Re: [PATCH] staging: dgnc: replace DGNC_VERIFY_BOARD macro

[Greg KH]

On Mon, Oct 17, 2016 at 11:46:36PM +0200, Fernando Apesteguía wrote:
> On Mon, Oct 17, 2016 at 10:29 AM, Greg KH  wrote:
> > On Fri, Oct 14, 2016 at 07:22:57PM +0200, Fernando Apesteguia wrote:
> >> The patch replaces the macro with a function (dgnc_get_board) and
> >> substitutes the macro statement with a call to that function and a
> >> comparison on the returned value.
> >>
> >> This removes a checkpatch warning.
> >>
> >> Signed-off-by: Fernando Apesteguia 
> >> ---
> >>  drivers/staging/dgnc/dgnc_sysfs.c | 74 
> >> +++
> >>  1 file changed, 51 insertions(+), 23 deletions(-)
> >>
> >> diff --git a/drivers/staging/dgnc/dgnc_sysfs.c 
> >> b/drivers/staging/dgnc/dgnc_sysfs.c
> >> index 290bf6e..3ea23a9 100644
> >> --- a/drivers/staging/dgnc/dgnc_sysfs.c
> >> +++ b/drivers/staging/dgnc/dgnc_sysfs.c
> >> @@ -90,17 +90,21 @@ void dgnc_remove_driver_sysfiles(struct pci_driver 
> >> *dgnc_driver)
> >>   driver_remove_file(driverfs, _attr_pollrate);
> >>  }
> >>
> >> -#define DGNC_VERIFY_BOARD(p, bd) \
> >> - do {\
> >> - if (!p) \
> >> - return 0;   \
> >> - \
> >> - bd = dev_get_drvdata(p);\
> >> - if (!bd || bd->magic != DGNC_BOARD_MAGIC)   \
> >> - return 0;   \
> >> - if (bd->state != BOARD_READY)   \
> >> - return 0;   \
> >> - } while (0)
> >> +static struct dgnc_board *dgnc_get_board(struct device *p)
> >> +{
> >> + struct dgnc_board *bd;
> >> +
> >> + if (!p)
> >> + return NULL;
> >> +
> >> + bd = dev_get_drvdata(p);
> >> + if (!bd || bd->magic != DGNC_BOARD_MAGIC)
> >> + return NULL;
> >> + if (bd->state != BOARD_READY)
> >> + return NULL;
> >> +
> >> + return bd;
> >> +}
> >
> > No, this macro should be removed entirely as what it does is pointless
> > in some parts, wrong in others, and not needed at all in the rest :(
> >
> > I've asked others to fix this up properly in the past, but it doesn't
> > seem like anyone wants to do the work...
> >
> 
> I tried to find the discussion the relevant mails in lkml.org but
> couldn't find them. Could  you point me to them so I can have a look?

Last time I mentioned this, it was on the outreachy-kernel mailing list.

Just walk through the code for yourself and see which, if any, of these
things could ever actually cause the function to "fail".  I think you
will find that none of them can ever happen...

The first test is a huge proof that the original author didn't
understand how sysfs or "container_of()" works, given that it is
impossible to ever have happen.

thanks,

greg k-h

Re: [PATCH] staging: dgnc: replace DGNC_VERIFY_BOARD macro

[Greg KH]

