linux-kernel - [PATCH] counter: Stop using dev_get_drvdata() to get the counter device

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Date:   Fri,  4 Feb 2022 09:25:56 +0100
From:   Uwe Kleine-König 
        <u.kleine-koenig@...gutronix.de>
To:     William Breathitt Gray <vilhelm.gray@...il.com>
Cc:     linux-iio@...r.kernel.org,
        Robin van der Gracht <robin@...tonic.nl>,
        linux-kernel@...r.kernel.org,
        Oleksij Rempel <o.rempel@...gutronix.de>,
        Pengutronix Kernel Team <kernel@...gutronix.de>,
        David Jander <david@...tonic.nl>,
        Jonathan Cameron <jic23@...nel.org>
Subject: [PATCH] counter: Stop using dev_get_drvdata() to get the counter device

dev_get_drvdata() returns NULL since commit b56346ddbd82 ("counter: Use
container_of instead of drvdata to track counter_device") which wrongly
claimed there were no users of drvdata. Convert to container_of() to
fix a null pointer dereference.

Reported-by: Oleksij Rempel <o.rempel@...gutronix.de>
Fixes: b56346ddbd82 ("counter: Use container_of instead of drvdata to track counter_device")
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@...gutronix.de>
---
 drivers/counter/counter-sysfs.c | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/drivers/counter/counter-sysfs.c b/drivers/counter/counter-sysfs.c
index 7cc4d1d523ea..04eac41dad33 100644
--- a/drivers/counter/counter-sysfs.c
+++ b/drivers/counter/counter-sysfs.c
@@ -19,6 +19,11 @@
 
 #include "counter-sysfs.h"
 
+static inline struct counter_device *counter_from_dev(struct device *dev)
+{
+	return container_of(dev, struct counter_device, dev);
+}
+
 /**
  * struct counter_attribute - Counter sysfs attribute
  * @dev_attr:	device attribute for sysfs
@@ -90,7 +95,7 @@ static ssize_t counter_comp_u8_show(struct device *dev,
 				    struct device_attribute *attr, char *buf)
 {
 	const struct counter_attribute *const a = to_counter_attribute(attr);
-	struct counter_device *const counter = dev_get_drvdata(dev);
+	struct counter_device *const counter = counter_from_dev(dev);
 	int err;
 	u8 data = 0;
 
@@ -122,7 +127,7 @@ static ssize_t counter_comp_u8_store(struct device *dev,
 				     const char *buf, size_t len)
 {
 	const struct counter_attribute *const a = to_counter_attribute(attr);
-	struct counter_device *const counter = dev_get_drvdata(dev);
+	struct counter_device *const counter = counter_from_dev(dev);
 	int err;
 	bool bool_data = 0;
 	u8 data = 0;
@@ -158,7 +163,7 @@ static ssize_t counter_comp_u32_show(struct device *dev,
 				     struct device_attribute *attr, char *buf)
 {
 	const struct counter_attribute *const a = to_counter_attribute(attr);
-	struct counter_device *const counter = dev_get_drvdata(dev);
+	struct counter_device *const counter = counter_from_dev(dev);
 	const struct counter_available *const avail = a->comp.priv;
 	int err;
 	u32 data = 0;
@@ -221,7 +226,7 @@ static ssize_t counter_comp_u32_store(struct device *dev,
 				      const char *buf, size_t len)
 {
 	const struct counter_attribute *const a = to_counter_attribute(attr);
-	struct counter_device *const counter = dev_get_drvdata(dev);
+	struct counter_device *const counter = counter_from_dev(dev);
 	struct counter_count *const count = a->parent;
 	struct counter_synapse *const synapse = a->comp.priv;
 	const struct counter_available *const avail = a->comp.priv;
@@ -281,7 +286,7 @@ static ssize_t counter_comp_u64_show(struct device *dev,
 				     struct device_attribute *attr, char *buf)
 {
 	const struct counter_attribute *const a = to_counter_attribute(attr);
-	struct counter_device *const counter = dev_get_drvdata(dev);
+	struct counter_device *const counter = counter_from_dev(dev);
 	int err;
 	u64 data = 0;
 
@@ -309,7 +314,7 @@ static ssize_t counter_comp_u64_store(struct device *dev,
 				      const char *buf, size_t len)
 {
 	const struct counter_attribute *const a = to_counter_attribute(attr);
-	struct counter_device *const counter = dev_get_drvdata(dev);
+	struct counter_device *const counter = counter_from_dev(dev);
 	int err;
 	u64 data = 0;
 

base-commit: e783362eb54cd99b2cac8b3a9aeac942e6f6ac07
-- 
2.34.1