i2c: __must_check fixes (chip drivers)

i2c: __must_check fixes (chip drivers)

Check for error on sysfs file creation.
Delete sysfs files on device removal.

The approach taken for the most complex case (pcf8591) is similar to
what Mark M. Hoffman proposed for hardware monitoring chip drivers.

Signed-off-by: Jean Delvare <[e-mail]>
Cc: Ben Gardner <[e-mail]>
Cc: Aurelien Jarno <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/i2c/chips/eeprom.c

···
 	}
 
 	/* create the sysfs eeprom file */
-	sysfs_create_bin_file(&new_client->dev.kobj, &eeprom_attr);
+	err = sysfs_create_bin_file(&new_client->dev.kobj, &eeprom_attr);
+	if (err)
+		goto exit_detach;
 
 	return 0;
 
+exit_detach:
+	i2c_detach_client(new_client);
 exit_kfree:
 	kfree(data);
 exit:
···
 static int eeprom_detach_client(struct i2c_client *client)
 {
 	int err;
+
+	sysfs_remove_bin_file(&client->dev.kobj, &eeprom_attr);
 
 	err = i2c_detach_client(client);
 	if (err)

drivers/i2c/chips/max6875.c

···
 	mutex_init(&data->update_lock);
 
 	/* Init fake client data */
-	/* set the client data to the i2c_client so that it will get freed */
-	i2c_set_clientdata(fake_client, fake_client);
+	i2c_set_clientdata(fake_client, NULL);
 	fake_client->addr = address | 1;
 	fake_client->adapter = adapter;
 	fake_client->driver = &max6875_driver;
···
 		goto exit_kfree2;
 
 	if ((err = i2c_attach_client(fake_client)) != 0)
-		goto exit_detach;
+		goto exit_detach1;
 
-	sysfs_create_bin_file(&real_client->dev.kobj, &user_eeprom_attr);
+	err = sysfs_create_bin_file(&real_client->dev.kobj, &user_eeprom_attr);
+	if (err)
+		goto exit_detach2;
 
 	return 0;
 
-exit_detach:
+exit_detach2:
+	i2c_detach_client(fake_client);
+exit_detach1:
 	i2c_detach_client(real_client);
 exit_kfree2:
 	kfree(fake_client);
···
 	return err;
 }
 
+/* Will be called for both the real client and the fake client */
 static int max6875_detach_client(struct i2c_client *client)
 {
 	int err;
+	struct max6875_data *data = i2c_get_clientdata(client);
+
+	/* data is NULL for the fake client */
+	if (data)
+		sysfs_remove_bin_file(&client->dev.kobj, &user_eeprom_attr);
 
 	err = i2c_detach_client(client);
 	if (err)
 		return err;
-	kfree(i2c_get_clientdata(client));
+
+	if (data)		/* real client */
+		kfree(data);
+	else			/* fake client */
+		kfree(client);
 	return 0;
 }
 

drivers/i2c/chips/pca9539.c

···
 	if ((err = i2c_attach_client(new_client)))
 		goto exit_kfree;
 
-	/* Register sysfs hooks (don't care about failure) */
-	sysfs_create_group(&new_client->dev.kobj, &pca9539_defattr_group);
+	/* Register sysfs hooks */
+	err = sysfs_create_group(&new_client->dev.kobj,
+				 &pca9539_defattr_group);
+	if (err)
+		goto exit_detach;
 
 	return 0;
 
+exit_detach:
+	i2c_detach_client(new_client);
 exit_kfree:
 	kfree(data);
 exit:
···
 static int pca9539_detach_client(struct i2c_client *client)
 {
 	int err;
+
+	sysfs_remove_group(&client->dev.kobj, &pca9539_defattr_group);
 
 	if ((err = i2c_detach_client(client)))
 		return err;

drivers/i2c/chips/pcf8574.c

···
 
 static DEVICE_ATTR(write, S_IWUSR | S_IRUGO, show_write, set_write);
 