On Mon, Oct 17, 2016 at 11:46:36PM +0200, Fernando Apesteguía wrote:
> On Mon, Oct 17, 2016 at 10:29 AM, Greg KH  wrote:
> > On Fri, Oct 14, 2016 at 07:22:57PM +0200, Fernando Apesteguia wrote:
> >> The patch replaces the macro with a function (dgnc_get_board) and
> >> substitutes the macro statement with a call to that function and a
> >> comparison on the returned value.
> >>
> >> This removes a checkpatch warning.
> >>
> >> Signed-off-by: Fernando Apesteguia 
> >> ---
> >>  drivers/staging/dgnc/dgnc_sysfs.c | 74 
> >> +++
> >>  1 file changed, 51 insertions(+), 23 deletions(-)
> >>
> >> diff --git a/drivers/staging/dgnc/dgnc_sysfs.c 
> >> b/drivers/staging/dgnc/dgnc_sysfs.c
> >> index 290bf6e..3ea23a9 100644
> >> --- a/drivers/staging/dgnc/dgnc_sysfs.c
> >> +++ b/drivers/staging/dgnc/dgnc_sysfs.c
> >> @@ -90,17 +90,21 @@ void dgnc_remove_driver_sysfiles(struct pci_driver 
> >> *dgnc_driver)
> >>   driver_remove_file(driverfs, _attr_pollrate);
> >>  }
> >>
> >> -#define DGNC_VERIFY_BOARD(p, bd) \
> >> - do {\
> >> - if (!p) \
> >> - return 0;   \
> >> - \
> >> - bd = dev_get_drvdata(p);\
> >> - if (!bd || bd->magic != DGNC_BOARD_MAGIC)   \
> >> - return 0;   \
> >> - if (bd->state != BOARD_READY)   \
> >> - return 0;   \
> >> - } while (0)
> >> +static struct dgnc_board *dgnc_get_board(struct device *p)
> >> +{
> >> + struct dgnc_board *bd;
> >> +
> >> + if (!p)
> >> + return NULL;
> >> +
> >> + bd = dev_get_drvdata(p);
> >> + if (!bd || bd->magic != DGNC_BOARD_MAGIC)
> >> + return NULL;
> >> + if (bd->state != BOARD_READY)
> >> + return NULL;
> >> +
> >> + return bd;
> >> +}
> >
> > No, this macro should be removed entirely as what it does is pointless
> > in some parts, wrong in others, and not needed at all in the rest :(
> >
> > I've asked others to fix this up properly in the past, but it doesn't
> > seem like anyone wants to do the work...
> >
> 
> I tried to find the discussion the relevant mails in lkml.org but
> couldn't find them. Could  you point me to them so I can have a look?

Last time I mentioned this, it was on the outreachy-kernel mailing list.

Just walk through the code for yourself and see which, if any, of these
things could ever actually cause the function to "fail".  I think you
will find that none of them can ever happen...

The first test is a huge proof that the original author didn't
understand how sysfs or "container_of()" works, given that it is
impossible to ever have happen.

thanks,

greg k-h

Re: [PATCH] staging: dgnc: replace DGNC_VERIFY_BOARD macro

[Fernando Apesteguía]

On Mon, Oct 17, 2016 at 10:29 AM, Greg KH  wrote:
> On Fri, Oct 14, 2016 at 07:22:57PM +0200, Fernando Apesteguia wrote:
>> The patch replaces the macro with a function (dgnc_get_board) and
>> substitutes the macro statement with a call to that function and a
>> comparison on the returned value.
>>
>> This removes a checkpatch warning.
>>
>> Signed-off-by: Fernando Apesteguia 
>> ---
>>  drivers/staging/dgnc/dgnc_sysfs.c | 74 
>> +++
>>  1 file changed, 51 insertions(+), 23 deletions(-)
>>
>> diff --git a/drivers/staging/dgnc/dgnc_sysfs.c 
>> b/drivers/staging/dgnc/dgnc_sysfs.c
>> index 290bf6e..3ea23a9 100644
>> --- a/drivers/staging/dgnc/dgnc_sysfs.c
>> +++ b/drivers/staging/dgnc/dgnc_sysfs.c
>> @@ -90,17 +90,21 @@ void dgnc_remove_driver_sysfiles(struct pci_driver 
>> *dgnc_driver)
>>   driver_remove_file(driverfs, _attr_pollrate);
>>  }
>>
>> -#define DGNC_VERIFY_BOARD(p, bd) \
>> - do {\
>> - if (!p) \
>> - return 0;   \
>> - \
>> - bd = dev_get_drvdata(p);\
>> - if (!bd || bd->magic != DGNC_BOARD_MAGIC)   \
>> - return 0;   \
>> - if (bd->state != BOARD_READY)   \
>> - return 0;   \
>> - } while (0)
>> +static struct dgnc_board *dgnc_get_board(struct device *p)
>> +{
>> + struct dgnc_board *bd;
>> +
>> + if (!p)
>> + return NULL;
>> +
>> + bd = dev_get_drvdata(p);
>> + if (!bd || bd->magic != DGNC_BOARD_MAGIC)
>> + return NULL;
>> + if (bd->state != BOARD_READY)
>> + return NULL;
>> +
>> + return bd;
>> +}
>
> No, this macro should be removed entirely as what it does is pointless
> in some parts, wrong in others, and not needed at all in the rest :(
>
> I've asked others to fix this up properly in the past, but it doesn't
> seem like anyone wants to do the work...
>

