[PATCH] pinctrl: qcom: msm: constify gpio_chip structure

[PATCH] pinctrl: qcom: msm: constify gpio_chip structure

[Gustavo A. R. Silva]

This structure is only used to copy into other structure, so declare
it as const.

This issue was detected using Coccinelle and the following semantic patch:

@r disable optional_qualifier@
identifier i;
position p;
@@
static struct gpio_chip i@p = { ... };

@ok@
identifier r.i;
expression e;
position p;
@@
e = i@p;

@bad@
position p != {r.p,ok.p};
identifier r.i;
struct gpio_chip e;
@@
e@i@p

@depends on !bad disable optional_qualifier@
identifier r.i;
@@
static
+const
 struct gpio_chip i = { ... };

In the following log you can see a significant difference in the code size
and data segment, hence in the dec segment. This log is the output
of the size command, before and after the code change:

before:
   text    data     bss     dec     hex filename
  13129    2808     192   16129    3f01 drivers/pinctrl/qcom/pinctrl-msm.o

after:
   text    data     bss     dec     hex filename
  12839    2720     192   15751    3d87 drivers/pinctrl/qcom/pinctrl-msm.o

Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
---
 drivers/pinctrl/qcom/pinctrl-msm.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/pinctrl/qcom/pinctrl-msm.c b/drivers/pinctrl/qcom/pinctrl-msm.c
index 273badd..245ccfd 100644
--- a/drivers/pinctrl/qcom/pinctrl-msm.c
+++ b/drivers/pinctrl/qcom/pinctrl-msm.c
@@ -521,7 +521,7 @@ static void msm_gpio_dbg_show(struct seq_file *s, struct gpio_chip *chip)
 #define msm_gpio_dbg_show NULL
 #endif
 
-static struct gpio_chip msm_gpio_template = {
+static const struct gpio_chip msm_gpio_template = {
 	.direction_input  = msm_gpio_direction_input,
 	.direction_output = msm_gpio_direction_output,
 	.get_direction    = msm_gpio_get_direction,
-- 
2.5.0

Re: [PATCH] pinctrl: qcom: msm: constify gpio_chip structure

[Bjorn Andersson]

On Tue 11 Jul 11:34 PDT 2017, Gustavo A. R. Silva wrote:
[..]
> In the following log you can see a significant difference in the code size
> and data segment, hence in the dec segment. This log is the output

"dec" is for "decimal" and is the sum of text, data and bss...

> of the size command, before and after the code change:
> 
> before:
>    text    data     bss     dec     hex filename
>   13129    2808     192   16129    3f01 drivers/pinctrl/qcom/pinctrl-msm.o
> 
> after:
>    text    data     bss     dec     hex filename
>   12839    2720     192   15751    3d87 drivers/pinctrl/qcom/pinctrl-msm.o
> 
> Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>

Good catch, thanks!

Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>

Regards,
Bjorn

> ---
>  drivers/pinctrl/qcom/pinctrl-msm.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/pinctrl/qcom/pinctrl-msm.c b/drivers/pinctrl/qcom/pinctrl-msm.c
> index 273badd..245ccfd 100644
> --- a/drivers/pinctrl/qcom/pinctrl-msm.c
> +++ b/drivers/pinctrl/qcom/pinctrl-msm.c
> @@ -521,7 +521,7 @@ static void msm_gpio_dbg_show(struct seq_file *s, struct gpio_chip *chip)
>  #define msm_gpio_dbg_show NULL
>  #endif
>  
> -static struct gpio_chip msm_gpio_template = {
> +static const struct gpio_chip msm_gpio_template = {
>  	.direction_input  = msm_gpio_direction_input,
>  	.direction_output = msm_gpio_direction_output,
>  	.get_direction    = msm_gpio_get_direction,
> -- 
> 2.5.0
> 

Re: [PATCH] pinctrl: qcom: msm: constify gpio_chip structure

[Gustavo A. R. Silva]

Hi Bjorn,

Quoting Bjorn Andersson <bjorn.andersson@linaro.org>:

> On Tue 11 Jul 11:34 PDT 2017, Gustavo A. R. Silva wrote:
> [..]
>> In the following log you can see a significant difference in the code size
>> and data segment, hence in the dec segment. This log is the output
>
> "dec" is for "decimal" and is the sum of text, data and bss...
>

You are right. :)

>> of the size command, before and after the code change:
>>
>> before:
>>    text    data     bss     dec     hex filename
>>   13129    2808     192   16129    3f01 drivers/pinctrl/qcom/pinctrl-msm.o
>>
>> after:
>>    text    data     bss     dec     hex filename
>>   12839    2720     192   15751    3d87 drivers/pinctrl/qcom/pinctrl-msm.o
>>
>> Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
>
> Good catch, thanks!
>

Absolutely, glad to help!

> Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
>
> Regards,
> Bjorn
>
>> ---
>>  drivers/pinctrl/qcom/pinctrl-msm.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/pinctrl/qcom/pinctrl-msm.c  
>> b/drivers/pinctrl/qcom/pinctrl-msm.c
>> index 273badd..245ccfd 100644
>> --- a/drivers/pinctrl/qcom/pinctrl-msm.c
>> +++ b/drivers/pinctrl/qcom/pinctrl-msm.c
>> @@ -521,7 +521,7 @@ static void msm_gpio_dbg_show(struct seq_file  
>> *s, struct gpio_chip *chip)
>>  #define msm_gpio_dbg_show NULL
>>  #endif
>>
>> -static struct gpio_chip msm_gpio_template = {
>> +static const struct gpio_chip msm_gpio_template = {
>>  	.direction_input  = msm_gpio_direction_input,
>>  	.direction_output = msm_gpio_direction_output,
>>  	.get_direction    = msm_gpio_get_direction,
>> --
>> 2.5.0
>>

--
Gustavo A. R. Silva

Re: [PATCH] pinctrl: qcom: msm: constify gpio_chip structure

[Linus Walleij]

On Tue, Jul 11, 2017 at 8:34 PM, Gustavo A. R. Silva
<garsilva@embeddedor.com> wrote:

> This structure is only used to copy into other structure, so declare
> it as const.
>
> This issue was detected using Coccinelle and the following semantic patch:
>
> @r disable optional_qualifier@
> identifier i;
> position p;
> @@
> static struct gpio_chip i@p = { ... };
>
> @ok@
> identifier r.i;
> expression e;
> position p;
> @@
> e = i@p;
>
> @bad@
> position p != {r.p,ok.p};
> identifier r.i;
> struct gpio_chip e;
> @@
> e@i@p
>
> @depends on !bad disable optional_qualifier@
> identifier r.i;
> @@
> static
> +const
>  struct gpio_chip i = { ... };
>
> In the following log you can see a significant difference in the code size
> and data segment, hence in the dec segment. This log is the output
> of the size command, before and after the code change:
>
> before:
>    text    data     bss     dec     hex filename
>   13129    2808     192   16129    3f01 drivers/pinctrl/qcom/pinctrl-msm.o
>
> after:
>    text    data     bss     dec     hex filename
>   12839    2720     192   15751    3d87 drivers/pinctrl/qcom/pinctrl-msm.o
>
> Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>

Patch applied with Björn's ACK.

Yours,
Linus Walleij