[PATCH 03/14] i8k: Convert to use to hwmon_device_register_with_groups hwmon API

Guenter Roeck
2013-12-14T17:31:13Z

Simplify code and fix race condition caused by registering
hwmon device prior to creating sysfs attributes.

Cc: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
drivers/char/i8k.c | 132 +++++++++++++++++++++-------------------------------
1 file changed, 54 insertions(+), 78 deletions(-)

diff --git a/drivers/char/i8k.c b/drivers/char/i8k.c
index 71da6b7..d2acbb8 100644
--- a/drivers/char/i8k.c
+++ b/drivers/char/i8k.c
@@ -66,6 +66,11 @@
static DEFINE_MUTEX(i8k_mutex);
static char bios_version[4];
static struct device *i8k_hwmon_dev;
+static u32 i8k_hwmon_flags;
+
+#define I8K_HWMON_HAVE_TEMP1 (1 << 0)
+#define I8K_HWMON_HAVE_FAN1 (1 << 1)
+#define I8K_HWMON_HAVE_FAN2 (1 << 2)

MODULE_AUTHOR("Massimo Dal Zotto (dz@debian.org)");
MODULE_DESCRIPTION("Driver for accessing SMM BIOS on Dell laptops");
@@ -502,8 +507,7 @@ static ssize_t i8k_hwmon_show_label(struct device *dev,
struct device_attribute *devattr,
char *buf)
{
- static const char *labels[4] = {
- "i8k",
+ static const char *labels[3] = {
"CPU",
"Left Fan",
"Right Fan",
@@ -518,100 +522,72 @@ static SENSOR_DEVICE_ATTR(fan1_input, S_IRUGO, i8k_hwmon_show_fan, NULL,
I8K_FAN_LEFT);
static SENSOR_DEVICE_ATTR(fan2_input, S_IRUGO, i8k_hwmon_show_fan, NULL,
I8K_FAN_RIGHT);
-static SENSOR_DEVICE_ATTR(name, S_IRUGO, i8k_hwmon_show_label, NULL, 0);
-static SENSOR_DEVICE_ATTR(temp1_label, S_IRUGO, i8k_hwmon_show_label, NULL, 1);
-static SENSOR_DEVICE_ATTR(fan1_label, S_IRUGO, i8k_hwmon_show_label, NULL, 2);
-static SENSOR_DEVICE_ATTR(fan2_label, S_IRUGO, i8k_hwmon_show_label, NULL, 3);
+static SENSOR_DEVICE_ATTR(temp1_label, S_IRUGO, i8k_hwmon_show_label, NULL, 0);
+static SENSOR_DEVICE_ATTR(fan1_label, S_IRUGO, i8k_hwmon_show_label, NULL, 1);
+static SENSOR_DEVICE_ATTR(fan2_label, S_IRUGO, i8k_hwmon_show_label, NULL, 2);
+
+static struct attribute *i8k_attrs[] = {
+ &dev_attr_temp1_input.attr, /* 0 */
+ &sensor_dev_attr_temp1_label.dev_attr.attr, /* 1 */
+ &sensor_dev_attr_fan1_input.dev_attr.attr, /* 2 */
+ &sensor_dev_attr_fan1_label.dev_attr.attr, /* 3 */
+ &sensor_dev_attr_fan2_input.dev_attr.attr, /* 4 */
+ &sensor_dev_attr_fan2_label.dev_attr.attr, /* 5 */
+ NULL
+};

-static void i8k_hwmon_remove_files(struct device *dev)
+static umode_t i8k_is_visible(struct kobject *kobj, struct attribute *attr,
+ int index)
{
- device_remove_file(dev, &dev_attr_temp1_input);
- device_remove_file(dev, &sensor_dev_attr_fan1_input.dev_attr);
- device_remove_file(dev, &sensor_dev_attr_fan2_input.dev_attr);
- device_remove_file(dev, &sensor_dev_attr_temp1_label.dev_attr);
- device_remove_file(dev, &sensor_dev_attr_fan1_label.dev_attr);
- device_remove_file(dev, &sensor_dev_attr_fan2_label.dev_attr);
- device_remove_file(dev, &sensor_dev_attr_name.dev_attr);
+ if ((index == 0 || index == 1) &&
+ !(i8k_hwmon_flags & I8K_HWMON_HAVE_TEMP1))
+ return 0;
+ if ((index == 2 || index == 3) &&
+ !(i8k_hwmon_flags & I8K_HWMON_HAVE_FAN1))
+ return 0;
+ if ((index == 4 || index == 5) &&
+ !(i8k_hwmon_flags & I8K_HWMON_HAVE_FAN2))
+ return 0;
+
+ return attr->mode;
}