I tried to find the discussion the relevant mails in lkml.org but
couldn't find them. Could  you point me to them so I can have a look?

Thanks.

> I don't want to take this patch as it will hide the real issues here.
>
> thanks,
>
> greg k-h

Re: [PATCH] staging: dgnc: replace DGNC_VERIFY_BOARD macro

[Fernando Apesteguía]

On Mon, Oct 17, 2016 at 10:29 AM, Greg KH  wrote:
> On Fri, Oct 14, 2016 at 07:22:57PM +0200, Fernando Apesteguia wrote:
>> The patch replaces the macro with a function (dgnc_get_board) and
>> substitutes the macro statement with a call to that function and a
>> comparison on the returned value.
>>
>> This removes a checkpatch warning.
>>
>> Signed-off-by: Fernando Apesteguia 
>> ---
>>  drivers/staging/dgnc/dgnc_sysfs.c | 74 
>> +++
>>  1 file changed, 51 insertions(+), 23 deletions(-)
>>
>> diff --git a/drivers/staging/dgnc/dgnc_sysfs.c 
>> b/drivers/staging/dgnc/dgnc_sysfs.c
>> index 290bf6e..3ea23a9 100644
>> --- a/drivers/staging/dgnc/dgnc_sysfs.c
>> +++ b/drivers/staging/dgnc/dgnc_sysfs.c
>> @@ -90,17 +90,21 @@ void dgnc_remove_driver_sysfiles(struct pci_driver 
>> *dgnc_driver)
>>   driver_remove_file(driverfs, _attr_pollrate);
>>  }
>>
>> -#define DGNC_VERIFY_BOARD(p, bd) \
>> - do {\
>> - if (!p) \
>> - return 0;   \
>> - \
>> - bd = dev_get_drvdata(p);\
>> - if (!bd || bd->magic != DGNC_BOARD_MAGIC)   \
>> - return 0;   \
>> - if (bd->state != BOARD_READY)   \
>> - return 0;   \
>> - } while (0)
>> +static struct dgnc_board *dgnc_get_board(struct device *p)
>> +{
>> + struct dgnc_board *bd;
>> +
>> + if (!p)
>> + return NULL;
>> +
>> + bd = dev_get_drvdata(p);
>> + if (!bd || bd->magic != DGNC_BOARD_MAGIC)
>> + return NULL;
>> + if (bd->state != BOARD_READY)
>> + return NULL;
>> +
>> + return bd;
>> +}
>
> No, this macro should be removed entirely as what it does is pointless
> in some parts, wrong in others, and not needed at all in the rest :(
>
> I've asked others to fix this up properly in the past, but it doesn't
> seem like anyone wants to do the work...
>

I tried to find the discussion the relevant mails in lkml.org but
couldn't find them. Could  you point me to them so I can have a look?

Thanks.

