[PATCH v2] HID: lg4ff: Take advantage of private driver data

[Michal Malý <madcatxster@xxxxxxxxx>]

Hi,

this is a revised version of HID: lg4ff: Use Private Data I asked Simon to
submit for me earlier. To recap what the patch is about, it takes advantage
of the changes introduced in my patches from 2011/04/02. lg4ff now calls
hid_get/set_drvdata() to read or store device configuration. The way I understand
it, this is how all HID drivers store their private data. The change from the version
that was submitted earlier are removed all occurences of uninitialized_var() macro.

Please note that this patch depends on
"[PATCH v4] HID: hid-lg: Allow for custom device-specific properties to be stored in private drv data"
"[PATCH v4] HID: lg4ff: Remove sysfs iface before deallocating memory"

Signed-off-by: Michal Malý <madcatxster@xxxxxxxxx>

---
 drivers/hid/hid-lg4ff.c |   92 ++++++++++++++++++++++-------------------------
 1 file changed, 42 insertions(+), 50 deletions(-)

diff --git a/drivers/hid/hid-lg4ff.c b/drivers/hid/hid-lg4ff.c
index 1145292..32c173f 100644
--- a/drivers/hid/hid-lg4ff.c
+++ b/drivers/hid/hid-lg4ff.c
@@ -51,10 +51,7 @@ static ssize_t lg4ff_range_store(struct device *dev, struct device_attribute *at

 static DEVICE_ATTR(range, S_IRWXU | S_IRWXG | S_IRWXO, lg4ff_range_show, lg4ff_range_store);

-static bool list_inited;
-
 struct lg4ff_device_entry {
-	char  *device_id;	/* Use name in respective kobject structure's address as the ID */
 	__u16 range;
 	__u16 min_range;
 	__u16 max_range;
@@ -63,8 +60,6 @@ struct lg4ff_device_entry {
 	void (*set_range)(struct hid_device *hid, u16 range);
 };

-static struct lg4ff_device_entry device_list;
-
 static const signed short lg4ff_wheel_effects[] = {
 	FF_CONSTANT,
 	FF_AUTOCENTER,
@@ -285,18 +280,20 @@ static void hid_lg4ff_switch_native(struct hid_device *hid, const struct lg4ff_n
 /* Read current range and display it in terminal */
 static ssize_t lg4ff_range_show(struct device *dev, struct device_attribute *attr, char *buf)
 {
-	struct lg4ff_device_entry *uninitialized_var(entry);
-	struct list_head *h;
 	struct hid_device *hid = to_hid_device(dev);
+	struct lg4ff_device_entry *entry;
+	struct lg_drv_data *drv_data;
 	size_t count;

-	list_for_each(h, &device_list.list) {
-		entry = list_entry(h, struct lg4ff_device_entry, list);
-		if (strcmp(entry->device_id, (&hid->dev)->kobj.name) == 0)
-			break;
+	drv_data = hid_get_drvdata(hid);
+	if (!drv_data) {
+		hid_err(hid, "Private driver data not found!\n");
+		return 0;
 	}
-	if (h == &device_list.list) {
-		dbg_hid("Device not found!");
+
+	entry = drv_data->device_props;
+	if (!entry) {
+		hid_err(hid, "Device properties not found!\n");
 		return 0;
 	}

@@ -308,19 +305,21 @@ static ssize_t lg4ff_range_show(struct device *dev, struct device_attribute *att
  * according to the type of the wheel */
 static ssize_t lg4ff_range_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
 {
-	struct lg4ff_device_entry *uninitialized_var(entry);
-	struct list_head *h;
 	struct hid_device *hid = to_hid_device(dev);
+	struct lg4ff_device_entry *entry;
+	struct lg_drv_data *drv_data;
 	__u16 range = simple_strtoul(buf, NULL, 10);

