subdev_notifier(
struct v4l2_subdev *sd)
{
struct v4l2_async_notifier *n;
list_for_each_entry(n, &notifier_list, list)
if (n->sd == sd)
return n;
return NULL;
}
/* Get v4l2_device related to the notifier if one can be found. */
static struct v4l2_device *v4l2_async_notifier_find_v4l2_dev(
struct v4l2_async_notifier *notifier)
{
while (notifier->parent)
notifier = notifier->parent;
return notifier->v4l2_dev;
}
/*
* Return true if all child sub-device notifiers are complete, false otherwise.
*/
static bool v4l2_async_notifier_can_complete(
struct v4l2_async_notifier *notifier)
{
struct v4l2_subdev *sd;
if (!list_empty(&notifier->waiting))
return false;
list_for_each_entry(sd, &notifier->done, async_list) {
struct v4l2_async_notifier *subdev_notifier =
v4l2_async_find_subdev_notifier(sd);
if (subdev_notifier &&
!v4l2_async_notifier_can_complete(subdev_notifier))
return false;
}
return true;
}
/*
* Complete the master notifier if possible. This is done when all async
* sub-devices have been bound; v4l2_device is also available then.
*/
static int v4l2_async_notifier_try_complete(
struct v4l2_async_notifier *notifier)
{
/* Quick check whether there are still more sub-devices here. */
if (!list_empty(&notifier->waiting))
return 0;
/* Check the entire notifier tree; find the root notifier first. */
while (notifier->parent)
notifier = notifier->parent;
/* This is root if it has v4l2_dev. */
if (!notifier->v4l2_dev)
return 0;
/* Is everything ready? */
if (!v4l2_async_notifier_can_complete(notifier))
return 0;
return v4l2_async_notifier_call_complete(notifier);
}
static int v4l2_async_notifier_try_all_subdevs(
struct v4l2_async_notifier *notifier);
static int v4l2_async_match_notify(struct v4l2_async_notifier *notifier,
struct v4l2_device *v4l2_dev,
struct v4l2_subdev *sd,
struct v4l2_async_subdev *asd)
{
struct v4l2_async_notifier *subdev_notifier;
int ret;
ret = v4l2_device_register_subdev(v4l2_dev, sd);
if (ret < 0)
return ret;
ret = v4l2_async_notifier_call_bound(notifier, sd, asd);
if (ret < 0) {
v4l2_device_unregister_subdev(sd);
return ret;
}
/* Remove from the waiting list */
list_del(&asd->list);
sd->asd = asd;
sd->notifier = notifier;
/* Move from the global subdevice list to notifier's done */
list_move(&sd->async_list, &notifier->done);
/*
* See if the sub-device has a notifier. If not, return here.
*/
subdev_notifier = v4l2_async_find_subdev_notifier(sd);
if (!subdev_notifier || subdev_notifier->parent)
return 0;
/*
* Proceed with checking for the sub-device notifier's async
* sub-devices, and return the result. The error will be handled by the
* caller.
*/
subdev_notifier->parent = notifier;
return v4l2_async_notifier_try_all_subdevs(subdev_notifier);
}
/* Test all async sub-devices in a notifier for a match. */
static int v4l2_async_notifier_try_all_subdevs(
struct v4l2_async_notifier *notifier)
{
struct v4l2_device *v4l2_dev =
v4l2_async_notifier_find_v4l2_dev(notifier);
struct v4l2_subdev *sd;
if (!v4l2_dev)
return 0;
again:
list_for_each_entry(sd, &subdev_list, async_list) {
struct v4l2_async_subdev *asd;
int ret;
asd = v4l2_async_find_match(notifier, sd);
if (!asd)
continue;
ret = v4l2_async_match_notify(notifier, v4l2_dev, sd, asd);
if (ret < 0)
return ret;
/*
* v4l2_async_match_notify() may lead to registering a
* new notifier and thus changing the async subdevs
* list. In order to proceed safely from here, restart
* parsing the list from the beginning.
