[PATCH 0/2] fixes for ib-mfd-gpio-i2c-3.19

[PATCH 0/2] fixes for ib-mfd-gpio-i2c-3.19

[Octavian Purdila]

Hi Lee,

A couple of patches that fixes a coccinelle warning found by Julia and
kbuild test robot. They are not critical and I don't know if they must
be pull through ib-mfd-gpio-i2c-3.19, please let me know if I need to
submit them elsewhere.

Thanks,
Tavi


Octavian Purdila (2):
  mfd: dln2: fix _dln2_transfer return code
  i2c: dln2: simplify return flow for dln2_i2c_enable

 drivers/i2c/busses/i2c-dln2.c | 7 +------
 drivers/mfd/dln2.c            | 3 ++-
 2 files changed, 3 insertions(+), 7 deletions(-)

-- 
1.9.1

[PATCH 1/2] mfd: dln2: fix _dln2_transfer return code

[Octavian Purdila]

If wait_for_completion_interruptible_timeout returns a positive value
it may be propagated as the return value of _dln2_transfer. This
contradicts the documentation of the function and exposes unnecessary
internals to the callers.

This patch makes sure to set the return value to 0 in that case.

Reported-by: Julia Lawall <julia.lawall@lip6.fr>
Signed-off-by: Octavian Purdila <octavian.purdila@intel.com>
---
 drivers/mfd/dln2.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/mfd/dln2.c b/drivers/mfd/dln2.c
index 9765a17..f0747a1 100644
--- a/drivers/mfd/dln2.c
+++ b/drivers/mfd/dln2.c
@@ -462,7 +462,8 @@ static int _dln2_transfer(struct dln2_dev *dln2, u16 handle, u16 cmd,
 		if (!ret)
 			ret = -ETIMEDOUT;
 		goto out_free_rx_slot;
-	}
+	} else
+		ret = 0;
 
 	if (dln2->disconnect) {
 		ret = -ENODEV;
-- 
1.9.1

Re: [PATCH 1/2] mfd: dln2: fix _dln2_transfer return code

[Johan Hovold]

On Tue, Nov 11, 2014 at 02:20:56PM +0200, Octavian Purdila wrote:
> If wait_for_completion_interruptible_timeout returns a positive value
> it may be propagated as the return value of _dln2_transfer. This
> contradicts the documentation of the function and exposes unnecessary
> internals to the callers.
> 
> This patch makes sure to set the return value to 0 in that case.
> 
> Reported-by: Julia Lawall <julia.lawall@lip6.fr>
> Signed-off-by: Octavian Purdila <octavian.purdila@intel.com>
> ---
>  drivers/mfd/dln2.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/mfd/dln2.c b/drivers/mfd/dln2.c
> index 9765a17..f0747a1 100644
> --- a/drivers/mfd/dln2.c
> +++ b/drivers/mfd/dln2.c
> @@ -462,7 +462,8 @@ static int _dln2_transfer(struct dln2_dev *dln2, u16 handle, u16 cmd,
>  		if (!ret)
>  			ret = -ETIMEDOUT;
>  		goto out_free_rx_slot;
> -	}
> +	} else
> +		ret = 0;

You need braces on both branches (without commenting on the fix itself).

Johan

Re: [PATCH 1/2] mfd: dln2: fix _dln2_transfer return code

[Julia Lawall]

On Tue, 11 Nov 2014, Octavian Purdila wrote:

> If wait_for_completion_interruptible_timeout returns a positive value
> it may be propagated as the return value of _dln2_transfer. This
> contradicts the documentation of the function and exposes unnecessary
> internals to the callers.
> 
> This patch makes sure to set the return value to 0 in that case.

