On Monday, October 28, 2019 11:00:23 PM CET Saravana Kannan wrote:
> Before this change, if a device is waiting on suppliers, it's assumed
> that all those suppliers are needed for the device to probe
> successfully. This change allows marking a devices as waiting only on
> optional suppliers. This allows a device to wait on suppliers (and link
> to them as soon as they are available) without preventing the device
> from being probed.
>
> Signed-off-by: Saravana Kannan <saravanak@xxxxxxxxxx>
> ---
> drivers/base/core.c | 28 +++++++++++++++++++++++++---
> include/linux/device.h | 3 +++
> 2 files changed, 28 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/base/core.c b/drivers/base/core.c
> index 17ed054c4132..48cd43a91ce6 100644
> --- a/drivers/base/core.c
> +++ b/drivers/base/core.c
> @@ -480,13 +480,25 @@ EXPORT_SYMBOL_GPL(device_link_add);
> * This function is NOT meant to be called from the probe function of the
> * consumer but rather from code that creates/adds the consumer device.
> */
> -static void device_link_wait_for_supplier(struct device *consumer)
> +static void device_link_wait_for_supplier(struct device *consumer,
> + bool need_for_probe)
> {
> mutex_lock(&wfs_lock);
> list_add_tail(&consumer->links.needs_suppliers, &wait_for_suppliers);
> + consumer->links.need_for_probe = need_for_probe;
> mutex_unlock(&wfs_lock);
> }
>
> +static void device_link_wait_for_mandatory_supplier(struct device *consumer)
> +{
> + device_link_wait_for_supplier(consumer, true);
> +}
> +
> +static void device_link_wait_for_optional_supplier(struct device *consumer)
> +{
> + device_link_wait_for_supplier(consumer, false);
> +}
> +
> /**
> * device_link_add_missing_supplier_links - Add links from consumer devices to
> * supplier devices, leaving any
> @@ -656,7 +668,8 @@ int device_links_check_suppliers(struct device *dev)
> * probe.
> */
> mutex_lock(&wfs_lock);
> - if (!list_empty(&dev->links.needs_suppliers)) {
> + if (!list_empty(&dev->links.needs_suppliers) &&
> + dev->links.need_for_probe) {
> mutex_unlock(&wfs_lock);
> return -EPROBE_DEFER;
> }
> @@ -760,6 +773,15 @@ void device_links_driver_bound(struct device *dev)
> {
> struct device_link *link;
>
> + /*
> + * If a device probes successfully, it's expected to have created all
> + * the device links it needs to or make new device links as it needs
> + * them. So, it no longer needs to wait on any suppliers.
> + */
> + mutex_lock(&wfs_lock);
> + list_del_init(&dev->links.needs_suppliers);
> + mutex_unlock(&wfs_lock);
> +
> device_links_write_lock();
>
> list_for_each_entry(link, &dev->links.consumers, s_node) {
> @@ -2393,7 +2415,7 @@ int device_add(struct device *dev)
>
> if (fwnode_has_op(dev->fwnode, add_links)
> && fwnode_call_int_op(dev->fwnode, add_links, dev))
> - device_link_wait_for_supplier(dev);
> + device_link_wait_for_mandatory_supplier(dev, true);
Does this compile even?
The function takes one argument according to the definition above ...
> bus_probe_device(dev);
> if (parent)
> diff --git a/include/linux/device.h b/include/linux/device.h
> index f1f2aa0b19da..4fd33da9a848 100644
> --- a/include/linux/device.h
> +++ b/include/linux/device.h
> @@ -1156,6 +1156,8 @@ enum dl_dev_state {
> * @consumers: List of links to consumer devices.
> * @needs_suppliers: Hook to global list of devices waiting for suppliers.
> * @defer_sync: Hook to global list of devices that have deferred sync_state.
> + * @need_for_probe: If needs_suppliers is on a list, this indicates if the
> + * suppliers are needed for probe or not.
> * @status: Driver status information.
> */
> struct dev_links_info {
> @@ -1163,6 +1165,7 @@ struct dev_links_info {
> struct list_head consumers;
> struct list_head needs_suppliers;
> struct list_head defer_sync;
> + bool need_for_probe;
> enum dl_dev_state status;
> };
>
>