*/
goto again;
}
return 0;
}
static void v4l2_async_cleanup(struct v4l2_subdev *sd)
{
v4l2_device_unregister_subdev(sd);
/* Subdevice driver will reprobe and put the subdev back onto the list */
list_del_init(&sd->async_list);
sd->asd = NULL;
}
/* Unbind all sub-devices in the notifier tree. */
static void v4l2_async_notifier_unbind_all_subdevs(
struct v4l2_async_notifier *notifier)
{
struct v4l2_subdev *sd, *tmp;
list_for_each_entry_safe(sd, tmp, &notifier->done, async_list) {
struct v4l2_async_notifier *subdev_notifier =
v4l2_async_find_subdev_notifier(sd);
if (subdev_notifier)
v4l2_async_notifier_unbind_all_subdevs(subdev_notifier);
v4l2_async_notifier_call_unbind(notifier, sd, sd->asd);
v4l2_async_cleanup(sd);
list_move(&sd->async_list, &subdev_list);
}
notifier->parent = NULL;
}
/* See if an fwnode can be found in a notifier's lists. */
static bool __v4l2_async_notifier_fwnode_has_async_subdev(
struct v4l2_async_notifier *notifier, struct fwnode_handle *fwnode)
{
struct v4l2_async_subdev *asd;
struct v4l2_subdev *sd;
list_for_each_entry(asd, &notifier->waiting, list) {
if (asd->match_type != V4L2_ASYNC_MATCH_FWNODE)
continue;
if (asd->match.fwnode.fwnode == fwnode)
return true;
}
list_for_each_entry(sd, &notifier->done, async_list) {
if (WARN_ON(!sd->asd))
continue;
if (sd->asd->match_type != V4L2_ASYNC_MATCH_FWNODE)
continue;
if (sd->asd->match.fwnode.fwnode == fwnode)
return true;
}
return false;
}
/*
* Find out whether an async sub-device was set up for an fwnode already or
* whether it exists in a given notifier before @this_index.
*/
static bool v4l2_async_notifier_fwnode_has_async_subdev(
struct v4l2_async_notifier *notifier, struct fwnode_handle *fwnode,
unsigned int this_index)
{
unsigned int j;
lockdep_assert_held(&list_lock);
/* Check that an fwnode is not being added more than once. */
for (j = 0; j < this_index; j++) {
struct v4l2_async_subdev *asd = notifier->subdevs[this_index];
struct v4l2_async_subdev *other_asd = notifier->subdevs[j];
if (other_asd->match_type == V4L2_ASYNC_MATCH_FWNODE &&
asd->match.fwnode.fwnode ==
other_asd->match.fwnode.fwnode)
return true;
}
/* Check than an fwnode did not exist in other notifiers. */
list_for_each_entry(notifier, &notifier_list, list)
if (__v4l2_async_notifier_fwnode_has_async_subdev(
notifier, fwnode))
return true;
return false;
}
static int __v4l2_async_notifier_register(struct v4l2_async_notifier *notifier)
{
struct device *dev =
notifier->v4l2_dev ? notifier->v4l2_dev->dev : NULL;
struct v4l2_async_subdev *asd;
int ret;
int i;
if (notifier->num_subdevs > V4L2_MAX_SUBDEVS)
return -EINVAL;
INIT_LIST_HEAD(&notifier->waiting);
INIT_LIST_HEAD(&notifier->done);
mutex_lock(&list_lock);
for (i = 0; i < notifier->num_subdevs; i++) {
asd = notifier->subdevs[i];
switch (asd->match_type) {
case V4L2_ASYNC_MATCH_CUSTOM:
case V4L2_ASYNC_MATCH_DEVNAME:
case V4L2_ASYNC_MATCH_I2C:
break;
case V4L2_ASYNC_MATCH_FWNODE:
if (v4l2_async_notifier_fwnode_has_async_subdev(
notifier, asd->match.fwnode.fwnode, i)) {
dev_err(dev,
"fwnode has already been registered or in notifier's subdev list\n");
ret = -EEXIST;
goto err_unlock;
}
break;
default:
dev_err(dev, "Invalid match type %u on %p\n",
asd->match_type, asd);
ret = -EINVAL;
goto err_unlock;
}
list_add_tail(&asd->list, &notifier->waiting);
}
ret = v4l2_async_notifier_try_all_subdevs(notifier);
if (ret < 0)
goto err_unbind;
ret = v4l2_async_notifier_try_complete(notifier);
if (ret < 0)
goto err_unbind;
/* Keep also completed notifiers on the list */
list_add(&notifier->list, &notifier_list);
mutex_unlock(&list_lock);
return 0;
err_unbind:
/*
* On failure, unbind all sub-devices registered through this notifier.