> I don't want to take this patch as it will hide the real issues here.
>
> thanks,
>
> greg k-h

Re: [PATCH] staging: dgnc: replace DGNC_VERIFY_BOARD macro

[Greg KH]

On Fri, Oct 14, 2016 at 07:22:57PM +0200, Fernando Apesteguia wrote:
> The patch replaces the macro with a function (dgnc_get_board) and
> substitutes the macro statement with a call to that function and a
> comparison on the returned value.
> 
> This removes a checkpatch warning.
> 
> Signed-off-by: Fernando Apesteguia 
> ---
>  drivers/staging/dgnc/dgnc_sysfs.c | 74 
> +++
>  1 file changed, 51 insertions(+), 23 deletions(-)
> 
> diff --git a/drivers/staging/dgnc/dgnc_sysfs.c 
> b/drivers/staging/dgnc/dgnc_sysfs.c
> index 290bf6e..3ea23a9 100644
> --- a/drivers/staging/dgnc/dgnc_sysfs.c
> +++ b/drivers/staging/dgnc/dgnc_sysfs.c
> @@ -90,17 +90,21 @@ void dgnc_remove_driver_sysfiles(struct pci_driver 
> *dgnc_driver)
>   driver_remove_file(driverfs, _attr_pollrate);
>  }
>  
> -#define DGNC_VERIFY_BOARD(p, bd) \
> - do {\
> - if (!p) \
> - return 0;   \
> - \
> - bd = dev_get_drvdata(p);\
> - if (!bd || bd->magic != DGNC_BOARD_MAGIC)   \
> - return 0;   \
> - if (bd->state != BOARD_READY)   \
> - return 0;   \
> - } while (0)
> +static struct dgnc_board *dgnc_get_board(struct device *p)
> +{
> + struct dgnc_board *bd;
> +
> + if (!p)
> + return NULL;
> +
> + bd = dev_get_drvdata(p);
> + if (!bd || bd->magic != DGNC_BOARD_MAGIC)
> + return NULL;
> + if (bd->state != BOARD_READY)
> + return NULL;
> +
> + return bd;
> +}

No, this macro should be removed entirely as what it does is pointless
in some parts, wrong in others, and not needed at all in the rest :(

I've asked others to fix this up properly in the past, but it doesn't
seem like anyone wants to do the work...

I don't want to take this patch as it will hide the real issues here.

thanks,

greg k-h

Re: [PATCH] staging: dgnc: replace DGNC_VERIFY_BOARD macro

[Greg KH]

On Fri, Oct 14, 2016 at 07:22:57PM +0200, Fernando Apesteguia wrote:
> The patch replaces the macro with a function (dgnc_get_board) and
> substitutes the macro statement with a call to that function and a
> comparison on the returned value.
> 
> This removes a checkpatch warning.
> 
> Signed-off-by: Fernando Apesteguia 
> ---
>  drivers/staging/dgnc/dgnc_sysfs.c | 74 
> +++
>  1 file changed, 51 insertions(+), 23 deletions(-)
> 
> diff --git a/drivers/staging/dgnc/dgnc_sysfs.c 
> b/drivers/staging/dgnc/dgnc_sysfs.c
> index 290bf6e..3ea23a9 100644
> --- a/drivers/staging/dgnc/dgnc_sysfs.c
> +++ b/drivers/staging/dgnc/dgnc_sysfs.c
> @@ -90,17 +90,21 @@ void dgnc_remove_driver_sysfiles(struct pci_driver 
> *dgnc_driver)
>   driver_remove_file(driverfs, _attr_pollrate);
>  }
>  
> -#define DGNC_VERIFY_BOARD(p, bd) \
> - do {\
> - if (!p) \
> - return 0;   \
> - \
> - bd = dev_get_drvdata(p);\
> - if (!bd || bd->magic != DGNC_BOARD_MAGIC)   \
> - return 0;   \
> - if (bd->state != BOARD_READY)   \
> - return 0;   \
> - } while (0)
> +static struct dgnc_board *dgnc_get_board(struct device *p)
> +{
> + struct dgnc_board *bd;
> +
> + if (!p)
> + return NULL;
> +
> + bd = dev_get_drvdata(p);
> + if (!bd || bd->magic != DGNC_BOARD_MAGIC)
> + return NULL;
> + if (bd->state != BOARD_READY)
> + return NULL;
> +
> + return bd;
> +}

No, this macro should be removed entirely as what it does is pointless
in some parts, wrong in others, and not needed at all in the rest :(

I've asked others to fix this up properly in the past, but it doesn't
seem like anyone wants to do the work...

