[PATCH] Input: psmouse-smbus - use guard notation when acquiring mutex

[PATCH] Input: psmouse-smbus - use guard notation when acquiring mutex

[Dmitry Torokhov]

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 <dmitry.torokhov@gmail.com>
---
 drivers/input/mouse/psmouse-smbus.c | 28 ++++++++++------------------
 1 file changed, 10 insertions(+), 18 deletions(-)

diff --git a/drivers/input/mouse/psmouse-smbus.c b/drivers/input/mouse/psmouse-smbus.c
index 2a2459b1b4f2..93420f07b7d0 100644
--- a/drivers/input/mouse/psmouse-smbus.c
+++ b/drivers/input/mouse/psmouse-smbus.c
@@ -35,7 +35,7 @@ static void psmouse_smbus_check_adapter(struct i2c_adapter *adapter)
 	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_HOST_NOTIFY))
 		return;
 
-	mutex_lock(&psmouse_smbus_mutex);
+	guard(mutex)(&psmouse_smbus_mutex);
 
 	list_for_each_entry(smbdev, &psmouse_smbus_list, node) {
 		if (smbdev->dead)
@@ -55,15 +55,13 @@ static void psmouse_smbus_check_adapter(struct i2c_adapter *adapter)
 			    "SMBus candidate adapter appeared, triggering rescan\n");
 		serio_rescan(smbdev->psmouse->ps2dev.serio);
 	}
-
-	mutex_unlock(&psmouse_smbus_mutex);
 }
 
 static void psmouse_smbus_detach_i2c_client(struct i2c_client *client)
 {
 	struct psmouse_smbus_dev *smbdev, *tmp;
 
-	mutex_lock(&psmouse_smbus_mutex);
+	guard(mutex)(&psmouse_smbus_mutex);
 
 	list_for_each_entry_safe(smbdev, tmp, &psmouse_smbus_list, node) {
 		if (smbdev->client != client)
@@ -85,8 +83,6 @@ static void psmouse_smbus_detach_i2c_client(struct i2c_client *client)
 			kfree(smbdev);
 		}
 	}
-
-	mutex_unlock(&psmouse_smbus_mutex);
 }
 
 static int psmouse_smbus_notifier_call(struct notifier_block *nb,
@@ -171,7 +167,7 @@ static void psmouse_smbus_disconnect(struct psmouse *psmouse)
 {
 	struct psmouse_smbus_dev *smbdev = psmouse->private;
 
-	mutex_lock(&psmouse_smbus_mutex);
+	guard(mutex)(&psmouse_smbus_mutex);
 
 	if (smbdev->dead) {
 		list_del(&smbdev->node);
@@ -186,8 +182,6 @@ static void psmouse_smbus_disconnect(struct psmouse *psmouse)
 		psmouse_smbus_schedule_remove(smbdev->client);
 	}
 
-	mutex_unlock(&psmouse_smbus_mutex);
-
 	psmouse->private = NULL;
 }
 
@@ -219,7 +213,7 @@ void psmouse_smbus_cleanup(struct psmouse *psmouse)
 {
 	struct psmouse_smbus_dev *smbdev, *tmp;
 
-	mutex_lock(&psmouse_smbus_mutex);
+	guard(mutex)(&psmouse_smbus_mutex);
 
 	list_for_each_entry_safe(smbdev, tmp, &psmouse_smbus_list, node) {
 		if (psmouse == smbdev->psmouse) {
@@ -227,8 +221,6 @@ void psmouse_smbus_cleanup(struct psmouse *psmouse)
 			kfree(smbdev);
 		}
 	}
-
-	mutex_unlock(&psmouse_smbus_mutex);
 }
 
 int psmouse_smbus_init(struct psmouse *psmouse,
@@ -267,9 +259,9 @@ int psmouse_smbus_init(struct psmouse *psmouse,
 	psmouse->disconnect = psmouse_smbus_disconnect;
 	psmouse->resync_time = 0;
 
-	mutex_lock(&psmouse_smbus_mutex);
-	list_add_tail(&smbdev->node, &psmouse_smbus_list);
-	mutex_unlock(&psmouse_smbus_mutex);
+	scoped_guard(mutex, &psmouse_smbus_mutex) {
+		list_add_tail(&smbdev->node, &psmouse_smbus_list);
+	}
 
 	/* Bind to already existing adapters right away */
 	error = i2c_for_each_dev(smbdev, psmouse_smbus_create_companion);
@@ -293,9 +285,9 @@ int psmouse_smbus_init(struct psmouse *psmouse,
 	smbdev->board.platform_data = NULL;
 
 	if (error < 0 || !leave_breadcrumbs) {
-		mutex_lock(&psmouse_smbus_mutex);
-		list_del(&smbdev->node);
-		mutex_unlock(&psmouse_smbus_mutex);
+		scoped_guard(mutex, &psmouse_smbus_mutex) {
+			list_del(&smbdev->node);
+		}
 
 		kfree(smbdev);
 	}
-- 
2.46.0.295.g3b9ea8a38a-goog


-- 
Dmitry

Re: [PATCH] Input: psmouse-smbus - use guard notation when acquiring mutex

[Markus Elfring]

> This makes the code …

How do you think about to improve such a change description with imperative wordings?
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/submitting-patches.rst?h=v6.11-rc5#n94

Regards,
Markus

Re: [PATCH] Input: psmouse-smbus - use guard notation when acquiring mutex

[Dmitry Torokhov]

On Sat, Aug 24, 2024 at 10:26:03PM -0700, Dmitry Torokhov wrote:
> 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 <dmitry.torokhov@gmail.com>

Applied since there were no objections.

Thanks.

-- 
Dmitry