[PATCH 1/3] HID: logitech-hidpp: use devres to manage FF private data

[Andrey Smirnov]

To simplify resource management in commit that follows as well as to
save a couple of extra kfree()s and simplify hidpp_ff_deinit() switch
driver code to use devres to manage the life-cycle of FF private data.

Signed-off-by: Andrey Smirnov <andrew.smir...@gmail.com>
Cc: Jiri Kosina <ji...@kernel.org>
Cc: Benjamin Tissoires <benjamin.tissoi...@redhat.com>
Cc: Henrik Rydberg <rydb...@bitmath.org>
Cc: Sam Bazely <sambaz...@fastmail.com>
Cc: Pierre-Loup A. Griffais <pgriff...@valvesoftware.com>
Cc: Austin Palmer <aust...@valvesoftware.com>
Cc: linux-in...@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: sta...@vger.kernel.org
---
 drivers/hid/hid-logitech-hidpp.c | 53 +++++++++++++++++---------------
 1 file changed, 29 insertions(+), 24 deletions(-)

diff --git a/drivers/hid/hid-logitech-hidpp.c b/drivers/hid/hid-logitech-hidpp.c
index 0179f7ed77e5..58eb928224e5 100644
--- a/drivers/hid/hid-logitech-hidpp.c
+++ b/drivers/hid/hid-logitech-hidpp.c
@@ -2079,6 +2079,11 @@ static void hidpp_ff_destroy(struct ff_device *ff)
        struct hidpp_ff_private_data *data = ff->private;
 
        kfree(data->effect_ids);
+       /*
+        * Set private to NULL to prevent input_ff_destroy() from
+        * freeing our devres allocated memory
+        */
+       ff->private = NULL;
 }
 
 static int hidpp_ff_init(struct hidpp_device *hidpp, u8 feature_index)
@@ -2090,7 +2095,7 @@ static int hidpp_ff_init(struct hidpp_device *hidpp, u8 
feature_index)
        const u16 bcdDevice = le16_to_cpu(udesc->bcdDevice);
        struct ff_device *ff;
        struct hidpp_report response;
-       struct hidpp_ff_private_data *data;
+       struct hidpp_ff_private_data *data = hidpp->private_data;
        int error, j, num_slots;
        u8 version;
 
@@ -2129,18 +2134,13 @@ static int hidpp_ff_init(struct hidpp_device *hidpp, u8 
feature_index)
                return error;
        }
 
-       data = kzalloc(sizeof(*data), GFP_KERNEL);
-       if (!data)
-               return -ENOMEM;
        data->effect_ids = kcalloc(num_slots, sizeof(int), GFP_KERNEL);
-       if (!data->effect_ids) {
-               kfree(data);
+       if (!data->effect_ids)
                return -ENOMEM;
-       }
+
        data->wq = create_singlethread_workqueue("hidpp-ff-sendqueue");
        if (!data->wq) {
                kfree(data->effect_ids);
-               kfree(data);
                return -ENOMEM;
        }
 
@@ -2199,28 +2199,15 @@ static int hidpp_ff_init(struct hidpp_device *hidpp, u8 
feature_index)
        return 0;
 }
 
-static int hidpp_ff_deinit(struct hid_device *hid)
+static void hidpp_ff_deinit(struct hid_device *hid)
 {
-       struct hid_input *hidinput = list_entry(hid->inputs.next, struct 
hid_input, list);
-       struct input_dev *dev = hidinput->input;
-       struct hidpp_ff_private_data *data;
-
-       if (!dev) {
-               hid_err(hid, "Struct input_dev not found!\n");
-               return -EINVAL;
-       }
+       struct hidpp_device *hidpp = hid_get_drvdata(hid);
+       struct hidpp_ff_private_data *data = hidpp->private_data;
 
        hid_info(hid, "Unloading HID++ force feedback.\n");
-       data = dev->ff->private;
-       if (!data) {
-               hid_err(hid, "Private data not found!\n");
-               return -EINVAL;
-       }
 
        destroy_workqueue(data->wq);
        device_remove_file(&hid->dev, &dev_attr_range);
-
-       return 0;
 }
 
 
@@ -2725,6 +2712,20 @@ static int k400_connect(struct hid_device *hdev, bool 
connected)
 
 #define HIDPP_PAGE_G920_FORCE_FEEDBACK                 0x8123
 
+static int g920_allocate(struct hid_device *hdev)
+{
+       struct hidpp_device *hidpp = hid_get_drvdata(hdev);
+       struct hidpp_ff_private_data *data;
+
+       data = devm_kzalloc(&hdev->dev, sizeof(*data), GFP_KERNEL);
+       if (!data)
+               return -ENOMEM;
+
+       hidpp->private_data = data;
+
+       return 0;
+}
+
 static int g920_get_config(struct hidpp_device *hidpp)
 {
        u8 feature_type;
@@ -3561,6 +3562,10 @@ static int hidpp_probe(struct hid_device *hdev, const 
struct hid_device_id *id)
                ret = k400_allocate(hdev);
                if (ret)
                        return ret;
+       } else if (hidpp->quirks & HIDPP_QUIRK_CLASS_G920) {
+               ret = g920_allocate(hdev);
+               if (ret)
+                       return ret;
        }
 
        INIT_WORK(&hidpp->work, delayed_work_cb);
-- 
2.21.0