Hi Steve,
Thanks for the patchset.
On Tue, Mar 20, 2018 at 05:37:19PM -0700, Steve Longerbeam wrote:
> v4l2_async_notifier_add_subdev() adds an asd to the notifier. It checks
> that the asd's match_type is valid and that no other equivalent asd's
> have already been added to this notifier's asd list, or to other
> registered notifier's waiting or done lists, and increments num_subdevs.
>
> v4l2_async_notifier_add_subdev() does not make use of the notifier subdevs
> array, otherwise it would have to re-allocate the array every time the
> function was called. In place of the subdevs array, the function adds
> the asd to a new master asd_list. The function will return error with a
> WARN() if it is ever called with the subdevs array allocated.
>
> In v4l2_async_notifier_has_async_subdev(), __v4l2_async_notifier_register(),
> and v4l2_async_notifier_cleanup(), alternatively operate on the subdevs
> array or a non-empty notifier->asd_list.
I do agree with the approach, but this patch leaves the remaining users of
the subdevs array in the notifier intact. Could you rework them to use the
v4l2_async_notifier_add_subdev() as well?
There seem to be just a few of them --- exynos4-is and rcar_drif.
>
> Signed-off-by: Steve Longerbeam <steve_longerbeam@xxxxxxxxxx>
> ---
> Changes since v2:
> - add a NULL asd pointer check to v4l2_async_notifier_asd_valid().
> Changes since v1:
> - none
> ---
> drivers/media/v4l2-core/v4l2-async.c | 206 +++++++++++++++++++++++++++--------
> include/media/v4l2-async.h | 22 ++++
> 2 files changed, 184 insertions(+), 44 deletions(-)
>
> diff --git a/drivers/media/v4l2-core/v4l2-async.c b/drivers/media/v4l2-core/v4l2-async.c
> index b59bbac..7b7f7e2 100644
> --- a/drivers/media/v4l2-core/v4l2-async.c
> +++ b/drivers/media/v4l2-core/v4l2-async.c
> @@ -366,16 +366,26 @@ static bool v4l2_async_notifier_has_async_subdev(
> struct v4l2_async_notifier *notifier, struct v4l2_async_subdev *asd,
> unsigned int this_index)
> {
> + struct v4l2_async_subdev *asd_y;
> unsigned int j;
>
> lockdep_assert_held(&list_lock);
>
> /* Check that an asd is not being added more than once. */
> - for (j = 0; j < this_index; j++) {
> - struct v4l2_async_subdev *asd_y = notifier->subdevs[j];
> -
> - if (asd_equal(asd, asd_y))
> - return true;
> + if (notifier->subdevs) {
> + for (j = 0; j < this_index; j++) {
> + asd_y = notifier->subdevs[j];
> + if (asd_equal(asd, asd_y))
> + return true;
> + }
> + } else {
> + j = 0;
> + list_for_each_entry(asd_y, ¬ifier->asd_list, asd_list) {
> + if (j++ >= this_index)
> + break;
> + if (asd_equal(asd, asd_y))
> + return true;
> + }
> }
>
> /* Check that an asd does not exist in other notifiers. */
> @@ -386,10 +396,46 @@ static bool v4l2_async_notifier_has_async_subdev(
> return false;
> }
>
> -static int __v4l2_async_notifier_register(struct v4l2_async_notifier *notifier)
> +static int v4l2_async_notifier_asd_valid(struct v4l2_async_notifier *notifier,
> + struct v4l2_async_subdev *asd,
> + unsigned int this_index)
> {
> struct device *dev =
> notifier->v4l2_dev ? notifier->v4l2_dev->dev : NULL;
> +
> + if (!asd)
> + return -EINVAL;
> +
> + switch (asd->match_type) {
> + case V4L2_ASYNC_MATCH_CUSTOM:
> + case V4L2_ASYNC_MATCH_DEVNAME:
> + case V4L2_ASYNC_MATCH_I2C:
> + case V4L2_ASYNC_MATCH_FWNODE:
> + if (v4l2_async_notifier_has_async_subdev(notifier, asd,
> + this_index))
> + return -EEXIST;
> + break;
> + default:
> + dev_err(dev, "Invalid match type %u on %p\n",
> + asd->match_type, asd);
> + return -EINVAL;
> + }
> +
> + return 0;
> +}
> +
> +static void __v4l2_async_notifier_init(struct v4l2_async_notifier *notifier)
> +{
> + lockdep_assert_held(&list_lock);
> +
> + INIT_LIST_HEAD(¬ifier->asd_list);
> + INIT_LIST_HEAD(¬ifier->waiting);
> + INIT_LIST_HEAD(¬ifier->done);
> + notifier->lists_initialized = true;
> +}
> +
> +static int __v4l2_async_notifier_register(struct v4l2_async_notifier *notifier)
> +{
> struct v4l2_async_subdev *asd;
> int ret;
> int i;