I didn't keep around the code or the address of the git tree, but I wonder 
if this makes a later assignment of ret to 0 unnecessary?

julia

> Reported-by: Julia Lawall <julia.lawall@lip6.fr>
> Signed-off-by: Octavian Purdila <octavian.purdila@intel.com>
> ---
>  drivers/mfd/dln2.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/mfd/dln2.c b/drivers/mfd/dln2.c
> index 9765a17..f0747a1 100644
> --- a/drivers/mfd/dln2.c
> +++ b/drivers/mfd/dln2.c
> @@ -462,7 +462,8 @@ static int _dln2_transfer(struct dln2_dev *dln2, u16 handle, u16 cmd,
>  		if (!ret)
>  			ret = -ETIMEDOUT;
>  		goto out_free_rx_slot;
> -	}
> +	} else
> +		ret = 0;
>  
>  	if (dln2->disconnect) {
>  		ret = -ENODEV;
> -- 
> 1.9.1
> 
> 

Re: [PATCH 1/2] mfd: dln2: fix _dln2_transfer return code

[Octavian Purdila]

On Tue, Nov 11, 2014 at 6:18 PM, Julia Lawall <julia.lawall@lip6.fr> wrote:
> On Tue, 11 Nov 2014, Octavian Purdila wrote:
>
>> If wait_for_completion_interruptible_timeout returns a positive value
>> it may be propagated as the return value of _dln2_transfer. This
>> contradicts the documentation of the function and exposes unnecessary
>> internals to the callers.
>>
>> This patch makes sure to set the return value to 0 in that case.
>
> I didn't keep around the code or the address of the git tree, but I wonder
> if this makes a later assignment of ret to 0 unnecessary?
>

Yes, you are right, we can skip setting it when ibuf is NULL. I will
send v2 that fixes this and the coding style issue.

[PATCH 2/2] i2c: dln2: simplify return flow for dln2_i2c_enable

[Octavian Purdila]

This fixes the following kbuild test robot warning:

>> drivers/i2c/busses/i2c-dln2.c:70:1-4: WARNING: end returns can be simplified if negative or 0 value

Reported-by: kbuild test robot <fengguang.wu@intel.com>
Reported-by: Julia Lawall <julia.lawall@lip6.fr>

Signed-off-by: Octavian Purdila <octavian.purdila@intel.com>
---
 drivers/i2c/busses/i2c-dln2.c | 7 +------
 1 file changed, 1 insertion(+), 6 deletions(-)

diff --git a/drivers/i2c/busses/i2c-dln2.c b/drivers/i2c/busses/i2c-dln2.c
index 010a5fa..b3fb86a 100644
--- a/drivers/i2c/busses/i2c-dln2.c
+++ b/drivers/i2c/busses/i2c-dln2.c
@@ -54,7 +54,6 @@ struct dln2_i2c {
 
 static int dln2_i2c_enable(struct dln2_i2c *dln2, bool enable)
 {
-	int ret;
 	u16 cmd;
 	struct {
 		u8 port;
@@ -67,11 +66,7 @@ static int dln2_i2c_enable(struct dln2_i2c *dln2, bool enable)
 	else
 		cmd = DLN2_I2C_DISABLE;
 
-	ret = dln2_transfer_tx(dln2->pdev, cmd, &tx, sizeof(tx));
-	if (ret < 0)
-		return ret;
-
-	return 0;
+	return dln2_transfer_tx(dln2->pdev, cmd, &tx, sizeof(tx));
 }
 
 static int dln2_i2c_write(struct dln2_i2c *dln2, u8 addr,
-- 
1.9.1

Re: [PATCH 2/2] i2c: dln2: simplify return flow for dln2_i2c_enable

[Johan Hovold]

On Tue, Nov 11, 2014 at 02:20:57PM +0200, Octavian Purdila wrote:
> This fixes the following kbuild test robot warning:
> 
> >> drivers/i2c/busses/i2c-dln2.c:70:1-4: WARNING: end returns can be simplified if negative or 0 value
> 
> Reported-by: kbuild test robot <fengguang.wu@intel.com>
> Reported-by: Julia Lawall <julia.lawall@lip6.fr>
> 
> Signed-off-by: Octavian Purdila <octavian.purdila@intel.com>
> ---
>  drivers/i2c/busses/i2c-dln2.c | 7 +------
>  1 file changed, 1 insertion(+), 6 deletions(-)
> 
> diff --git a/drivers/i2c/busses/i2c-dln2.c b/drivers/i2c/busses/i2c-dln2.c
> index 010a5fa..b3fb86a 100644
> --- a/drivers/i2c/busses/i2c-dln2.c
> +++ b/drivers/i2c/busses/i2c-dln2.c
> @@ -54,7 +54,6 @@ struct dln2_i2c {
>  
>  static int dln2_i2c_enable(struct dln2_i2c *dln2, bool enable)
>  {
> -	int ret;
>  	u16 cmd;
>  	struct {
>  		u8 port;
> @@ -67,11 +66,7 @@ static int dln2_i2c_enable(struct dln2_i2c *dln2, bool enable)
>  	else
>  		cmd = DLN2_I2C_DISABLE;
>  
> -	ret = dln2_transfer_tx(dln2->pdev, cmd, &tx, sizeof(tx));
> -	if (ret < 0)
> -		return ret;
> -
> -	return 0;
> +	return dln2_transfer_tx(dln2->pdev, cmd, &tx, sizeof(tx));

