linux-kernel - [PATCH v2] hid-elo: update the reference count of the usb device structure

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Message-ID: <20210725132858.GA614754@pc>
Date:   Sun, 25 Jul 2021 14:28:58 +0100
From:   Salah Triki <salah.triki@...il.com>
To:     Jiri Kosina <jikos@...nel.org>,
        Benjamin Tissoires <benjamin.tissoires@...hat.com>,
        gregkh@...uxfoundation.org
Cc:     linux-input@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH v2] hid-elo: update the reference count of the usb device
 structure

Use usb_get_dev() to increment the reference count of the usb device
structure in order to avoid releasing the structure while it is still in
use. And use usb_put_dev() to decrement the reference count and thus,
when it will be equal to 0 the structure will be released.

Signed-off-by: Salah Triki <salah.triki@...il.com>
---
Change since v1:
	Modification of the description

 drivers/hid/hid-elo.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/hid/hid-elo.c b/drivers/hid/hid-elo.c
index 0d22713a3874..383dfda8c12f 100644
--- a/drivers/hid/hid-elo.c
+++ b/drivers/hid/hid-elo.c
@@ -228,13 +228,15 @@ static int elo_probe(struct hid_device *hdev, const struct hid_device_id *id)
 {
 	struct elo_priv *priv;
 	int ret;
+	struct usb_device *udev;
 
 	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
 	if (!priv)
 		return -ENOMEM;
 
 	INIT_DELAYED_WORK(&priv->work, elo_work);
-	priv->usbdev = interface_to_usbdev(to_usb_interface(hdev->dev.parent));
+	udev = interface_to_usbdev(to_usb_interface(hdev->dev.parent));
+	priv->usbdev = usb_get_dev(udev);
 
 	hid_set_drvdata(hdev, priv);
 
@@ -265,6 +267,8 @@ static void elo_remove(struct hid_device *hdev)
 {
 	struct elo_priv *priv = hid_get_drvdata(hdev);
 
+	usb_put_dev(priv->usbdev);
+
 	hid_hw_stop(hdev);
 	cancel_delayed_work_sync(&priv->work);
 	kfree(priv);
-- 
2.25.1