[RFC PATCH 15/30] staging: comedi: dt9812: move the sempaphore used by the comedi_driver

[H Hartley Sweeten]

The semaphore in the struct slot_dt9812 is used by the comedi_driver
when reading and writing to the usb device. It has no real association
with the 'slot'. The 'slot' is protected with a static semaphore in
the driver.

Move the semaphore into the comedi_device private data and initialize
it after the private data is allocated.

Signed-off-by: H Hartley Sweeten <hswee...@visionengravers.com>
Cc: Ian Abbott <abbo...@mev.co.uk>
Cc: Greg Kroah-Hartman <gre...@linuxfonudation.org>
---
 drivers/staging/comedi/drivers/dt9812.c | 34 ++++++++++++++-------------------
 1 file changed, 14 insertions(+), 20 deletions(-)

diff --git a/drivers/staging/comedi/drivers/dt9812.c 
b/drivers/staging/comedi/drivers/dt9812.c
index 94ab0c5..7c26866 100644
--- a/drivers/staging/comedi/drivers/dt9812.c
+++ b/drivers/staging/comedi/drivers/dt9812.c
@@ -280,11 +280,11 @@ struct usb_dt9812 {
 };
 
 struct dt9812_private {
+       struct semaphore sem;
        struct slot_dt9812 *slot;
 };
 
 struct slot_dt9812 {
-       struct semaphore mutex;
        struct usb_dt9812 *usb;
        struct dt9812_private *devpriv;
 };
@@ -391,7 +391,7 @@ static int dt9812_digital_in(struct comedi_device *dev, u8 
*bits)
        struct slot_dt9812 *slot = devpriv->slot;
        int ret = -ENODEV;
 
-       down(&slot->mutex);
+       down(&devpriv->sem);
        if (slot->usb) {
                u8 reg[2] = { F020_SFR_P3, F020_SFR_P1 };
                u8 value[2];
@@ -406,7 +406,7 @@ static int dt9812_digital_in(struct comedi_device *dev, u8 
*bits)
                        *bits = (value[0] & 0x7f) | ((value[1] & 0x08) << 4);
                }
        }
-       up(&slot->mutex);
+       up(&devpriv->sem);
 
        return ret;
 }
@@ -417,7 +417,7 @@ static int dt9812_digital_out(struct comedi_device *dev, u8 
bits)
        struct slot_dt9812 *slot = devpriv->slot;
        int ret = -ENODEV;
 
-       down(&slot->mutex);
+       down(&devpriv->sem);
        if (slot->usb) {
                u8 reg[1] = { F020_SFR_P2 };
                u8 value[1] = { bits };
@@ -425,7 +425,7 @@ static int dt9812_digital_out(struct comedi_device *dev, u8 
bits)
                ret = dt9812_write_multiple_registers(slot->usb, 1, reg, value);
                slot->usb->digital_out_shadow = bits;
        }
-       up(&slot->mutex);
+       up(&devpriv->sem);
 
        return ret;
 }
@@ -436,12 +436,12 @@ static int dt9812_digital_out_shadow(struct comedi_device 
*dev, u8 *bits)
        struct slot_dt9812 *slot = devpriv->slot;
        int ret = -ENODEV;
 
-       down(&slot->mutex);
+       down(&devpriv->sem);
        if (slot->usb) {
                *bits = slot->usb->digital_out_shadow;
                ret = 0;
        }
-       up(&slot->mutex);
+       up(&devpriv->sem);
 
        return ret;
 }
@@ -532,7 +532,7 @@ static int dt9812_analog_in(struct comedi_device *dev,
        u8 val[3];
        int ret = -ENODEV;
 
-       down(&slot->mutex);
+       down(&devpriv->sem);
        if (!slot->usb)
                goto exit;
 
@@ -583,7 +583,7 @@ static int dt9812_analog_in(struct comedi_device *dev,
        }
 
 exit:
-       up(&slot->mutex);
+       up(&devpriv->sem);
 
        return ret;
 }
@@ -595,12 +595,12 @@ static int dt9812_analog_out_shadow(struct comedi_device 
*dev,
        struct slot_dt9812 *slot = devpriv->slot;
        int ret = -ENODEV;
 
-       down(&slot->mutex);
+       down(&devpriv->sem);
        if (slot->usb) {
                *value = slot->usb->analog_out_shadow[channel];
                ret = 0;
        }
-       up(&slot->mutex);
+       up(&devpriv->sem);
 
        return ret;
 }
@@ -611,7 +611,7 @@ static int dt9812_analog_out(struct comedi_device *dev, int 
channel, u16 value)
        struct slot_dt9812 *slot = devpriv->slot;
        int ret = -ENODEV;
 
-       down(&slot->mutex);
+       down(&devpriv->sem);
        if (slot->usb) {
                struct dt9812_rmw_byte rmw[3];
 
@@ -655,7 +655,7 @@ static int dt9812_analog_out(struct comedi_device *dev, int 
channel, u16 value)
                ret = dt9812_rmw_multiple_registers(slot->usb, 3, rmw);
                slot->usb->analog_out_shadow[channel] = value;
        }
-       up(&slot->mutex);
+       up(&devpriv->sem);
 
        return ret;
 }
@@ -751,6 +751,7 @@ static int dt9812_attach(struct comedi_device *dev, struct 
comedi_devconfig *it)
        if (!devpriv)
                return -ENOMEM;
        dev->private = devpriv;
+       sema_init(&devpriv->sem, 1);
 
        down(&dt9812_mutex);
 
@@ -769,11 +770,9 @@ static int dt9812_attach(struct comedi_device *dev, struct 
comedi_devconfig *it)
                return -ENODEV;
        }
 
-       down(&slot->mutex);
        slot->devpriv = devpriv;
        devpriv->slot = slot;
        range_2_5 = (slot->usb->device == DT9812_DEVID_DT9812_2PT5);
-       up(&slot->mutex);
 
        up(&dt9812_mutex);
 
@@ -871,10 +870,8 @@ static int dt9812_probe(struct usb_interface *interface,
                goto error;
        }
 
-       down(&slot->mutex);
        slot->usb = dev;
        dev->slot = slot;
-       up(&slot->mutex);
 
        up(&dt9812_mutex);
 
@@ -1001,9 +998,7 @@ static void dt9812_disconnect(struct usb_interface 
*interface)
        down(&dt9812_mutex);
        dev = usb_get_intfdata(interface);
        if (dev->slot) {
-               down(&dev->slot->mutex);
                dev->slot->usb = NULL;
-               up(&dev->slot->mutex);
                dev->slot = NULL;
        }
        usb_set_intfdata(interface, NULL);
@@ -1034,7 +1029,6 @@ static int __init usb_dt9812_init(void)
 
        /* Initialize all driver slots */
        for (i = 0; i < DT9812_NUM_SLOTS; i++) {
-               sema_init(&dt9812[i].mutex, 1);
                dt9812[i].usb = NULL;
                dt9812[i].devpriv = NULL;
        }
-- 
1.8.1.4

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