I don't want to take this patch as it will hide the real issues here.

thanks,

greg k-h

[PATCH] staging: dgnc: replace DGNC_VERIFY_BOARD macro

[Fernando Apesteguia]

The patch replaces the macro with a function (dgnc_get_board) and
substitutes the macro statement with a call to that function and a
comparison on the returned value.

This removes a checkpatch warning.

Signed-off-by: Fernando Apesteguia 
---
 drivers/staging/dgnc/dgnc_sysfs.c | 74 +++
 1 file changed, 51 insertions(+), 23 deletions(-)

diff --git a/drivers/staging/dgnc/dgnc_sysfs.c 
b/drivers/staging/dgnc/dgnc_sysfs.c
index 290bf6e..3ea23a9 100644
--- a/drivers/staging/dgnc/dgnc_sysfs.c
+++ b/drivers/staging/dgnc/dgnc_sysfs.c
@@ -90,17 +90,21 @@ void dgnc_remove_driver_sysfiles(struct pci_driver 
*dgnc_driver)
driver_remove_file(driverfs, _attr_pollrate);
 }
 
-#define DGNC_VERIFY_BOARD(p, bd)   \
-   do {\
-   if (!p) \
-   return 0;   \
-   \
-   bd = dev_get_drvdata(p);\
-   if (!bd || bd->magic != DGNC_BOARD_MAGIC)   \
-   return 0;   \
-   if (bd->state != BOARD_READY)   \
-   return 0;   \
-   } while (0)
+static struct dgnc_board *dgnc_get_board(struct device *p)
+{
+   struct dgnc_board *bd;
+
+   if (!p)
+   return NULL;
+
+   bd = dev_get_drvdata(p);
+   if (!bd || bd->magic != DGNC_BOARD_MAGIC)
+   return NULL;
+   if (bd->state != BOARD_READY)
+   return NULL;
+
+   return bd;
+}
 
 static ssize_t vpd_show(struct device *p, struct device_attribute *attr,
char *buf)
@@ -109,7 +113,9 @@ static ssize_t vpd_show(struct device *p, struct 
device_attribute *attr,
int count = 0;
int i = 0;
 
-   DGNC_VERIFY_BOARD(p, bd);
+   bd = dgnc_get_board(p);
+   if (!bd)
+   return 0;
 
count += sprintf(buf + count,
"\n  0  1  2  3  4  5  6  7  8  9  A  B  C  D  E  F");
@@ -130,7 +136,9 @@ static ssize_t serial_number_show(struct device *p,
struct dgnc_board *bd;
int count = 0;
 
-   DGNC_VERIFY_BOARD(p, bd);
+   bd = dgnc_get_board(p);
+   if (!bd)
+   return 0;
 
if (bd->serial_num[0] == '\0')
count += sprintf(buf + count, "\n");
@@ -148,7 +156,9 @@ static ssize_t ports_state_show(struct device *p,
int count = 0;
int i = 0;
 
-   DGNC_VERIFY_BOARD(p, bd);
+   bd = dgnc_get_board(p);
+   if (!bd)
+   return 0;
 
for (i = 0; i < bd->nasync; i++) {
count += snprintf(buf + count, PAGE_SIZE - count,
@@ -166,7 +176,9 @@ static ssize_t ports_baud_show(struct device *p,
int count = 0;
int i = 0;
 
