diff options
| author |   Saravana Kannan <saravanak@google.com> | 2019-10-28 15:00:23 -0700 |
|---|---|---|
| committer |   Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-11-02 18:05:17 +0100 |
| commit | bcbbcfd57247f4c2976055995e5760fb576aae1e (patch) | |
| tree | cb6db68c1ef8083ff8eb7899b2fd6d1a1dbce94c /drivers/base/core.c | |
| parent | driver core: Add device link support for SYNC_STATE_ONLY flag (diff) | |
| download | linux-dev-bcbbcfd57247f4c2976055995e5760fb576aae1e.tar.xz linux-dev-bcbbcfd57247f4c2976055995e5760fb576aae1e.zip | |
driver core: Allow a device to wait on optional suppliers
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@google.com>
Link: https://lore.kernel.org/r/20191028220027.251605-3-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/base/core.c')
| -rw-r--r-- | drivers/base/core.c | 28 |
1 files changed, 25 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); bus_probe_device(dev); if (parent) |