linux-kernel - [PATCH] irqchip/gic/realview: remove unnecessary static in realview_gic_of

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Date:   Tue, 4 Jul 2017 16:26:22 -0500
From:   "Gustavo A. R. Silva" <garsilva@...eddedor.com>
To:     Thomas Gleixner <tglx@...utronix.de>,
        Jason Cooper <jason@...edaemon.net>,
        Marc Zyngier <marc.zyngier@....com>
Cc:     linux-kernel@...r.kernel.org,
        "Gustavo A. R. Silva" <garsilva@...eddedor.com>
Subject: [PATCH] irqchip/gic/realview: remove unnecessary static in
 realview_gic_of_init()

Remove unnecessary static on local variable _map_.
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. Also,
notice that the bss segment size is reduced down to zero. This log is
the output of the size command, before and after the code change:

before:
   text    data     bss     dec     hex filename
   2187     272      64    2523     9db drivers/irqchip/irq-gic-realview.o

after:
   text    data     bss     dec     hex filename
   2171     216       0    2387     953 drivers/irqchip/irq-gic-realview.o

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

diff --git a/drivers/irqchip/irq-gic-realview.c b/drivers/irqchip/irq-gic-realview.c
index 54c2964..18d58d2 100644
--- a/drivers/irqchip/irq-gic-realview.c
+++ b/drivers/irqchip/irq-gic-realview.c
@@ -43,7 +43,7 @@ static const struct of_device_id syscon_pldset_of_match[] = {
 static int __init
 realview_gic_of_init(struct device_node *node, struct device_node *parent)
 {
-	static struct regmap *map;
+	struct regmap *map;
 	struct device_node *np;
 	const struct of_device_id *gic_id;
 	u32 pld1_ctrl;
-- 
2.5.0