> @@ -397,34 +443,40 @@ static int __v4l2_async_notifier_register(struct v4l2_async_notifier *notifier)
> if (notifier->num_subdevs > V4L2_MAX_SUBDEVS)
> return -EINVAL;
>
> - INIT_LIST_HEAD(¬ifier->waiting);
> - INIT_LIST_HEAD(¬ifier->done);
> -
> mutex_lock(&list_lock);
>
> - for (i = 0; i < notifier->num_subdevs; i++) {
> - asd = notifier->subdevs[i];
> + if (!notifier->lists_initialized)
> + __v4l2_async_notifier_init(notifier);
>
> - switch (asd->match_type) {
> - case V4L2_ASYNC_MATCH_CUSTOM:
> - case V4L2_ASYNC_MATCH_DEVNAME:
> - case V4L2_ASYNC_MATCH_I2C:
> - case V4L2_ASYNC_MATCH_FWNODE:
> - if (v4l2_async_notifier_has_async_subdev(
> - notifier, asd, i)) {
> - dev_err(dev,
> - "asd 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);
> + if (!list_empty(¬ifier->asd_list)) {
> + /*
> + * Caller must have either used v4l2_async_notifier_add_subdev
> + * to add asd's to notifier->asd_list, or provided the
> + * notifier->subdevs array, but not both.
> + */
> + if (WARN_ON(notifier->subdevs)) {
> ret = -EINVAL;
> goto err_unlock;
> }
> - list_add_tail(&asd->list, ¬ifier->waiting);
> +
> + i = 0;
> + list_for_each_entry(asd, ¬ifier->asd_list, asd_list) {
> + ret = v4l2_async_notifier_asd_valid(notifier, asd, i++);
> + if (ret)
> + goto err_unlock;
> +
> + list_add_tail(&asd->list, ¬ifier->waiting);
> + }
> + } else if (notifier->subdevs) {
> + for (i = 0; i < notifier->num_subdevs; i++) {
> + asd = notifier->subdevs[i];
> +
> + ret = v4l2_async_notifier_asd_valid(notifier, asd, i);
> + if (ret)
> + goto err_unlock;
> +
> + list_add_tail(&asd->list, ¬ifier->waiting);
> + }
> }
>
> ret = v4l2_async_notifier_try_all_subdevs(notifier);
> @@ -514,36 +566,102 @@ void v4l2_async_notifier_unregister(struct v4l2_async_notifier *notifier)
> }
> EXPORT_SYMBOL(v4l2_async_notifier_unregister);
>
> -void v4l2_async_notifier_cleanup(struct v4l2_async_notifier *notifier)
> +static void __v4l2_async_notifier_cleanup(struct v4l2_async_notifier *notifier)
> {
> + struct v4l2_async_subdev *asd, *tmp;
> unsigned int i;
>
> - if (!notifier || !notifier->max_subdevs)
> + if (!notifier)
> return;
>
> - for (i = 0; i < notifier->num_subdevs; i++) {
> - struct v4l2_async_subdev *asd = notifier->subdevs[i];
> + if (notifier->subdevs) {
> + if (!notifier->max_subdevs)
> + return;
>
> - switch (asd->match_type) {
> - case V4L2_ASYNC_MATCH_FWNODE:
> - fwnode_handle_put(asd->match.fwnode);
> - break;
> - default:
> - WARN_ON_ONCE(true);
> - break;
> + for (i = 0; i < notifier->num_subdevs; i++) {
> + asd = notifier->subdevs[i];
> +
> + switch (asd->match_type) {
> + case V4L2_ASYNC_MATCH_FWNODE:
> + fwnode_handle_put(asd->match.fwnode);
> + break;
> + default:
> + break;
> + }
> +
> + kfree(asd);
> }
>
> - kfree(asd);
> + notifier->max_subdevs = 0;
> + kvfree(notifier->subdevs);
> + notifier->subdevs = NULL;
> + } else if (notifier->lists_initialized) {
> + list_for_each_entry_safe(asd, tmp,
> + ¬ifier->asd_list, asd_list) {
> + switch (asd->match_type) {
> + case V4L2_ASYNC_MATCH_FWNODE:
> + fwnode_handle_put(asd->match.fwnode);
> + break;
> + default:
> + break;
> + }
> +
> + list_del(&asd->asd_list);
> + kfree(asd);
> + }
> }
>
> - notifier->max_subdevs = 0;
> notifier->num_subdevs = 0;
> +}
>
> - kvfree(notifier->subdevs);
> - notifier->subdevs = NULL;
> +void v4l2_async_notifier_cleanup(struct v4l2_async_notifier *notifier)
> +{
> + mutex_lock(&list_lock);
> +
> + __v4l2_async_notifier_cleanup(notifier);
> +
> + mutex_unlock(&list_lock);
> }
> EXPORT_SYMBOL_GPL(v4l2_async_notifier_cleanup);
>
> +int v4l2_async_notifier_add_subdev(struct v4l2_async_notifier *notifier,
> + struct v4l2_async_subdev *asd)
> +{
> + int ret = 0;
> +
> + mutex_lock(&list_lock);
> +
> + if (notifier->num_subdevs >= V4L2_MAX_SUBDEVS) {
> + ret = -EINVAL;
> + goto unlock;
> + }
> +
> + if (!notifier->lists_initialized)
> + __v4l2_async_notifier_init(notifier);
> +
> + /*
> + * If caller uses this function, it cannot also allocate and
> + * place asd's in the notifier->subdevs array.