+static const struct attribute_group i8k_group = {
+ .attrs = i8k_attrs,
+ .is_visible = i8k_is_visible,
+};
+__ATTRIBUTE_GROUPS(i8k);
+
static int __init i8k_init_hwmon(void)
{
int err;

- i8k_hwmon_dev = hwmon_device_register(NULL);
- if (IS_ERR(i8k_hwmon_dev)) {
- err = PTR_ERR(i8k_hwmon_dev);
- i8k_hwmon_dev = NULL;
- pr_err("hwmon registration failed (%d)\n", err);
- return err;
- }
-
- /* Required name attribute */
- err = device_create_file(i8k_hwmon_dev,
- &sensor_dev_attr_name.dev_attr);
- if (err)
- goto exit_unregister;
+ i8k_hwmon_flags = 0;

/* CPU temperature attributes, if temperature reading is OK */
err = i8k_get_temp(0);
- if (err < 0) {
- dev_dbg(i8k_hwmon_dev,
- "Not creating temperature attributes (%d)\n", err);
- } else {
- err = device_create_file(i8k_hwmon_dev, &dev_attr_temp1_input);
- if (err)
- goto exit_remove_files;
- err = device_create_file(i8k_hwmon_dev,
- &sensor_dev_attr_temp1_label.dev_attr);
- if (err)
- goto exit_remove_files;
- }
+ if (err >= 0)
+ i8k_hwmon_flags |= I8K_HWMON_HAVE_TEMP1;

/* Left fan attributes, if left fan is present */
err = i8k_get_fan_status(I8K_FAN_LEFT);
- if (err < 0) {
- dev_dbg(i8k_hwmon_dev,
- "Not creating %s fan attributes (%d)\n", "left", err);
- } else {
- err = device_create_file(i8k_hwmon_dev,
- &sensor_dev_attr_fan1_input.dev_attr);
- if (err)
- goto exit_remove_files;
- err = device_create_file(i8k_hwmon_dev,
- &sensor_dev_attr_fan1_label.dev_attr);
- if (err)
- goto exit_remove_files;
- }
+ if (err >= 0)
+ i8k_hwmon_flags |= I8K_HWMON_HAVE_FAN1;

/* Right fan attributes, if right fan is present */
err = i8k_get_fan_status(I8K_FAN_RIGHT);
- if (err < 0) {
- dev_dbg(i8k_hwmon_dev,
- "Not creating %s fan attributes (%d)\n", "right", err);
- } else {
- err = device_create_file(i8k_hwmon_dev,
- &sensor_dev_attr_fan2_input.dev_attr);
- if (err)
- goto exit_remove_files;
- err = device_create_file(i8k_hwmon_dev,
- &sensor_dev_attr_fan2_label.dev_attr);
- if (err)
- goto exit_remove_files;
- }
+ if (err >= 0)
+ i8k_hwmon_flags |= I8K_HWMON_HAVE_FAN2;

+ i8k_hwmon_dev = hwmon_device_register_with_groups(NULL, "i8k", NULL,
+ i8k_groups);
+ if (IS_ERR(i8k_hwmon_dev)) {
+ err = PTR_ERR(i8k_hwmon_dev);
+ i8k_hwmon_dev = NULL;
+ pr_err("hwmon registration failed (%d)\n", err);
+ return err;
+ }
return 0;
-
- exit_remove_files:
- i8k_hwmon_remove_files(i8k_hwmon_dev);
- exit_unregister:
- hwmon_device_unregister(i8k_hwmon_dev);
- return err;
-}
-
-static void __exit i8k_exit_hwmon(void)
-{
- i8k_hwmon_remove_files(i8k_hwmon_dev);
- hwmon_device_unregister(i8k_hwmon_dev);
}

static struct dmi_system_id i8k_dmi_table[] __initdata = {
@@ -767,7 +743,7 @@ static int __init i8k_init(void)

static void __exit i8k_exit(void)
{
- i8k_exit_hwmon();
+ hwmon_device_unregister(i8k_hwmon_dev);
remove_proc_entry("i8k", NULL);
}

--
1.7.9.7