From: Saravana Kannan <saravanak@google.com>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"Rafael J. Wysocki" <rafael@kernel.org>,
Rob Herring <robh+dt@kernel.org>,
Frank Rowand <frowand.list@gmail.com>,
Len Brown <lenb@kernel.org>
Cc: Saravana Kannan <saravanak@google.com>,
kernel-team@android.com, linux-kernel@vger.kernel.org,
devicetree@vger.kernel.org, linux-acpi@vger.kernel.org
Subject: [PATCH v1 2/5] driver core: Allow a device to wait on optional suppliers
Date: Mon, 28 Oct 2019 15:00:23 -0700 [thread overview]
Message-ID: <20191028220027.251605-3-saravanak@google.com> (raw)
In-Reply-To: <20191028220027.251605-1-saravanak@google.com>
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>
---
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);
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;
};
--
2.24.0.rc0.303.g954a862665-goog
next prev parent reply other threads:[~2019-10-28 22:00 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-28 22:00 [PATCH v1 0/5] Improve of_devlink to handle "proxy cycles" Saravana Kannan
2019-10-28 22:00 ` [PATCH v1 1/5] driver core: Add device link support for SYNC_STATE_ONLY flag Saravana Kannan
2019-10-28 22:00 ` Saravana Kannan [this message]
2019-11-05 22:29 ` [PATCH v1 2/5] driver core: Allow a device to wait on optional suppliers Rafael J. Wysocki
2019-11-05 22:35 ` Saravana Kannan
2019-11-08 0:05 ` Rafael J. Wysocki
2019-11-08 0:08 ` Saravana Kannan
2019-10-28 22:00 ` [PATCH v1 3/5] driver core: Allow fwnode_operations.add_links to differentiate errors Saravana Kannan
2019-11-05 22:43 ` Rafael J. Wysocki
2019-11-05 22:52 ` Saravana Kannan
2019-11-05 23:07 ` Rafael J. Wysocki
2019-11-06 0:00 ` Saravana Kannan
2019-11-08 0:35 ` Rafael J. Wysocki
2019-11-13 2:06 ` Saravana Kannan
2019-10-28 22:00 ` [PATCH v1 4/5] of: property: Make sure child dependencies don't block probing of parent Saravana Kannan
2019-11-04 17:01 ` Rob Herring
2019-11-04 19:04 ` Saravana Kannan
2019-10-28 22:00 ` [PATCH v1 5/5] of: property: Skip adding device links to suppliers that aren't devices Saravana Kannan
2019-11-04 15:18 ` Rob Herring
2019-11-04 19:01 ` Saravana Kannan
2019-11-04 19:14 ` Rob Herring
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