[PATCH v16 19/32] v4l: async: Ensure only unique fwnodes are registered to notifiers

Sakari Ailus
2017-10-26T07:53:29Z

While registering a notifier, check that each newly added fwnode is
unique, and return an error if it is not. Also check that a newly added
notifier does not have the same fwnodes twice.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
---
drivers/media/v4l2-core/v4l2-async.c | 82 +++++++++++++++++++++++++++++++++---
1 file changed, 77 insertions(+), 5 deletions(-)

diff --git a/drivers/media/v4l2-core/v4l2-async.c b/drivers/media/v4l2-core/v4l2-async.c
index ed539c4fd5dc..b4e88eef195f 100644
--- a/drivers/media/v4l2-core/v4l2-async.c
+++ b/drivers/media/v4l2-core/v4l2-async.c
@@ -308,8 +308,71 @@ static void v4l2_async_notifier_unbind_all_subdevs(
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;
@@ -320,6 +383,8 @@ static int __v4l2_async_notifier_register(struct v4l2_async_notifier *notifier)
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];

@@ -327,19 +392,25 @@ static int __v4l2_async_notifier_register(struct v4l2_async_notifier *notifier)
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 out_unlock;
+ }
break;
default:
- dev_err(notifier->v4l2_dev ? notifier->v4l2_dev->dev : NULL,
- "Invalid match type %u on %p\n",
+ dev_err(dev, "Invalid match type %u on %p\n",
asd->match_type, asd);
- return -EINVAL;
+ ret = -EINVAL;
+ goto out_unlock;
}
list_add_tail(&asd->list, &notifier->waiting);
}

- mutex_lock(&list_lock);
-
ret = v4l2_async_notifier_try_all_subdevs(notifier);
if (ret)
goto err_unbind;
@@ -351,6 +422,7 @@ static int __v4l2_async_notifier_register(struct v4l2_async_notifier *notifier)
/* Keep also completed notifiers on the list */
list_add(&notifier->list, &notifier_list);

+out_unlock:
mutex_unlock(&list_lock);

return 0;
--
2.11.0