linux-kernel - [PATCH] cpufreq: speedstep: remove unnecessary static in speedstep_detect

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Message-ID: <20170705030921.GA18166@embeddedgus>
Date:   Tue, 4 Jul 2017 22:09:21 -0500
From:   "Gustavo A. R. Silva" <garsilva@...eddedor.com>
To:     "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Viresh Kumar <viresh.kumar@...aro.org>
Cc:     linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org,
        "Gustavo A. R. Silva" <garsilva@...eddedor.com>
Subject: [PATCH] cpufreq: speedstep: remove unnecessary static in
 speedstep_detect_chipset()

Remove unnecessary static on local variable hostbridge.
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,
there is 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
   5084    3392     256    8732    221c drivers/cpufreq/speedstep-ich.o

after:
   text    data     bss     dec     hex filename
   5062    3304     192    8558    216e drivers/cpufreq/speedstep-ich.o

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

diff --git a/drivers/cpufreq/speedstep-ich.c b/drivers/cpufreq/speedstep-ich.c
index b86953a..0412a24 100644
--- a/drivers/cpufreq/speedstep-ich.c
+++ b/drivers/cpufreq/speedstep-ich.c
@@ -207,7 +207,7 @@ static unsigned int speedstep_detect_chipset(void)
 		 * 8100 which use a pretty old revision of the 82815
 		 * host bridge. Abort on these systems.
 		 */
-		static struct pci_dev *hostbridge;
+		struct pci_dev *hostbridge;
 
 		hostbridge  = pci_get_subsys(PCI_VENDOR_ID_INTEL,
 			      PCI_DEVICE_ID_INTEL_82815_MC,
-- 
2.5.0