[PATCH] pinctrl: bcm2835: constify gpio_chip structure
From: Linus Walleij <hidden>
Date: 2017-08-02 08:25:55
Also in:
linux-gpio, lkml
From: Linus Walleij <hidden>
Date: 2017-08-02 08:25:55
Also in:
linux-gpio, lkml
On Tue, Jul 11, 2017 at 8:03 PM, Gustavo A. R. Silva [off-list ref] 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 at p = { ... };
@ok@
identifier r.i;
expression e;
position p;
@@
e = i at p;
@bad@
position p != {r.p,ok.p};
identifier r.i;
struct gpio_chip e;
@@
e at 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 <redacted>Patch applied with Eric's ACK. Yours, Linus Walleij