linux-kernel - [PATCH 2/8] arch/x86/kernel/cpu/cpufreq: Fix unsigned return type

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Date:	Sun,  5 Sep 2010 21:00:20 +0200
From:	Julia Lawall <julia@...u.dk>
To:	Dave Jones <davej@...hat.com>
Cc:	kernel-janitors@...r.kernel.org,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	"H. Peter Anvin" <hpa@...or.com>, x86@...nel.org,
	cpufreq@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH 2/8] arch/x86/kernel/cpu/cpufreq: Fix unsigned return type

In each case, the function has an unsigned return type, but returns a
negative constant to indicate an error condition.  Each function is only
called once.  For nforce2_detect_chipset, the result is only compared to 0,
and for longrun_determine_freqs, the result is stored in a variable of type
(signed) int.  Thus, for both functions, unsigned can be dropped from the
return type.

A sematic match that finds this problem is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@exists@
identifier f;
constant C;
@@

 unsigned f(...)
 { <+...
*  return -C;
 ...+> }
// </smpl>

Signed-off-by: Julia Lawall <julia@...u.dk>

---
 arch/x86/kernel/cpu/cpufreq/cpufreq-nforce2.c |    2 +-
 arch/x86/kernel/cpu/cpufreq/longrun.c         |    2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/cpu/cpufreq/cpufreq-nforce2.c b/arch/x86/kernel/cpu/cpufreq/cpufreq-nforce2.c
index 733093d..141abeb 100644
--- a/arch/x86/kernel/cpu/cpufreq/cpufreq-nforce2.c
+++ b/arch/x86/kernel/cpu/cpufreq/cpufreq-nforce2.c
@@ -393,7 +393,7 @@ static struct cpufreq_driver nforce2_driver = {
  * Detects nForce2 A2 and C1 stepping
  *
  */
-static unsigned int nforce2_detect_chipset(void)
+static int nforce2_detect_chipset(void)
 {
 	nforce2_dev = pci_get_subsys(PCI_VENDOR_ID_NVIDIA,
 					PCI_DEVICE_ID_NVIDIA_NFORCE2,
diff --git a/arch/x86/kernel/cpu/cpufreq/longrun.c b/arch/x86/kernel/cpu/cpufreq/longrun.c
index fc09f14..77945bf 100644
--- a/arch/x86/kernel/cpu/cpufreq/longrun.c
+++ b/arch/x86/kernel/cpu/cpufreq/longrun.c
@@ -165,7 +165,7 @@ static unsigned int longrun_get(unsigned int cpu)
  * TMTA rules:
  * performance_pctg = (target_freq - low_freq)/(high_freq - low_freq)
  */
-static unsigned int __cpuinit longrun_determine_freqs(unsigned int *low_freq,
+static int __cpuinit longrun_determine_freqs(unsigned int *low_freq,
 						      unsigned int *high_freq)
 {
 	u32 msr_lo, msr_hi;

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