Re: [PATCH 10/14] [media] ddbridge: remove unreachable code

[Daniel Scheller]

Am Mon, 10 Jul 2017 10:24:00 +0200
schrieb Ralph Metzler :

> Daniel Scheller writes:
>  > From: Daniel Scheller 
>  >   
>  > >From smatch:  
>  > 
>  >   drivers/media/pci/ddbridge/ddbridge-core.c:3490 snr_store()
>  > info: ignoring unreachable code.
>  > 
>  > In fact, the function immediately returns zero, so remove it and
>  > update ddb_attrs_snr[] to not reference it anymore.
>  > 
>  > Cc: Ralph Metzler 
>  > Signed-off-by: Daniel Scheller 
>  > ---
>  >  drivers/media/pci/ddbridge/ddbridge-core.c | 27
>  > --- 1 file changed, 4 insertions(+), 23
>  > deletions(-)
>  > 
>  > diff --git a/drivers/media/pci/ddbridge/ddbridge-core.c
>  > b/drivers/media/pci/ddbridge/ddbridge-core.c index
>  > 8981795b0819..3756b9961fcd 100644 ---
>  > a/drivers/media/pci/ddbridge/ddbridge-core.c +++
>  > b/drivers/media/pci/ddbridge/ddbridge-core.c @@ -3236,25 +3236,6
>  > @@ static ssize_t snr_show(struct device *device, return
>  > sprintf(buf, "%s\n", snr); }
>  >  
>  > -
>  > -static ssize_t snr_store(struct device *device, struct
>  > device_attribute *attr,
>  > -   const char *buf, size_t count)
>  > -{
>  > -  struct ddb *dev = dev_get_drvdata(device);
>  > -  int num = attr->attr.name[3] - 0x30;
>  > -  u8 snr[34] = { 0x01, 0x00 };
>  > -
>  > -  return 0; /* NOE: remove completely? */
>  > -  if (count > 31)
>  > -  return -EINVAL;
>  > -  if (dev->port[num].type >= DDB_TUNER_XO2)
>  > -  return -EINVAL;
>  > -  memcpy(snr + 2, buf, count);
>  > -  i2c_write(>i2c[num].adap, 0x57, snr, 34);
>  > -  i2c_write(>i2c[num].adap, 0x50, snr, 34);
>  > -  return count;
>  > -}
>  > -
>  >  static ssize_t bsnr_show(struct device *device,
>  > struct device_attribute *attr, char *buf)
>  >  {
>  > @@ -3394,10 +3375,10 @@ static struct device_attribute
>  > ddb_attrs_fan[] = { };
>  >  
>  >  static struct device_attribute ddb_attrs_snr[] = {
>  > -  __ATTR(snr0, 0664, snr_show, snr_store),
>  > -  __ATTR(snr1, 0664, snr_show, snr_store),
>  > -  __ATTR(snr2, 0664, snr_show, snr_store),
>  > -  __ATTR(snr3, 0664, snr_show, snr_store),
>  > +  __ATTR_MRO(snr0, snr_show),
>  > +  __ATTR_MRO(snr1, snr_show),
>  > +  __ATTR_MRO(snr2, snr_show),
>  > +  __ATTR_MRO(snr3, snr_show),
>  >  };
>  >  
>  >  static struct device_attribute ddb_attrs_ctemp[] = {
>  > -- 
>  > 2.13.0  
> 
> 
> snr_store was disabled to prevent people from accidentally
> overwriting serial numbers. Maybe it should be a driver/compile
> option.

Is it really neccessary that users - by accident or not - should
be able to tamper with card serials, even "blocked" by compile-time
defines?

Best regards,
Daniel Scheller
-- 
https://github.com/herrnst

[PATCH 10/14] [media] ddbridge: remove unreachable code

[Ralph Metzler]

