[PATCH] staging: comedi: usbduxsigma: Improve unlocking of a mutex in three functions

[SF Markus Elfring]

From: Markus Elfring <elfr...@users.sourceforge.net>
Date: Thu, 2 Nov 2017 21:16:50 +0100

* Add a jump target so that a call of the function "mutex_unlock" is stored
  only twice in these function implementations.

* Replace seven calls by goto statements.

This issue was detected by using the Coccinelle software.

Signed-off-by: Markus Elfring <elfr...@users.sourceforge.net>
---
 drivers/staging/comedi/drivers/usbduxsigma.c | 48 +++++++++++++++-------------
 1 file changed, 26 insertions(+), 22 deletions(-)

diff --git a/drivers/staging/comedi/drivers/usbduxsigma.c 
b/drivers/staging/comedi/drivers/usbduxsigma.c
index 456e9f13becb..7e8284ed265a 100644
--- a/drivers/staging/comedi/drivers/usbduxsigma.c
+++ b/drivers/staging/comedi/drivers/usbduxsigma.c
@@ -672,10 +672,8 @@ static int usbduxsigma_ai_cmd(struct comedi_device *dev,
        devpriv->dux_commands[8] = sysred;
 
        ret = usbbuxsigma_send_cmd(dev, USBBUXSIGMA_AD_CMD);
-       if (ret < 0) {
-               mutex_unlock(&devpriv->mut);
-               return ret;
-       }
+       if (ret < 0)
+               goto unlock;
 
        devpriv->ai_counter = devpriv->ai_timer;
 
@@ -686,8 +684,7 @@ static int usbduxsigma_ai_cmd(struct comedi_device *dev,
                                              devpriv->n_ai_urbs, 1);
                if (ret < 0) {
                        devpriv->ai_cmd_running = 0;
-                       mutex_unlock(&devpriv->mut);
-                       return ret;
+                       goto unlock;
                }
                s->async->inttrig = NULL;
        } else {        /* TRIG_INT */
@@ -697,6 +694,10 @@ static int usbduxsigma_ai_cmd(struct comedi_device *dev,
        mutex_unlock(&devpriv->mut);
 
        return 0;
+
+unlock:
+       mutex_unlock(&devpriv->mut);
+       return ret;
 }
 
 static int usbduxsigma_ai_insn_read(struct comedi_device *dev,
@@ -714,8 +715,8 @@ static int usbduxsigma_ai_insn_read(struct comedi_device 
*dev,
 
        mutex_lock(&devpriv->mut);
        if (devpriv->ai_cmd_running) {
-               mutex_unlock(&devpriv->mut);
-               return -EBUSY;
+               ret = -EBUSY;
+               goto unlock;
        }
 
        create_adc_command(chan, &muxsg0, &muxsg1);
@@ -730,19 +731,15 @@ static int usbduxsigma_ai_insn_read(struct comedi_device 
*dev,
 
        /* adc commands */
        ret = usbbuxsigma_send_cmd(dev, USBDUXSIGMA_SINGLE_AD_CMD);
-       if (ret < 0) {
-               mutex_unlock(&devpriv->mut);
-               return ret;
-       }
+       if (ret < 0)
+               goto unlock;
 
        for (i = 0; i < insn->n; i++) {
                u32 val;
 
                ret = usbduxsigma_receive_cmd(dev, USBDUXSIGMA_SINGLE_AD_CMD);
-               if (ret < 0) {
-                       mutex_unlock(&devpriv->mut);
-                       return ret;
-               }
+               if (ret < 0)
+                       goto unlock;
 
                /* 32 bits big endian from the A/D converter */
                val = be32_to_cpu(get_unaligned((__be32
@@ -753,6 +750,10 @@ static int usbduxsigma_ai_insn_read(struct comedi_device 
*dev,
        mutex_unlock(&devpriv->mut);
 
        return insn->n;
+
+unlock:
+       mutex_unlock(&devpriv->mut);
+       return ret;
 }
 
 static int usbduxsigma_ao_insn_read(struct comedi_device *dev,
@@ -782,8 +783,8 @@ static int usbduxsigma_ao_insn_write(struct comedi_device 
*dev,
 
        mutex_lock(&devpriv->mut);
        if (devpriv->ao_cmd_running) {
-               mutex_unlock(&devpriv->mut);
-               return -EBUSY;
+               ret = -EBUSY;
+               goto unlock;
        }
 
        for (i = 0; i < insn->n; i++) {
@@ -791,15 +792,18 @@ static int usbduxsigma_ao_insn_write(struct comedi_device 
*dev,
                devpriv->dux_commands[2] = data[i];     /* value */
                devpriv->dux_commands[3] = chan;        /* channel number */
                ret = usbbuxsigma_send_cmd(dev, USBDUXSIGMA_DA_CMD);
-               if (ret < 0) {
-                       mutex_unlock(&devpriv->mut);
-                       return ret;
-               }
+               if (ret < 0)
+                       goto unlock;
+
                s->readback[chan] = data[i];
        }
        mutex_unlock(&devpriv->mut);
 
        return insn->n;
+
+unlock:
+       mutex_unlock(&devpriv->mut);
+       return ret;
 }
 
 static int usbduxsigma_ao_inttrig(struct comedi_device *dev,
-- 
2.15.0

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