2017-07-11 18:03:44

by Gustavo A. R. Silva

[permalink] [raw]
Subject: [PATCH] pinctrl: bcm2835: constify gpio_chip structure

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
18958 9000 128 28086 6db6 drivers/pinctrl/bcm/pinctrl-bcm2835.o

after:
text data bss dec hex filename
18764 8912 128 27804 6c9c drivers/pinctrl/bcm/pinctrl-bcm2835.o

Signed-off-by: Gustavo A. R. Silva <[email protected]>
---
drivers/pinctrl/bcm/pinctrl-bcm2835.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/pinctrl/bcm/pinctrl-bcm2835.c b/drivers/pinctrl/bcm/pinctrl-bcm2835.c
index 2308831..7203f35 100644
--- a/drivers/pinctrl/bcm/pinctrl-bcm2835.c
+++ b/drivers/pinctrl/bcm/pinctrl-bcm2835.c
@@ -353,7 +353,7 @@ static int bcm2835_gpio_direction_output(struct gpio_chip *chip,
return pinctrl_gpio_direction_output(chip->base + offset);
}

-static struct gpio_chip bcm2835_gpio_chip = {
+static const struct gpio_chip bcm2835_gpio_chip = {
.label = MODULE_NAME,
.owner = THIS_MODULE,
.request = gpiochip_generic_request,
--
2.5.0


2017-07-12 19:13:21

by Eric Anholt

[permalink] [raw]
Subject: Re: [PATCH] pinctrl: bcm2835: constify gpio_chip structure

"Gustavo A. R. Silva" <[email protected]> writes:

> 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:

Acked-by: Eric Anholt <[email protected]>

> ---
> drivers/pinctrl/bcm/pinctrl-bcm2835.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/pinctrl/bcm/pinctrl-bcm2835.c b/drivers/pinctrl/bcm/pinctrl-bcm2835.c
> index 2308831..7203f35 100644
> --- a/drivers/pinctrl/bcm/pinctrl-bcm2835.c
> +++ b/drivers/pinctrl/bcm/pinctrl-bcm2835.c
> @@ -353,7 +353,7 @@ static int bcm2835_gpio_direction_output(struct gpio_chip *chip,
> return pinctrl_gpio_direction_output(chip->base + offset);
> }
>
> -static struct gpio_chip bcm2835_gpio_chip = {
> +static const struct gpio_chip bcm2835_gpio_chip = {
> .label = MODULE_NAME,
> .owner = THIS_MODULE,
> .request = gpiochip_generic_request,
> --
> 2.5.0


Attachments:
signature.asc (832.00 B)

2017-07-17 04:12:19

by Gustavo A. R. Silva

[permalink] [raw]
Subject: Re: [PATCH] pinctrl: bcm2835: constify gpio_chip structure



On 07/12/2017 02:13 PM, Eric Anholt wrote:
> "Gustavo A. R. Silva" <[email protected]> writes:
>
>> 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:
> Acked-by: Eric Anholt <[email protected]>

Thank you, Eric

>> ---
>> drivers/pinctrl/bcm/pinctrl-bcm2835.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/pinctrl/bcm/pinctrl-bcm2835.c b/drivers/pinctrl/bcm/pinctrl-bcm2835.c
>> index 2308831..7203f35 100644
>> --- a/drivers/pinctrl/bcm/pinctrl-bcm2835.c
>> +++ b/drivers/pinctrl/bcm/pinctrl-bcm2835.c
>> @@ -353,7 +353,7 @@ static int bcm2835_gpio_direction_output(struct gpio_chip *chip,
>> return pinctrl_gpio_direction_output(chip->base + offset);
>> }
>>
>> -static struct gpio_chip bcm2835_gpio_chip = {
>> +static const struct gpio_chip bcm2835_gpio_chip = {
>> .label = MODULE_NAME,
>> .owner = THIS_MODULE,
>> .request = gpiochip_generic_request,
>> --
>> 2.5.0

--
Gustavo A. R. Silva

2017-08-02 08:25:55

by Linus Walleij

[permalink] [raw]
Subject: Re: [PATCH] pinctrl: bcm2835: constify gpio_chip structure

On Tue, Jul 11, 2017 at 8:03 PM, Gustavo A. R. Silva
<[email protected]> 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
> 18958 9000 128 28086 6db6 drivers/pinctrl/bcm/pinctrl-bcm2835.o
>
> after:
> text data bss dec hex filename
> 18764 8912 128 27804 6c9c drivers/pinctrl/bcm/pinctrl-bcm2835.o
>
> Signed-off-by: Gustavo A. R. Silva <[email protected]>

Patch applied with Eric's ACK.

Yours,
Linus Walleij