* [PATCH] staging: comedi: usbduxsigma: Improve unlocking of a mutex in three functions
@ 2017-11-02 20:23 SF Markus Elfring
2017-11-03 14:10 ` Ian Abbott
0 siblings, 1 reply; 2+ messages in thread
From: SF Markus Elfring @ 2017-11-02 20:23 UTC (permalink / raw)
To: devel, Greg Kroah-Hartman, H Hartley Sweeten, Ian Abbott
Cc: LKML, kernel-janitors
From: Markus Elfring <elfring@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 <elfring@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
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] staging: comedi: usbduxsigma: Improve unlocking of a mutex in three functions
2017-11-02 20:23 [PATCH] staging: comedi: usbduxsigma: Improve unlocking of a mutex in three functions SF Markus Elfring
@ 2017-11-03 14:10 ` Ian Abbott
0 siblings, 0 replies; 2+ messages in thread
From: Ian Abbott @ 2017-11-03 14:10 UTC (permalink / raw)
To: SF Markus Elfring, devel, Greg Kroah-Hartman, H Hartley Sweeten
Cc: LKML, kernel-janitors
On 02/11/17 20:23, SF Markus Elfring wrote:
> From: Markus Elfring <elfring@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 <elfring@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;
You could also remove that call by replacing the above three lines with:
ret = 0;
and falling through to the 'unlock:' label. (Actually, you don't even
need the above line, as ret should already be 0 at this point, but I
think it is easier to understand the code if ret is set to 0 explicitly.)
> +
> +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;
Similarly, you could replace the above three lines with:
ret = insn->n;
and fall through to the label.
> +
> +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;
Ditto.
> +
> +unlock:
> + mutex_unlock(&devpriv->mut);
> + return ret;
> }
>
> static int usbduxsigma_ao_inttrig(struct comedi_device *dev,
>
--
-=( Ian Abbott @ MEV Ltd. E-mail: <abbotti@mev.co.uk> )=-
-=( Web: http://www.mev.co.uk/ )=-
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