media: v4l: async: Ensure only unique fwnodes are registered to notifiers

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>
Acked-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Reviewed-by: Sebastian Reichel <sebastian.reichel@collabora.co.uk>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

diff --git a/drivers/media/v4l2-core/v4l2-async.c b/drivers/media/v4l2-core/v4l2-async.c
index ed539c4..57bd540 100644 (file)
--- 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];
 
@@ -327,25 +392,31 @@ 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 err_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 err_unlock;
                }
                list_add_tail(&asd->list, &notifier->waiting);
        }
 
-       mutex_lock(&list_lock);
-
        ret = v4l2_async_notifier_try_all_subdevs(notifier);
-       if (ret)
+       if (ret < 0)
                goto err_unbind;
 
        ret = v4l2_async_notifier_try_complete(notifier);
-       if (ret)
+       if (ret < 0)
                goto err_unbind;
 
        /* Keep also completed notifiers on the list */
@@ -361,6 +432,7 @@ err_unbind:
         */
        v4l2_async_notifier_unbind_all_subdevs(notifier);
 
+err_unlock:
        mutex_unlock(&list_lock);
 
        return ret;