This looks like a bogus warning. It's not generally equivalent (ret > 0)
and is not mandated by any style guide lines.

Johan

Re: [PATCH 2/2] i2c: dln2: simplify return flow for dln2_i2c_enable

[Octavian Purdila]

On Tue, Nov 11, 2014 at 2:26 PM, Johan Hovold <johan@kernel.org> wrote:
> On Tue, Nov 11, 2014 at 02:20:57PM +0200, Octavian Purdila wrote:
>> This fixes the following kbuild test robot warning:
>>
>> >> drivers/i2c/busses/i2c-dln2.c:70:1-4: WARNING: end returns can be simplified if negative or 0 value
>>
>> Reported-by: kbuild test robot <fengguang.wu@intel.com>
>> Reported-by: Julia Lawall <julia.lawall@lip6.fr>
>>
>> Signed-off-by: Octavian Purdila <octavian.purdila@intel.com>
>> ---
>>  drivers/i2c/busses/i2c-dln2.c | 7 +------
>>  1 file changed, 1 insertion(+), 6 deletions(-)
>>
>> diff --git a/drivers/i2c/busses/i2c-dln2.c b/drivers/i2c/busses/i2c-dln2.c
>> index 010a5fa..b3fb86a 100644
>> --- a/drivers/i2c/busses/i2c-dln2.c
>> +++ b/drivers/i2c/busses/i2c-dln2.c
>> @@ -54,7 +54,6 @@ struct dln2_i2c {
>>
>>  static int dln2_i2c_enable(struct dln2_i2c *dln2, bool enable)
>>  {
>> -     int ret;
>>       u16 cmd;
>>       struct {
>>               u8 port;
>> @@ -67,11 +66,7 @@ static int dln2_i2c_enable(struct dln2_i2c *dln2, bool enable)
>>       else
>>               cmd = DLN2_I2C_DISABLE;
>>
>> -     ret = dln2_transfer_tx(dln2->pdev, cmd, &tx, sizeof(tx));
>> -     if (ret < 0)
>> -             return ret;
>> -
>> -     return 0;
>> +     return dln2_transfer_tx(dln2->pdev, cmd, &tx, sizeof(tx));
>
> This looks like a bogus warning. It's not generally equivalent (ret > 0)
> and is not mandated by any style guide lines.
>

In this particular it should be equivalent (with the previous fix) and
it saves 5 lines, so I think its worth it.

Re: [PATCH 2/2] i2c: dln2: simplify return flow for dln2_i2c_enable

[Julia Lawall]

On Tue, 11 Nov 2014, Octavian Purdila wrote:

> On Tue, Nov 11, 2014 at 2:26 PM, Johan Hovold <johan@kernel.org> wrote:
> > On Tue, Nov 11, 2014 at 02:20:57PM +0200, Octavian Purdila wrote:
> >> This fixes the following kbuild test robot warning:
> >>
> >> >> drivers/i2c/busses/i2c-dln2.c:70:1-4: WARNING: end returns can be simplified if negative or 0 value
> >>
> >> Reported-by: kbuild test robot <fengguang.wu@intel.com>
> >> Reported-by: Julia Lawall <julia.lawall@lip6.fr>
> >>
> >> Signed-off-by: Octavian Purdila <octavian.purdila@intel.com>
> >> ---
> >>  drivers/i2c/busses/i2c-dln2.c | 7 +------
> >>  1 file changed, 1 insertion(+), 6 deletions(-)
> >>
> >> diff --git a/drivers/i2c/busses/i2c-dln2.c b/drivers/i2c/busses/i2c-dln2.c
> >> index 010a5fa..b3fb86a 100644
> >> --- a/drivers/i2c/busses/i2c-dln2.c
> >> +++ b/drivers/i2c/busses/i2c-dln2.c
> >> @@ -54,7 +54,6 @@ struct dln2_i2c {
> >>
> >>  static int dln2_i2c_enable(struct dln2_i2c *dln2, bool enable)
> >>  {
> >> -     int ret;
> >>       u16 cmd;
> >>       struct {
> >>               u8 port;
> >> @@ -67,11 +66,7 @@ static int dln2_i2c_enable(struct dln2_i2c *dln2, bool enable)
> >>       else
> >>               cmd = DLN2_I2C_DISABLE;
> >>
> >> -     ret = dln2_transfer_tx(dln2->pdev, cmd, &tx, sizeof(tx));
> >> -     if (ret < 0)
> >> -             return ret;
> >> -
> >> -     return 0;
> >> +     return dln2_transfer_tx(dln2->pdev, cmd, &tx, sizeof(tx));
> >
> > This looks like a bogus warning. It's not generally equivalent (ret > 0)
> > and is not mandated by any style guide lines.
> >
> 
> In this particular it should be equivalent (with the previous fix) and
> it saves 5 lines, so I think its worth it.

It's marked as a warning because it is not generally equivalent.  But 
there may be many cases where it is equivalent, and in this case the 
documentation for the function said that it should have been.  So I think 
that the warning is useful.

julia

Re: [PATCH 2/2] i2c: dln2: simplify return flow for dln2_i2c_enable

[Johan Hovold]

On Tue, Nov 11, 2014 at 05:20:37PM +0100, Julia Lawall wrote:
> On Tue, 11 Nov 2014, Octavian Purdila wrote:
> 
> > On Tue, Nov 11, 2014 at 2:26 PM, Johan Hovold <johan@kernel.org> wrote:
> > > On Tue, Nov 11, 2014 at 02:20:57PM +0200, Octavian Purdila wrote:
> > >> This fixes the following kbuild test robot warning:
> > >>
> > >> >> drivers/i2c/busses/i2c-dln2.c:70:1-4: WARNING: end returns can be simplified if negative or 0 value
> > >>
> > >> Reported-by: kbuild test robot <fengguang.wu@intel.com>
> > >> Reported-by: Julia Lawall <julia.lawall@lip6.fr>
> > >>
> > >> Signed-off-by: Octavian Purdila <octavian.purdila@intel.com>
> > >> ---
> > >>  drivers/i2c/busses/i2c-dln2.c | 7 +------
> > >>  1 file changed, 1 insertion(+), 6 deletions(-)
> > >>
> > >> diff --git a/drivers/i2c/busses/i2c-dln2.c b/drivers/i2c/busses/i2c-dln2.c
> > >> index 010a5fa..b3fb86a 100644
> > >> --- a/drivers/i2c/busses/i2c-dln2.c
> > >> +++ b/drivers/i2c/busses/i2c-dln2.c
> > >> @@ -54,7 +54,6 @@ struct dln2_i2c {
> > >>
> > >>  static int dln2_i2c_enable(struct dln2_i2c *dln2, bool enable)
> > >>  {
> > >> -     int ret;
> > >>       u16 cmd;
> > >>       struct {
> > >>               u8 port;
> > >> @@ -67,11 +66,7 @@ static int dln2_i2c_enable(struct dln2_i2c *dln2, bool enable)
> > >>       else
> > >>               cmd = DLN2_I2C_DISABLE;
> > >>
> > >> -     ret = dln2_transfer_tx(dln2->pdev, cmd, &tx, sizeof(tx));
> > >> -     if (ret < 0)
> > >> -             return ret;
> > >> -
> > >> -     return 0;
> > >> +     return dln2_transfer_tx(dln2->pdev, cmd, &tx, sizeof(tx));
> > >
> > > This looks like a bogus warning. It's not generally equivalent (ret > 0)
> > > and is not mandated by any style guide lines.
> > >
> > 
> > In this particular it should be equivalent (with the previous fix) and
> > it saves 5 lines, so I think its worth it.
> 
> It's marked as a warning because it is not generally equivalent.  But 
> there may be many cases where it is equivalent, and in this case the 
> documentation for the function said that it should have been.  So I think 
> that the warning is useful.

