linux-kernel - [PATCH] PM / wakeup: Register wakeup class kobj after device is added

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Message-Id: <20190816145602.231163-1-swboyd@chromium.org>
Date:   Fri, 16 Aug 2019 07:56:02 -0700
From:   Stephen Boyd <swboyd@...omium.org>
To:     "Rafael J. Wysocki" <rjw@...ysocki.net>
Cc:     linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
        Qian Cai <cai@....pw>, Tri Vo <trong@...roid.com>
Subject: [PATCH] PM / wakeup: Register wakeup class kobj after device is added

The device_set_wakeup_enable() function can be called on a device that
hasn't been registered with device_add() yet. This allows the device to
be in a state where wakeup is enabled for it but the device isn't
published to userspace in sysfs yet.

After commit 986845e747af ("PM / wakeup: Show wakeup sources stats in
sysfs"), calling device_set_wakeup_enable() will fail for a device that
hasn't been registered with the driver core via device_add(). This is
because we try to create sysfs entries for the device and associate a
wakeup class kobject with it before the device has been registered.
Let's follow a similar approach that device_set_wakeup_capable() takes
here and register the wakeup class either from
device_set_wakeup_enable() when the device is already registered, or
from dpm_sysfs_add() when the device is being registered with the driver
core via device_add().

Fixes: 986845e747af ("PM / wakeup: Show wakeup sources stats in sysfs")
Reported-by: Qian Cai <cai@....pw>
Cc: Qian Cai <cai@....pw>
Cc: Tri Vo <trong@...roid.com>
Signed-off-by: Stephen Boyd <swboyd@...omium.org>
---
 drivers/base/power/sysfs.c  | 10 +++++++++-
 drivers/base/power/wakeup.c | 10 ++++++----
 2 files changed, 15 insertions(+), 5 deletions(-)

diff --git a/drivers/base/power/sysfs.c b/drivers/base/power/sysfs.c
index 1b9c281cbe41..27ee00f50bd7 100644
--- a/drivers/base/power/sysfs.c
+++ b/drivers/base/power/sysfs.c
@@ -5,6 +5,7 @@
 #include <linux/export.h>
 #include <linux/pm_qos.h>
 #include <linux/pm_runtime.h>
+#include <linux/pm_wakeup.h>
 #include <linux/atomic.h>
 #include <linux/jiffies.h>
 #include "power.h"
@@ -661,14 +662,21 @@ int dpm_sysfs_add(struct device *dev)
 		if (rc)
 			goto err_runtime;
 	}
+	if (dev->power.wakeup) {
+		rc = wakeup_source_sysfs_add(dev, dev->power.wakeup);
+		if (rc)
+			goto err_wakeup;
+	}
 	if (dev->power.set_latency_tolerance) {
 		rc = sysfs_merge_group(&dev->kobj,
 				       &pm_qos_latency_tolerance_attr_group);
 		if (rc)
-			goto err_wakeup;
+			goto err_wakeup_source;
 	}
 	return 0;
 
+ err_wakeup_source:
+	wakeup_source_sysfs_remove(dev->power.wakeup);
  err_wakeup:
 	sysfs_unmerge_group(&dev->kobj, &pm_wakeup_attr_group);
  err_runtime:
diff --git a/drivers/base/power/wakeup.c b/drivers/base/power/wakeup.c
index f7925820b5ca..5817b51d2b15 100644
--- a/drivers/base/power/wakeup.c
+++ b/drivers/base/power/wakeup.c
@@ -220,10 +220,12 @@ struct wakeup_source *wakeup_source_register(struct device *dev,
 
 	ws = wakeup_source_create(name);
 	if (ws) {
-		ret = wakeup_source_sysfs_add(dev, ws);
-		if (ret) {
-			wakeup_source_free(ws);
-			return NULL;
+		if (!dev || device_is_registered(dev)) {
+			ret = wakeup_source_sysfs_add(dev, ws);
+			if (ret) {
+				wakeup_source_free(ws);
+				return NULL;
+			}
 		}
 		wakeup_source_add(ws);
 	}
-- 
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