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pinctrl: qcom: ssbi: mpp: constify gpio_chip structure

PATCH In review Gustavo A. R. Silva 3 participants 4 messages Jul 11, 2017 – Aug 2, 2017

Subsystems (5)
Arm Qualcomm mailing list GPIO Pin control Pin controller - Qualcomm +1 more subsystems
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Gustavo A. R. Silva

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#0 lore raw

PATCH 1/1 pinctrl: qcom: ssbi: mpp: constify gpio_chip structure

This structure is only used to copy into another 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
15136 5112 0 20248 4f18 drivers/pinctrl/qcom/pinctrl-ssbi-mpp.o

after:
bss dec hex filename
14849 5024 0 19873 4da1 drivers/pinctrl/qcom/pinctrl-ssbi-mpp.o

Signed-off-by Gustavo A. R. Silva <[email protected]>
---
 drivers/pinctrl/qcom/pinctrl-ssbi-mpp.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
drivers/pinctrl/qcom/pinctrl-ssbi-mpp.c +1 -1
index 0d1392f..1e513bd 100644
@@ -643,7 +643,7 @@ static void pm8xxx_mpp_dbg_show(struct seq_file *s, struct gpio_chip *chip)
 #define pm8xxx_mpp_dbg_show NULL
 #endif
 
-static struct gpio_chip pm8xxx_mpp_template = {
+static const struct gpio_chip pm8xxx_mpp_template = {
 	.direction_input = pm8xxx_mpp_direction_input,
 	.direction_output = pm8xxx_mpp_direction_output,
 	.get = pm8xxx_mpp_get,
Signature · 1 line
2.5.0
author
#2 lore raw
Quoted 6 lines · Bjorn Andersson

On Tue 11 Jul 14:18 PDT 2017, Gustavo A. R. Silva wrote:
[..]

Quoted 4 lines

before:
text data bss dec hex filename
15136 5112 0 20248 4f18 drivers/pinctrl/qcom/pinctrl-ssbi-mpp.o

Quoted 6 lines
Quoted 5 lines

after:
bss dec hex filename
14849 5024 0 19873 4da1 drivers/pinctrl/qcom/pinctrl-ssbi-mpp.o

Signed-off-by Gustavo A. R. Silva <[email protected]>
Reviewed-by Bjorn Andersson <[email protected]>

Thank you, Bjorn.

Signature · 1 line
Gustavo A. R. Silva
#3 lore raw
In reply to Gustavo A. R. Silva
Quoted 40 lines · Gustavo A. R. Silva

This structure is only used to copy into another 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
15136 5112 0 20248 4f18 drivers/pinctrl/qcom/pinctrl-ssbi-mpp.o

Quoted 5 lines

after:
bss dec hex filename
14849 5024 0 19873 4da1 drivers/pinctrl/qcom/pinctrl-ssbi-mpp.o

Signed-off-by Gustavo A. R. Silva <[email protected]>

Patch applied with Björn's review tag.

Yours,
Linus Walleij