From:   Armin Wolf <W_Armin@gmx.de>
To:     pali@kernel.org
Cc:     jdelvare@suse.com, linux@roeck-us.net, linux-hwmon@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: [PATCH v2 2/2] hwmon: (dell-smm) Unify i8k_ioctl() and i8k_ioctl_unlocked()
Date:   Sat, 11 Dec 2021 16:54:22 +0100
Message-Id: <20211211155422.16830-3-W_Armin@gmx.de>
In-Reply-To: <20211211155422.16830-1-W_Armin@gmx.de>
References: <20211211155422.16830-1-W_Armin@gmx.de>
MIME-Version: 1.0
Content-Transfer-Encoding: quoted-printable
Precedence: bulk

The only purpose of i8k_ioctl() is to call i8k_ioctl_unlocked()
with i8k_mutex held. Judging from the hwmon code, this mutex
only needs to be held when setting the fan speed/mode, so
the operation of I8K_SET_FAN is guaranteed to be atomic.
Unify both functions and reduce the locking of i8k_mutex
to I8K_SET_FAN.

Tested on a Dell Inspiron 3505.

Signed-off-by: Armin Wolf <W_Armin@gmx.de>
=2D--
 drivers/hwmon/dell-smm-hwmon.c | 28 +++++++++-------------------
 1 file changed, 9 insertions(+), 19 deletions(-)

diff --git a/drivers/hwmon/dell-smm-hwmon.c b/drivers/hwmon/dell-smm-hwmon=
.c
index 186d40938036..d8c6e75bb374 100644
=2D-- a/drivers/hwmon/dell-smm-hwmon.c
+++ b/drivers/hwmon/dell-smm-hwmon.c
@@ -449,12 +449,12 @@ static int i8k_get_power_status(void)
  * Procfs interface
  */

-static int
-i8k_ioctl_unlocked(struct file *fp, struct dell_smm_data *data, unsigned =
int cmd, unsigned long arg)
+static long i8k_ioctl(struct file *fp, unsigned int cmd, unsigned long ar=
g)
 {
-	int val =3D 0;
-	int speed, err;
+	struct dell_smm_data *data =3D PDE_DATA(file_inode(fp));
 	int __user *argp =3D (int __user *)arg;
+	int speed, err;
+	int val =3D 0;

 	if (!argp)
 		return -EINVAL;
@@ -516,11 +516,13 @@ i8k_ioctl_unlocked(struct file *fp, struct dell_smm_=
data *data, unsigned int cmd
 		if (copy_from_user(&speed, argp + 1, sizeof(int)))
 			return -EFAULT;

+		mutex_lock(&data->i8k_mutex);
 		err =3D i8k_set_fan(data, val, speed);
 		if (err < 0)
-			return err;
-
-		val =3D i8k_get_fan_status(data, val);
+			val =3D err;
+		else
+			val =3D i8k_get_fan_status(data, val);
+		mutex_unlock(&data->i8k_mutex);
 		break;

 	default:
@@ -536,18 +538,6 @@ i8k_ioctl_unlocked(struct file *fp, struct dell_smm_d=
ata *data, unsigned int cmd
 	return 0;
 }

-static long i8k_ioctl(struct file *fp, unsigned int cmd, unsigned long ar=
g)
-{
-	struct dell_smm_data *data =3D PDE_DATA(file_inode(fp));
-	long ret;
-
-	mutex_lock(&data->i8k_mutex);
-	ret =3D i8k_ioctl_unlocked(fp, data, cmd, arg);
-	mutex_unlock(&data->i8k_mutex);
-
-	return ret;
-}
-
 /*
  * Print the information for /proc/i8k.
  */
=2D-
2.30.2