-   DGNC_VERIFY_BOARD(p, bd);
+   bd = dgnc_get_board(p);
+   if (!bd)
+   return 0;
 
for (i = 0; i < bd->nasync; i++) {
count +=  snprintf(buf + count, PAGE_SIZE - count,
@@ -184,7 +196,9 @@ static ssize_t ports_msignals_show(struct device *p,
int count = 0;
int i = 0;
 
-   DGNC_VERIFY_BOARD(p, bd);
+   bd = dgnc_get_board(p);
+   if (!bd)
+   return 0;
 
for (i = 0; i < bd->nasync; i++) {
struct channel_t *ch = bd->channels[i];
@@ -215,7 +229,9 @@ static ssize_t ports_iflag_show(struct device *p,
int count = 0;
int i = 0;
 
-   DGNC_VERIFY_BOARD(p, bd);
+   bd = dgnc_get_board(p);
+   if (!bd)
+   return 0;
 
for (i = 0; i < bd->nasync; i++) {
count += snprintf(buf + count, PAGE_SIZE - count, "%d %x\n",
@@ -233,7 +249,9 @@ static ssize_t ports_cflag_show(struct device *p,
int count = 0;
int i = 0;
 
-   DGNC_VERIFY_BOARD(p, bd);
+   bd = dgnc_get_board(p);
+   if (!bd)
+   return 0;
 
for (i = 0; i < bd->nasync; i++) {
count += snprintf(buf + count, PAGE_SIZE - count, "%d %x\n",
@@ -251,7 +269,9 @@ static ssize_t ports_oflag_show(struct device *p,
int count = 0;
int i = 0;
 
-   DGNC_VERIFY_BOARD(p, bd);
+   bd = dgnc_get_board(p);
+   if (!bd)
+   return 0;
 
for (i = 0; i < bd->nasync; i++) {
count += snprintf(buf + count, PAGE_SIZE - count, "%d %x\n",
@@ -269,7 +289,9 @@ static ssize_t ports_lflag_show(struct device *p,
int count = 0;
int i = 0;
 
-   DGNC_VERIFY_BOARD(p, bd);
+   bd = dgnc_get_board(p);
+   if (!bd)
+   return 0;
 
for (i = 0; i < bd->nasync; i++) {
count += snprintf(buf + count, PAGE_SIZE - count, "%d %x\n",
@@ -287,7 +309,9 @@ static ssize_t 

[PATCH] staging: dgnc: replace DGNC_VERIFY_BOARD macro

[Fernando Apesteguia]

The patch replaces the macro with a function (dgnc_get_board) and
substitutes the macro statement with a call to that function and a
comparison on the returned value.

This removes a checkpatch warning.

Signed-off-by: Fernando Apesteguia 
---
 drivers/staging/dgnc/dgnc_sysfs.c | 74 +++
 1 file changed, 51 insertions(+), 23 deletions(-)

diff --git a/drivers/staging/dgnc/dgnc_sysfs.c 
b/drivers/staging/dgnc/dgnc_sysfs.c
index 290bf6e..3ea23a9 100644
--- a/drivers/staging/dgnc/dgnc_sysfs.c
+++ b/drivers/staging/dgnc/dgnc_sysfs.c
@@ -90,17 +90,21 @@ void dgnc_remove_driver_sysfiles(struct pci_driver 
*dgnc_driver)
driver_remove_file(driverfs, _attr_pollrate);
 }
 
-#define DGNC_VERIFY_BOARD(p, bd)   \
-   do {\
-   if (!p) \
-   return 0;   \
-   \
-   bd = dev_get_drvdata(p);\
-   if (!bd || bd->magic != DGNC_BOARD_MAGIC)   \
-   return 0;   \
-   if (bd->state != BOARD_READY)   \
-   return 0;   \
-   } while (0)
+static struct dgnc_board *dgnc_get_board(struct device *p)
+{
+   struct dgnc_board *bd;
+
+   if (!p)
+   return NULL;
+
+   bd = dev_get_drvdata(p);
+   if (!bd || bd->magic != DGNC_BOARD_MAGIC)
+   return NULL;
+   if (bd->state != BOARD_READY)
+   return NULL;
+
+   return bd;
+}
 
 static ssize_t vpd_show(struct device *p, struct device_attribute *attr,
char *buf)
@@ -109,7 +113,9 @@ static ssize_t vpd_show(struct device *p, struct 
device_attribute *attr,
int count = 0;
int i = 0;
 