Daniel Scheller writes:
 > From: Daniel Scheller 
 > 
 > >From smatch:
 > 
 >   drivers/media/pci/ddbridge/ddbridge-core.c:3490 snr_store() info: ignoring 
 > unreachable code.
 > 
 > In fact, the function immediately returns zero, so remove it and update
 > ddb_attrs_snr[] to not reference it anymore.
 > 
 > Cc: Ralph Metzler 
 > Signed-off-by: Daniel Scheller 
 > ---
 >  drivers/media/pci/ddbridge/ddbridge-core.c | 27 ---
 >  1 file changed, 4 insertions(+), 23 deletions(-)
 > 
 > diff --git a/drivers/media/pci/ddbridge/ddbridge-core.c 
 > b/drivers/media/pci/ddbridge/ddbridge-core.c
 > index 8981795b0819..3756b9961fcd 100644
 > --- a/drivers/media/pci/ddbridge/ddbridge-core.c
 > +++ b/drivers/media/pci/ddbridge/ddbridge-core.c
 > @@ -3236,25 +3236,6 @@ static ssize_t snr_show(struct device *device,
 >  return sprintf(buf, "%s\n", snr);
 >  }
 >  
 > -
 > -static ssize_t snr_store(struct device *device, struct device_attribute 
 > *attr,
 > - const char *buf, size_t count)
 > -{
 > -struct ddb *dev = dev_get_drvdata(device);
 > -int num = attr->attr.name[3] - 0x30;
 > -u8 snr[34] = { 0x01, 0x00 };
 > -
 > -return 0; /* NOE: remove completely? */
 > -if (count > 31)
 > -return -EINVAL;
 > -if (dev->port[num].type >= DDB_TUNER_XO2)
 > -return -EINVAL;
 > -memcpy(snr + 2, buf, count);
 > -i2c_write(>i2c[num].adap, 0x57, snr, 34);
 > -i2c_write(>i2c[num].adap, 0x50, snr, 34);
 > -return count;
 > -}
 > -
 >  static ssize_t bsnr_show(struct device *device,
 >   struct device_attribute *attr, char *buf)
 >  {
 > @@ -3394,10 +3375,10 @@ static struct device_attribute ddb_attrs_fan[] = {
 >  };
 >  
 >  static struct device_attribute ddb_attrs_snr[] = {
 > -__ATTR(snr0, 0664, snr_show, snr_store),
 > -__ATTR(snr1, 0664, snr_show, snr_store),
 > -__ATTR(snr2, 0664, snr_show, snr_store),
 > -__ATTR(snr3, 0664, snr_show, snr_store),
 > +__ATTR_MRO(snr0, snr_show),
 > +__ATTR_MRO(snr1, snr_show),
 > +__ATTR_MRO(snr2, snr_show),
 > +__ATTR_MRO(snr3, snr_show),
 >  };
 >  
 >  static struct device_attribute ddb_attrs_ctemp[] = {
 > -- 
 > 2.13.0


snr_store was disabled to prevent people from accidentally overwriting serial 
numbers.
Maybe it should be a driver/compile option.

[PATCH 10/14] [media] ddbridge: remove unreachable code

[Daniel Scheller]

From: Daniel Scheller 

>From smatch:

  drivers/media/pci/ddbridge/ddbridge-core.c:3490 snr_store() info: ignoring 
unreachable code.

In fact, the function immediately returns zero, so remove it and update
ddb_attrs_snr[] to not reference it anymore.

Cc: Ralph Metzler 
Signed-off-by: Daniel Scheller 
---
 drivers/media/pci/ddbridge/ddbridge-core.c | 27 ---
 1 file changed, 4 insertions(+), 23 deletions(-)

diff --git a/drivers/media/pci/ddbridge/ddbridge-core.c 
b/drivers/media/pci/ddbridge/ddbridge-core.c
index 8981795b0819..3756b9961fcd 100644
--- a/drivers/media/pci/ddbridge/ddbridge-core.c
+++ b/drivers/media/pci/ddbridge/ddbridge-core.c
@@ -3236,25 +3236,6 @@ static ssize_t snr_show(struct device *device,
return sprintf(buf, "%s\n", snr);
 }
 
-
-static ssize_t snr_store(struct device *device, struct device_attribute *attr,
-const char *buf, size_t count)
-{
-   struct ddb *dev = dev_get_drvdata(device);
-   int num = attr->attr.name[3] - 0x30;
-   u8 snr[34] = { 0x01, 0x00 };
-
-   return 0; /* NOE: remove completely? */
-   if (count > 31)
-   return -EINVAL;
-   if (dev->port[num].type >= DDB_TUNER_XO2)
-   return -EINVAL;
-   memcpy(snr + 2, buf, count);
-   i2c_write(>i2c[num].adap, 0x57, snr, 34);
-   i2c_write(>i2c[num].adap, 0x50, snr, 34);
-   return count;
-}
-
 static ssize_t bsnr_show(struct device *device,
 struct device_attribute *attr, char *buf)
 {
@@ -3394,10 +3375,10 @@ static struct device_attribute ddb_attrs_fan[] = {
 };
 
 static struct device_attribute ddb_attrs_snr[] = {
-   __ATTR(snr0, 0664, snr_show, snr_store),
-   __ATTR(snr1, 0664, snr_show, snr_store),
-   __ATTR(snr2, 0664, snr_show, snr_store),
-   __ATTR(snr3, 0664, snr_show, snr_store),
+   __ATTR_MRO(snr0, snr_show),
+   __ATTR_MRO(snr1, snr_show),
+   __ATTR_MRO(snr2, snr_show),
+   __ATTR_MRO(snr3, snr_show),
 };
 
 static struct device_attribute ddb_attrs_ctemp[] = {
-- 
2.13.0