linux-kernel - [PATCH RFC] sched: fix function declaration return type mismatch

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Date:	Fri, 15 May 2015 21:05:42 +0200
From:	Nicholas Mc Guire <hofrat@...dl.org>
To:	Ingo Molnar <mingo@...hat.com>
Cc:	Peter Zijlstra <peterz@...radead.org>,
	linux-kernel@...r.kernel.org, Nicholas Mc Guire <hofrat@...dl.org>
Subject: [PATCH RFC] sched: fix function declaration return type mismatch

static code checking was unhappy with
./kernel/sched/fair.c:162 WARNING: return of wrong type
                int != unsigned int

get_update_sysctl_factor() is declared to return int but is currently 
returning an unsigned int. The first few preprocessed lines are:

 static int get_update_sysctl_factor(void)
 {
 unsigned int cpus = ({ int __min1 = (cpumask_weight(cpu_online_mask));
int __min2 = (8); __min1 < __min2 ? __min1: __min2; });
 unsigned int factor;

min_t should be unsigned int and return type of get_update_sysctl_factor
also unsigned int as its call-site update_sysctl() is expecting unsigned
int and the values utilizing factor sysctl_sched_min_granularity ,
sched_nr_latency and sysctl_sched_wakeup_granularity are also unsigned int
(and cpumask_weight also is returning unsigned int).

Patch was compile tested with x86_64_defconfig + CONFIG_SCHED_DEBUG=y
and changed sections in kernel/sched/fair.i reviewed.

Patch is against 4.1-rc3 (localversion-next is -next-20150514)

Signed-off-by: Nicholas Mc Guire <hofrat@...dl.org>
---
 kernel/sched/fair.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 8c1510a..a9895b0 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -141,9 +141,9 @@ static inline void update_load_set(struct load_weight *lw, unsigned long w)
  *
  * This idea comes from the SD scheduler of Con Kolivas:
  */
-static int get_update_sysctl_factor(void)
+static unsigned int get_update_sysctl_factor(void)
 {
-	unsigned int cpus = min_t(int, num_online_cpus(), 8);
+	unsigned int cpus = min_t(unsigned int, num_online_cpus(), 8);
 	unsigned int factor;
 
 	switch (sysctl_sched_tunable_scaling) {
@@ -576,7 +576,7 @@ int sched_proc_update_handler(struct ctl_table *table, int write,
 		loff_t *ppos)
 {
 	int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
-	int factor = get_update_sysctl_factor();
+	unsigned int factor = get_update_sysctl_factor();
 
 	if (ret || !write)
 		return ret;
-- 
1.7.10.4

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