linux-kernel - [RFC PATCH 1/2] driver core: add new dl device status DL_DEV_PROBE

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Date:   Thu, 29 Mar 2018 03:00:59 -0700
From:   Wang Dongsheng <dongsheng.wang@...-semitech.com>
To:     <rjw@...ysocki.net>, <lorenzo.pieralisi@....com>
CC:     <gregkh@...uxfoundation.org>, <hanjun.guo@...aro.org>,
        <sudeep.holla@....com>, <yu.zheng@...-semitech.com>,
        <linux-acpi@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        Wang Dongsheng <dongsheng.wang@...-semitech.com>
Subject: [RFC PATCH 1/2] driver core: add new dl device status DL_DEV_PROBE_FAILED

Currently the initialization state of device is DL_DEV_NO_DRIVER.
The problem is, after probe failure the state will also be set to
DL_DEV_NO_DRIVER as well. And the device is not linked, it has no
supplier or consumer. Thus adding a new state to distinguish
probe failure and not-probed-yet.

Signed-off-by: Wang Dongsheng <dongsheng.wang@...-semitech.com>
---
 Documentation/driver-api/device_link.rst |  2 +-
 drivers/base/base.h                      |  2 +-
 drivers/base/core.c                      | 22 ++++++++++++++++++++--
 drivers/base/dd.c                        |  2 +-
 include/linux/device.h                   |  1 +
 5 files changed, 24 insertions(+), 5 deletions(-)

diff --git a/Documentation/driver-api/device_link.rst b/Documentation/driver-api/device_link.rst
index 70e328e..9054403 100644
--- a/Documentation/driver-api/device_link.rst
+++ b/Documentation/driver-api/device_link.rst
@@ -247,7 +247,7 @@ State machine
   :c:func:`device_links_unbind_consumers()`.)
 
 * If the probe fails, links to suppliers revert back to ``DL_STATE_AVAILABLE``.
-  (Call to :c:func:`device_links_no_driver()` from :c:func:`really_probe()`.)
+  (Call to :c:func:`device_links_probe_failed()` from :c:func:`really_probe()`.)
 
 * If the probe succeeds, links to suppliers progress to ``DL_STATE_ACTIVE``.
   (Call to :c:func:`device_links_driver_bound()` from :c:func:`driver_bound()`.)
diff --git a/drivers/base/base.h b/drivers/base/base.h
index d800de6..f9931d9 100644
--- a/drivers/base/base.h
+++ b/drivers/base/base.h
@@ -158,6 +158,6 @@ extern void device_links_read_unlock(int idx);
 extern int device_links_check_suppliers(struct device *dev);
 extern void device_links_driver_bound(struct device *dev);
 extern void device_links_driver_cleanup(struct device *dev);
-extern void device_links_no_driver(struct device *dev);
+extern void device_links_probe_failed(struct device *dev);
 extern bool device_links_busy(struct device *dev);
 extern void device_links_unbind_consumers(struct device *dev);
diff --git a/drivers/base/core.c b/drivers/base/core.c
index 5847364..31d4f68 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -452,10 +452,28 @@ static void __device_links_no_driver(struct device *dev)
 	dev->links.status = DL_DEV_NO_DRIVER;
 }
 
-void device_links_no_driver(struct device *dev)
+static void __device_links_probe_failed(struct device *dev)
+{
+	struct device_link *link, *ln;
+
+	list_for_each_entry_safe_reverse(link, ln, &dev->links.suppliers,
+					 c_node) {
+		if (link->flags & DL_FLAG_STATELESS)
+			continue;
+
+		if (link->flags & DL_FLAG_AUTOREMOVE)
+			__device_link_del(link);
+		else if (link->status != DL_STATE_SUPPLIER_UNBIND)
+			WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
+	}
+
+	dev->links.status = DL_DEV_PROBE_FAILED;
+}
+
+void device_links_probe_failed(struct device *dev)
 {
 	device_links_write_lock();
-	__device_links_no_driver(dev);
+	__device_links_probe_failed(dev);
 	device_links_write_unlock();
 }
 
diff --git a/drivers/base/dd.c b/drivers/base/dd.c
index de6fd09..90d57e0 100644
--- a/drivers/base/dd.c
+++ b/drivers/base/dd.c
@@ -492,7 +492,7 @@ static int really_probe(struct device *dev, struct device_driver *drv)
 		blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
 					     BUS_NOTIFY_DRIVER_NOT_BOUND, dev);
 pinctrl_bind_failed:
-	device_links_no_driver(dev);
+	device_links_probe_failed(dev);
 	devres_release_all(dev);
 	driver_sysfs_remove(dev);
 	dev->driver = NULL;
diff --git a/include/linux/device.h b/include/linux/device.h
index b093405..bf9630a 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -794,6 +794,7 @@ struct device_link {
 enum dl_dev_state {
 	DL_DEV_NO_DRIVER = 0,
 	DL_DEV_PROBING,
+	DL_DEV_PROBE_FAILED,
 	DL_DEV_DRIVER_BOUND,
 	DL_DEV_UNBINDING,
 };
-- 
2.7.4