Input: alps - use guard notation when acquiring mutex

This makes the code more compact and error handling more robust by ensuring that mutexes are released in all code paths when control leaves critical section.

Signed-off-by Dmitry Torokhov <[email protected]>

---
 drivers/input/mouse/alps.c | 48 +++++++++++++++++++++-----------------
 1 file changed, 27 insertions(+), 21 deletions(-)

drivers/input/mouse/alps.c +27 -21

index d5ef5a112d6f..4e37fc3f1a9e 100644
@@ -1396,24 +1396,16 @@ static bool alps_is_valid_package_ss4_v2(struct psmouse *psmouse)
 
 static DEFINE_MUTEX(alps_mutex);
 
-static void alps_register_bare_ps2_mouse(struct work_struct *work)
+static int alps_do_register_bare_ps2_mouse(struct alps_data *priv)
 {
-	struct alps_data *priv =
-		container_of(work, struct alps_data, dev3_register_work.work);
 	struct psmouse *psmouse = priv->psmouse;
 	struct input_dev *dev3;
-	int error = 0;
-
-	mutex_lock(&alps_mutex);
-
-	if (priv->dev3)
-		goto out;
+	int error;
 
 	dev3 = input_allocate_device();
 	if (!dev3) {
 		psmouse_err(psmouse, "failed to allocate secondary device\n");
-		error = -ENOMEM;
-		goto out;
+		return -ENOMEM;
 	}
 
 	snprintf(priv->phys3, sizeof(priv->phys3), "%s/%s",

@@ -1446,21 +1438,35 @@ static void alps_register_bare_ps2_mouse(struct work_struct *work)
 		psmouse_err(psmouse,
 			    "failed to register secondary device: %d\n",
 			    error);
-		input_free_device(dev3);
-		goto out;
+		goto err_free_input;
 	}
 
 	priv->dev3 = dev3;
+	return 0;
 
-out:
-	/*
-	 * Save the error code so that we can detect that we
-	 * already tried to create the device.
-	 */
-	if (error)
-		priv->dev3 = ERR_PTR(error);
+err_free_input:
+	input_free_device(dev3);
+	return error;
+}
 
-	mutex_unlock(&alps_mutex);
+static void alps_register_bare_ps2_mouse(struct work_struct *work)
+{
+	struct alps_data *priv = container_of(work, struct alps_data,
+					      dev3_register_work.work);
+	int error;
+
+	guard(mutex)(&alps_mutex);
+
+	if (!priv->dev3) {
+		error = alps_do_register_bare_ps2_mouse(priv);
+		if (error) {
+			/*
+			 * Save the error code so that we can detect that we
+			 * already tried to create the device.
+			 */
+			priv->dev3 = ERR_PTR(error);
+		}
+	}
 }
 
 static void alps_report_bare_ps2_packet(struct psmouse *psmouse,

Signature · 5 lines

2.46.0.295.g3b9ea8a38a-goog


-- 
Dmitry

Hello, I'm not familiar with new guards and their usage. But if this is a preferred way for handling mutexes then go ahead.

I just looked at the code and I do not see any obvious error neither in old nor in new version.

Hi Pali,

Quoted 4 lines · Pali Rohár

Hello, I'm not familiar with new guards and their usage. But if this is a preferred way for handling mutexes then go ahead.

Quoted 2 lines

I just looked at the code and I do not see any obvious error neither in old nor in new version.

Is this a Reviewed-by or Acked-by? If neither that is fine too, just want to make sure.

Thanks.

Signature · 1 line

Dmitry

Quoted 13 lines · On Thursday 29 August 2024 10:57:41 Dmitry Torokhov wrote:

Hi Pali,

Quoted 6 lines · Pali Rohár

Hello, I'm not familiar with new guards and their usage. But if this is a preferred way for handling mutexes then go ahead.

I just looked at the code and I do not see any obvious error neither in old nor in new version.

Is this a Reviewed-by or Acked-by? If neither that is fine too, just want to make sure.

Quoted 4 lines

Thanks.

Signature · 1 line

Dmitry

Hello, I have looked at it again, and you can add my:

Acked-by Pali Rohár <[email protected]>

This makes the code …