+static struct attribute *pcf8574_attributes[] = {
+	&dev_attr_read.attr,
+	&dev_attr_write.attr,
+	NULL
+};
+
+static const struct attribute_group pcf8574_attr_group = {
+	.attrs = pcf8574_attributes,
+};
+
 /*
  * Real code
  */
···
 	pcf8574_init_client(new_client);
 
 	/* Register sysfs hooks */
-	device_create_file(&new_client->dev, &dev_attr_read);
-	device_create_file(&new_client->dev, &dev_attr_write);
+	err = sysfs_create_group(&new_client->dev.kobj, &pcf8574_attr_group);
+	if (err)
+		goto exit_detach;
 	return 0;
 
-/* OK, this is not exactly good programming practice, usually. But it is
-   very code-efficient in this case. */
-
+      exit_detach:
+	i2c_detach_client(new_client);
       exit_free:
 	kfree(data);
       exit:
···
 static int pcf8574_detach_client(struct i2c_client *client)
 {
 	int err;
+
+	sysfs_remove_group(&client->dev.kobj, &pcf8574_attr_group);
 
 	if ((err = i2c_detach_client(client)))
 		return err;

drivers/i2c/chips/pcf8591.c

···
 static DEVICE_ATTR(out0_enable, S_IWUSR | S_IRUGO, 
 		   show_out0_enable, set_out0_enable);
 
+static struct attribute *pcf8591_attributes[] = {
+	&dev_attr_out0_enable.attr,
+	&dev_attr_out0_output.attr,
+	&dev_attr_in0_input.attr,
+	&dev_attr_in1_input.attr,
+	NULL
+};
+
+static const struct attribute_group pcf8591_attr_group = {
+	.attrs = pcf8591_attributes,
+};
+
+static struct attribute *pcf8591_attributes_opt[] = {
+	&dev_attr_in2_input.attr,
+	&dev_attr_in3_input.attr,
+	NULL
+};
+
+static const struct attribute_group pcf8591_attr_group_opt = {
+	.attrs = pcf8591_attributes_opt,
+};
+
 /*
  * Real code
  */
···
 	pcf8591_init_client(new_client);
 
 	/* Register sysfs hooks */
-	device_create_file(&new_client->dev, &dev_attr_out0_enable);
-	device_create_file(&new_client->dev, &dev_attr_out0_output);
-	device_create_file(&new_client->dev, &dev_attr_in0_input);
-	device_create_file(&new_client->dev, &dev_attr_in1_input);
+	err = sysfs_create_group(&new_client->dev.kobj, &pcf8591_attr_group);
+	if (err)
+		goto exit_detach;
 
 	/* Register input2 if not in "two differential inputs" mode */
-	if (input_mode != 3 )
-		device_create_file(&new_client->dev, &dev_attr_in2_input);
-		
-	/* Register input3 only in "four single ended inputs" mode */
-	if (input_mode == 0)
-		device_create_file(&new_client->dev, &dev_attr_in3_input);
-	
-	return 0;
-	
-	/* OK, this is not exactly good programming practice, usually. But it is
-	   very code-efficient in this case. */
+	if (input_mode != 3) {
+		if ((err = device_create_file(&new_client->dev,
+					      &dev_attr_in2_input)))
+			goto exit_sysfs_remove;
+	}
 
+	/* Register input3 only in "four single ended inputs" mode */
+	if (input_mode == 0) {
+		if ((err = device_create_file(&new_client->dev,
+					      &dev_attr_in3_input)))
+			goto exit_sysfs_remove;
+	}
+
+	return 0;
+
+exit_sysfs_remove:
+	sysfs_remove_group(&new_client->dev.kobj, &pcf8591_attr_group_opt);
+	sysfs_remove_group(&new_client->dev.kobj, &pcf8591_attr_group);
+exit_detach:
+	i2c_detach_client(new_client);
 exit_kfree:
 	kfree(data);
 exit:
···
 static int pcf8591_detach_client(struct i2c_client *client)
 {
 	int err;
+
+	sysfs_remove_group(&client->dev.kobj, &pcf8591_attr_group_opt);
+	sysfs_remove_group(&client->dev.kobj, &pcf8591_attr_group);
 
 	if ((err = i2c_detach_client(client)))
 		return err;