Staging: comedi: dt9812: Use mutex instead of semaphore

Replace binary semaphore with mutex. Mutex also gives better performance
than semaphore.

Signed-off-by: Ksenija Stanojevic <ksenija.stanojevic@gmail.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/comedi/drivers/dt9812.c b/drivers/staging/comedi/drivers/dt9812.c
index 0a4ee8b75aba348dea2fe5e2528f22228c74536e..3295bb4ac8c4cf5a45606569bbfd940b9ab0da3c 100644 (file)
--- a/drivers/staging/comedi/drivers/dt9812.c
+++ b/drivers/staging/comedi/drivers/dt9812.c
@@ -233,7 +233,7 @@ struct dt9812_usb_cmd {
 };
 
 struct dt9812_private {
-       struct semaphore sem;
+       struct mutex mut;
        struct {
                __u8 addr;
                size_t size;
@@ -335,7 +335,7 @@ static int dt9812_digital_in(struct comedi_device *dev, u8 *bits)
        u8 value[2];
        int ret;
 
-       down(&devpriv->sem);
+       mutex_lock(&devpriv->mut);
        ret = dt9812_read_multiple_registers(dev, 2, reg, value);
        if (ret == 0) {
                /*
@@ -345,7 +345,7 @@ static int dt9812_digital_in(struct comedi_device *dev, u8 *bits)
                 */
                *bits = (value[0] & 0x7f) | ((value[1] & 0x08) << 4);
        }
-       up(&devpriv->sem);
+       mutex_unlock(&devpriv->mut);
 
        return ret;
 }
@@ -357,9 +357,9 @@ static int dt9812_digital_out(struct comedi_device *dev, u8 bits)
        u8 value[1] = { bits };
        int ret;
 
-       down(&devpriv->sem);
+       mutex_lock(&devpriv->mut);
        ret = dt9812_write_multiple_registers(dev, 1, reg, value);
-       up(&devpriv->sem);
+       mutex_unlock(&devpriv->mut);
 
        return ret;
 }
@@ -444,7 +444,7 @@ static int dt9812_analog_in(struct comedi_device *dev,
        u8 val[3];
        int ret;
 
-       down(&devpriv->sem);
+       mutex_lock(&devpriv->mut);
 
        /* 1 select the gain */
        dt9812_configure_gain(dev, &rmw[0], gain);
@@ -493,7 +493,7 @@ static int dt9812_analog_in(struct comedi_device *dev,
        }
 
 exit:
-       up(&devpriv->sem);
+       mutex_unlock(&devpriv->mut);
 
        return ret;
 }
@@ -504,7 +504,7 @@ static int dt9812_analog_out(struct comedi_device *dev, int channel, u16 value)
        struct dt9812_rmw_byte rmw[3];
        int ret;
 
-       down(&devpriv->sem);
+       mutex_lock(&devpriv->mut);
 
        switch (channel) {
        case 0:
@@ -543,7 +543,7 @@ static int dt9812_analog_out(struct comedi_device *dev, int channel, u16 value)
        }
        ret = dt9812_rmw_multiple_registers(dev, 3, rmw);
 
-       up(&devpriv->sem);
+       mutex_unlock(&devpriv->mut);
 
        return ret;
 }
@@ -606,9 +606,9 @@ static int dt9812_ao_insn_read(struct comedi_device *dev,
        struct dt9812_private *devpriv = dev->private;
        int ret;
 
-       down(&devpriv->sem);
+       mutex_lock(&devpriv->mut);
        ret = comedi_readback_insn_read(dev, s, insn, data);
-       up(&devpriv->sem);
+       mutex_unlock(&devpriv->mut);
 
        return ret;
 }
@@ -772,7 +772,7 @@ static int dt9812_auto_attach(struct comedi_device *dev,
        if (!devpriv)
                return -ENOMEM;
 
-       sema_init(&devpriv->sem, 1);
+       mutex_init(&devpriv->mut);
        usb_set_intfdata(intf, devpriv);
 
        ret = dt9812_find_endpoints(dev);
@@ -844,11 +844,11 @@ static void dt9812_detach(struct comedi_device *dev)
        if (!devpriv)
                return;
 
-       down(&devpriv->sem);
+       mutex_lock(&devpriv->mut);
 
        usb_set_intfdata(intf, NULL);
 
-       up(&devpriv->sem);
+       mutex_unlock(&devpriv->mut);
 }
 
 static struct comedi_driver dt9812_driver = {