> + */
> + if (WARN_ON(notifier->subdevs)) {
> + ret = -EINVAL;
> + goto unlock;
> + }
> +
> + ret = v4l2_async_notifier_asd_valid(notifier, asd,
> + notifier->num_subdevs);
> + if (ret)
> + goto unlock;
> +
> + list_add_tail(&asd->asd_list, ¬ifier->asd_list);
> + notifier->num_subdevs++;
> +
> +unlock:
> + mutex_unlock(&list_lock);
> + return ret;
> +}
> +EXPORT_SYMBOL_GPL(v4l2_async_notifier_add_subdev);
> +
> int v4l2_async_register_subdev(struct v4l2_subdev *sd)
> {
> struct v4l2_async_notifier *subdev_notifier;
> @@ -617,7 +735,7 @@ 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);
> + __v4l2_async_notifier_cleanup(sd->subdev_notifier);
> kfree(sd->subdev_notifier);
> sd->subdev_notifier = NULL;
>
> diff --git a/include/media/v4l2-async.h b/include/media/v4l2-async.h
> index 1592d32..fa05905 100644
> --- a/include/media/v4l2-async.h
> +++ b/include/media/v4l2-async.h
> @@ -73,6 +73,8 @@ enum v4l2_async_match_type {
> * @match.custom.priv:
> * Driver-specific private struct with match parameters
> * to be used if %V4L2_ASYNC_MATCH_CUSTOM.
> + * @asd_list: used to add struct v4l2_async_subdev objects to the
> + * master notifier->asd_list
> * @list: used to link struct v4l2_async_subdev objects, waiting to be
> * probed, to a notifier->waiting list
> *
> @@ -98,6 +100,7 @@ struct v4l2_async_subdev {
>
> /* v4l2-async core private: not to be used by drivers */
> struct list_head list;
> + struct list_head asd_list;
> };
>
> /**
> @@ -127,9 +130,11 @@ struct v4l2_async_notifier_operations {
> * @v4l2_dev: v4l2_device of the root notifier, NULL otherwise
> * @sd: sub-device that registered the notifier, NULL otherwise
> * @parent: parent notifier
> + * @asd_list: master list of struct v4l2_async_subdev, replaces @subdevs
> * @waiting: list of struct v4l2_async_subdev, waiting for their drivers
> * @done: list of struct v4l2_subdev, already probed
> * @list: member in a global list of notifiers
> + * @lists_initialized: list_head's have been initialized
> */
> struct v4l2_async_notifier {
> const struct v4l2_async_notifier_operations *ops;
> @@ -139,12 +144,29 @@ struct v4l2_async_notifier {
> struct v4l2_device *v4l2_dev;
> struct v4l2_subdev *sd;
> struct v4l2_async_notifier *parent;
> + struct list_head asd_list;
> struct list_head waiting;
> struct list_head done;
> struct list_head list;
> + bool lists_initialized;
> };
>
> /**
> + * v4l2_async_notifier_add_subdev - Add an async subdev to the
> + * notifier's master asd_list.
> + *
> + * @notifier: pointer to &struct v4l2_async_notifier
> + * @asd: pointer to &struct v4l2_async_subdev
> + *
> + * This can be used before registering a notifier to add an
> + * asd to the notifiers master asd_list. If the caller uses
> + * this method to compose an asd list, it must never allocate
> + * or place asd's in the @subdevs array.
> + */
> +int v4l2_async_notifier_add_subdev(struct v4l2_async_notifier *notifier,
> + struct v4l2_async_subdev *asd);
> +
> +/**
> * v4l2_async_notifier_register - registers a subdevice asynchronous notifier
> *
> * @v4l2_dev: pointer to &struct v4l2_device
> --
> 2.7.4
>
--
Sakari Ailus
sakari.ailus@xxxxxxxxxxxxxxx