-	list_for_each(h, &device_list.list) {
-		entry = list_entry(h, struct lg4ff_device_entry, list);
-		if (strcmp(entry->device_id, (&hid->dev)->kobj.name) == 0)
-			break;
+	drv_data = hid_get_drvdata(hid);
+	if (!drv_data) {
+		hid_err(hid, "Private driver data not found!\n");
+		return 0;
 	}
-	if (h == &device_list.list) {
-		dbg_hid("Device not found!");
-		return count;
+
+	entry = drv_data->device_props;
+	if (!entry) {
+		hid_err(hid, "Device properties not found!\n");
+		return 0;
 	}

 	if (range == 0)
@@ -344,6 +343,7 @@ int lg4ff_init(struct hid_device *hid)
 	struct hid_report *report;
 	struct hid_field *field;
 	struct lg4ff_device_entry *entry;
+	struct lg_drv_data *drv_data;
 	struct usb_device_descriptor *udesc;
 	int error, i, j;
 	__u16 bcdDevice, rev_maj, rev_min;
@@ -423,28 +423,24 @@ int lg4ff_init(struct hid_device *hid)
 		dev->ff->set_autocenter(dev, 0);
 	}

-		/* Initialize device_list if this is the first device to handle by lg4ff */
-	if (!list_inited) {
-		INIT_LIST_HEAD(&device_list.list);
-		list_inited = 1;
+	/* Get private driver data */
+	drv_data = hid_get_drvdata(hid);
+	if (!drv_data) {
+		hid_err(hid, "Cannot add device, private driver data not allocated\n");
+		return -1;
 	}

-	/* Add the device to device_list */
+	/* Initialize device properties */
 	entry = kzalloc(sizeof(struct lg4ff_device_entry), GFP_KERNEL);
 	if (!entry) {
-		hid_err(hid, "Cannot add device, insufficient memory.\n");
-		return -ENOMEM;
-	}
-	entry->device_id = kstrdup((&hid->dev)->kobj.name, GFP_KERNEL);
-	if (!entry->device_id) {
-		hid_err(hid, "Cannot set device_id, insufficient memory.\n");
-		kfree(entry);
+		hid_err(hid, "Cannot add device, insufficient memory to allocate device properties.\n");
 		return -ENOMEM;
 	}
+	drv_data->device_props = entry;
+
 	entry->min_range = lg4ff_devices[i].min_range;
 	entry->max_range = lg4ff_devices[i].max_range;
 	entry->set_range = lg4ff_devices[i].set_range;
-	list_add(&entry->list, &device_list.list);

 	/* Create sysfs interface */
 	error = device_create_file(&hid->dev, &dev_attr_range);
@@ -463,27 +459,23 @@ int lg4ff_init(struct hid_device *hid)

 int lg4ff_deinit(struct hid_device *hid)
 {
-	bool found = 0;
 	struct lg4ff_device_entry *entry;
-	struct list_head *h, *g;
-
+	struct lg_drv_data *drv_data;
+
 	device_remove_file(&hid->dev, &dev_attr_range);

-	list_for_each_safe(h, g, &device_list.list) {
-		entry = list_entry(h, struct lg4ff_device_entry, list);
-		if (strcmp(entry->device_id, (&hid->dev)->kobj.name) == 0) {
-			list_del(h);
-			kfree(entry->device_id);
-			kfree(entry);
-			found = 1;
-			break;
-		}
+	drv_data = hid_get_drvdata(hid);
+	if (!drv_data) {
+		hid_err(hid, "Error while deinitializing device, no private driver data.\n");
+		return -1;
 	}
-
-	if (!found) {
-		hid_err(hid, "Device entry not found!\n");
+	entry = drv_data->device_props;
+	if (!entry) {
+		hid_err(hid, "Error while deinitializing device, no device properties data.\n");
 		return -1;
 	}
+	/* Deallocate memory */
+	kfree(entry);

 	dbg_hid("Device successfully unregistered\n");
 	return 0;
--
1.7.9.6

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