*/
v4l2_async_notifier_unbind_all_subdevs(notifier);
err_unlock:
mutex_unlock(&list_lock);
return ret;
}
int v4l2_async_notifier_register(struct v4l2_device *v4l2_dev,
struct v4l2_async_notifier *notifier)
{
int ret;
if (WARN_ON(!v4l2_dev || notifier->sd))
return -EINVAL;
notifier->v4l2_dev = v4l2_dev;
ret = __v4l2_async_notifier_register(notifier);
if (ret)
notifier->v4l2_dev = NULL;
return ret;
}
EXPORT_SYMBOL(v4l2_async_notifier_register);
int v4l2_async_subdev_notifier_register(struct v4l2_subdev *sd,
struct v4l2_async_notifier *notifier)
{
int ret;
if (WARN_ON(!sd || notifier->v4l2_dev))
return -EINVAL;
notifier->sd = sd;
ret = __v4l2_async_notifier_register(notifier);
if (ret)
notifier->sd = NULL;
return ret;
}
EXPORT_SYMBOL(v4l2_async_subdev_notifier_register);
static void __v4l2_async_notifier_unregister(
struct v4l2_async_notifier *notifier)
{
if (!notifier || (!notifier->v4l2_dev && !notifier->sd))
return;
v4l2_async_notifier_unbind_all_subdevs(notifier);
notifier->sd = NULL;
notifier->v4l2_dev = NULL;
list_del(&notifier->list);
}
void v4l2_async_notifier_unregister(struct v4l2_async_notifier *notifier)
{
mutex_lock(&list_lock);
__v4l2_async_notifier_unregister(notifier);
mutex_unlock(&list_lock);
}
EXPORT_SYMBOL(v4l2_async_notifier_unregister);
void v4l2_async_notifier_cleanup(struct v4l2_async_notifier *notifier)
{
unsigned int i;
if (!notifier || !notifier->max_subdevs)
return;
for (i = 0; i < notifier->num_subdevs; i++) {
struct v4l2_async_subdev *asd = notifier->subdevs[i];
switch (asd->match_type) {
case V4L2_ASYNC_MATCH_FWNODE:
fwnode_handle_put(asd->match.fwnode.fwnode);
break;
default:
WARN_ON_ONCE(true);
break;
}
kfree(asd);
}
notifier->max_subdevs = 0;
notifier->num_subdevs = 0;
kvfree(notifier->subdevs);
notifier->subdevs = NULL;
}
EXPORT_SYMBOL_GPL(v4l2_async_notifier_cleanup);
int v4l2_async_register_subdev(struct v4l2_subdev *sd)
{
struct v4l2_async_notifier *subdev_notifier;
struct v4l2_async_notifier *notifier;
int ret;
/*
* No reference taken. The reference is held by the device
* (struct v4l2_subdev.dev), and async sub-device does not
* exist independently of the device at any point of time.
*/
if (!sd->fwnode && sd->dev)
sd->fwnode = dev_fwnode(sd->dev);
mutex_lock(&list_lock);
INIT_LIST_HEAD(&sd->async_list);
list_for_each_entry(notifier, &notifier_list, list) {
struct v4l2_device *v4l2_dev =
v4l2_async_notifier_find_v4l2_dev(notifier);
struct v4l2_async_subdev *asd;
if (!v4l2_dev)
continue;
asd = v4l2_async_find_match(notifier, sd);
if (!asd)
continue;
ret = v4l2_async_match_notify(notifier, notifier->v4l2_dev, sd,
asd);
if (ret)
goto err_unbind;
ret = v4l2_async_notifier_try_complete(notifier);
if (ret)
goto err_unbind;
goto out_unlock;
}
/* None matched, wait for hot-plugging */
list_add(&sd->async_list, &subdev_list);
out_unlock:
mutex_unlock(&list_lock);
return 0;
err_unbind:
/*
* Complete failed. Unbind the sub-devices bound through registering
* this async sub-device.
*/
subdev_notifier = v4l2_async_find_subdev_notifier(sd);
if (subdev_notifier)
v4l2_async_notifier_unbind_all_subdevs(subdev_notifier);
if (sd->asd)
v4l2_async_notifier_call_unbind(notifier, sd, sd->asd);
v4l2_async_cleanup(sd);
mutex_unlock(&list_lock);
return ret;
}
EXPORT_SYMBOL(v4l2_async_register_subdev);
void v4l2_async_unregister_subdev(struct v4l2_subdev *sd)
{
mutex_lock(&list_lock);
__v4l2_async_notifier_unregister(sd->subdev_notifier);
v4l2_async_notifier_cleanup(sd->subdev_notifier);
kfree(sd->subdev_notifier);
sd->subdev_notifier = NULL;
if (sd->asd) {
struct v4l2_async_notifier *notifier = sd->notifier;
list_add(&sd->asd->list, &notifier->waiting);
v4l2_async_notifier_call_unbind(notifier, sd, sd->asd);
}
v4l2_async_cleanup(sd);
mutex_unlock(&list_lock);
}
EXPORT_SYMBOL(v4l2_async_unregister_subdev);