linux-kernel - [PATCH] mfd: max8925-i2c: remove unnecessary static in max8925

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Date:   Tue, 4 Jul 2017 14:06:34 -0500
From:   "Gustavo A. R. Silva" <garsilva@...eddedor.com>
To:     Lee Jones <lee.jones@...aro.org>
Cc:     linux-kernel@...r.kernel.org,
        "Gustavo A. R. Silva" <garsilva@...eddedor.com>
Subject: [PATCH] mfd: max8925-i2c: remove unnecessary static in
 max8925_probe()

Remove unnecessary static on local variable _chip_.
Such variable is initialized before being used,
on every execution path throughout the function.
The static has no benefit and, removing it reduces
the code size.

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

@bad exists@
position p;
identifier x;
type T;
@@

static T x@p;
...
x = <+...x...+>

@@
identifier x;
expression e;
type T;
position p != bad.p;
@@

-static
 T x@p;
 ... when != x
     when strict
?x = e;

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

before:
   text	   data	    bss	    dec	    hex	filename
   4188	   1336	    128	   5652	   1614	drivers/mfd/max8925-i2c.o

after:
   text	   data	    bss	    dec	    hex	filename
   4135	   1280	     64	   5479	   1567	drivers/mfd/max8925-i2c.o

Signed-off-by: Gustavo A. R. Silva <garsilva@...eddedor.com>
---
 drivers/mfd/max8925-i2c.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/mfd/max8925-i2c.c b/drivers/mfd/max8925-i2c.c
index 5c80aea..1006323 100644
--- a/drivers/mfd/max8925-i2c.c
+++ b/drivers/mfd/max8925-i2c.c
@@ -151,7 +151,7 @@ static int max8925_probe(struct i2c_client *client,
 				   const struct i2c_device_id *id)
 {
 	struct max8925_platform_data *pdata = dev_get_platdata(&client->dev);
-	static struct max8925_chip *chip;
+	struct max8925_chip *chip;
 	struct device_node *node = client->dev.of_node;
 
 	if (node && !pdata) {
-- 
2.5.0