Thread (4 messages) 4 messages, 3 authors, 2017-08-02

[PATCH] pinctrl: bcm2835: constify gpio_chip structure

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
Keyboard shortcuts
hback out one level
jnext message in thread
kprevious message in thread
ldrill in
Escclose help / fold thread tree
?toggle this help