I still think "warning" is too strong, "hint" would perhaps be more
appropriate, if at all needed.

Sure we can save four lines of code this way, but we also hide the
return value of the function so that instead of just looking at the
function itself I now have to look at the documentation of the final
function call (and hope it is up to date) to figure out the return
value (e.g. it may return the number of bytes transfered on success).

I also believe using a temporary is preferred for purely aesthetic
reasons in case the final function call has enough parameters that it
needs to use continuation lines.

Johan

Re: [PATCH 2/2] i2c: dln2: simplify return flow for dln2_i2c_enable

[Wolfram Sang]

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On Tue, Nov 11, 2014 at 02:20:57PM +0200, Octavian Purdila wrote:
> This fixes the following kbuild test robot warning:
> 
> >> drivers/i2c/busses/i2c-dln2.c:70:1-4: WARNING: end returns can be simplified if negative or 0 value
> 
> Reported-by: kbuild test robot <fengguang.wu@intel.com>
> Reported-by: Julia Lawall <julia.lawall@lip6.fr>
> 
> Signed-off-by: Octavian Purdila <octavian.purdila@intel.com>

Acked-by: Wolfram Sang <wsa@the-dreams.de>

Lee, I think it is easiest if you simply add it to the branch you have
for this driver. OK?


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Re: [PATCH 2/2] i2c: dln2: simplify return flow for dln2_i2c_enable

[Lee Jones]

On Thu, 13 Nov 2014, Wolfram Sang wrote:

> On Tue, Nov 11, 2014 at 02:20:57PM +0200, Octavian Purdila wrote:
> > This fixes the following kbuild test robot warning:
> > 
> > >> drivers/i2c/busses/i2c-dln2.c:70:1-4: WARNING: end returns can be simplified if negative or 0 value
> > 
> > Reported-by: kbuild test robot <fengguang.wu@intel.com>
> > Reported-by: Julia Lawall <julia.lawall@lip6.fr>
> > 
> > Signed-off-by: Octavian Purdila <octavian.purdila@intel.com>
> 
> Acked-by: Wolfram Sang <wsa@the-dreams.de>
> 
> Lee, I think it is easiest if you simply add it to the branch you have
> for this driver. OK?

Octavian indicated that he needs to send a v2 of the second patch.  I
assume he will add your Ack to this patch when he does with a note
saying that it needs to be added to the I2C IB.

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog

Re: [PATCH 2/2] i2c: dln2: simplify return flow for dln2_i2c_enable

[Octavian Purdila]

On Mon, Nov 17, 2014 at 4:56 PM, Lee Jones <lee.jones@linaro.org> wrote:
>
> On Thu, 13 Nov 2014, Wolfram Sang wrote:
>
> > On Tue, Nov 11, 2014 at 02:20:57PM +0200, Octavian Purdila wrote:
> > > This fixes the following kbuild test robot warning:
> > >
> > > >> drivers/i2c/busses/i2c-dln2.c:70:1-4: WARNING: end returns can be simplified if negative or 0 value
> > >
> > > Reported-by: kbuild test robot <fengguang.wu@intel.com>
> > > Reported-by: Julia Lawall <julia.lawall@lip6.fr>
> > >
> > > Signed-off-by: Octavian Purdila <octavian.purdila@intel.com>
> >
> > Acked-by: Wolfram Sang <wsa@the-dreams.de>
> >
> > Lee, I think it is easiest if you simply add it to the branch you have
> > for this driver. OK?
>
> Octavian indicated that he needs to send a v2 of the second patch.  I
> assume he will add your Ack to this patch when he does with a note
> saying that it needs to be added to the I2C IB.
>

Hi Lee,

Yes, I will to that, and add a couple more fixes from Dan Carpenter, a
little bit later tonight.