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

From: Dmitry Torokhov
Date: Sun Aug 25 2024 - 01:26:18 EST


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@xxxxxxxxx>
---
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