-   DGNC_VERIFY_BOARD(p, bd);
+   bd = dgnc_get_board(p);
+   if (!bd)
+   return 0;
 
count += sprintf(buf + count,
"\n  0  1  2  3  4  5  6  7  8  9  A  B  C  D  E  F");
@@ -130,7 +136,9 @@ static ssize_t serial_number_show(struct device *p,
struct dgnc_board *bd;
int count = 0;
 
-   DGNC_VERIFY_BOARD(p, bd);
+   bd = dgnc_get_board(p);
+   if (!bd)
+   return 0;
 
if (bd->serial_num[0] == '\0')
count += sprintf(buf + count, "\n");
@@ -148,7 +156,9 @@ static ssize_t ports_state_show(struct device *p,
int count = 0;
int i = 0;
 
-   DGNC_VERIFY_BOARD(p, bd);
+   bd = dgnc_get_board(p);
+   if (!bd)
+   return 0;
 
for (i = 0; i < bd->nasync; i++) {
count += snprintf(buf + count, PAGE_SIZE - count,
@@ -166,7 +176,9 @@ static ssize_t ports_baud_show(struct device *p,
int count = 0;
int i = 0;
 
-   DGNC_VERIFY_BOARD(p, bd);
+   bd = dgnc_get_board(p);
+   if (!bd)
+   return 0;
 
for (i = 0; i < bd->nasync; i++) {
count +=  snprintf(buf + count, PAGE_SIZE - count,
@@ -184,7 +196,9 @@ static ssize_t ports_msignals_show(struct device *p,
int count = 0;
int i = 0;
 
-   DGNC_VERIFY_BOARD(p, bd);
+   bd = dgnc_get_board(p);
+   if (!bd)
+   return 0;
 
for (i = 0; i < bd->nasync; i++) {
struct channel_t *ch = bd->channels[i];
@@ -215,7 +229,9 @@ static ssize_t ports_iflag_show(struct device *p,
int count = 0;
int i = 0;
 
-   DGNC_VERIFY_BOARD(p, bd);
+   bd = dgnc_get_board(p);
+   if (!bd)
+   return 0;
 
for (i = 0; i < bd->nasync; i++) {
count += snprintf(buf + count, PAGE_SIZE - count, "%d %x\n",
@@ -233,7 +249,9 @@ static ssize_t ports_cflag_show(struct device *p,
int count = 0;
int i = 0;
 
-   DGNC_VERIFY_BOARD(p, bd);
+   bd = dgnc_get_board(p);
+   if (!bd)
+   return 0;
 
for (i = 0; i < bd->nasync; i++) {
count += snprintf(buf + count, PAGE_SIZE - count, "%d %x\n",
@@ -251,7 +269,9 @@ static ssize_t ports_oflag_show(struct device *p,
int count = 0;
int i = 0;
 
-   DGNC_VERIFY_BOARD(p, bd);
+   bd = dgnc_get_board(p);
+   if (!bd)
+   return 0;
 
for (i = 0; i < bd->nasync; i++) {
count += snprintf(buf + count, PAGE_SIZE - count, "%d %x\n",
@@ -269,7 +289,9 @@ static ssize_t ports_lflag_show(struct device *p,
int count = 0;
int i = 0;
 
-   DGNC_VERIFY_BOARD(p, bd);
+   bd = dgnc_get_board(p);
+   if (!bd)
+   return 0;
 
for (i = 0; i < bd->nasync; i++) {
count += snprintf(buf + count, PAGE_SIZE - count, "%d %x\n",
@@ -287,7 +309,9 @@ static ssize_t ports_digi_flag_show(struct device *p,