[tip:sched/core] sched: Fix function declaration return type mismatch

From: tip-bot for Nicholas Mc Guire
Date: Sun May 17 2015 - 02:01:47 EST


Commit-ID: 58ac93e4f2e4b15beffdf0e3749b7fea3208ef66
Gitweb: http://git.kernel.org/tip/58ac93e4f2e4b15beffdf0e3749b7fea3208ef66
Author: Nicholas Mc Guire <hofrat@xxxxxxxxx>
AuthorDate: Fri, 15 May 2015 21:05:42 +0200
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Sun, 17 May 2015 06:47:46 +0200

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;

The type used by min_t() should be 'unsigned int' and the return type
of get_update_sysctl_factor() should also be 'unsigned int' as its
call-site update_sysctl() is expecting 'unsigned int' and the values
utilizing:

'factor'
'sysctl_sched_min_granularity'
'sched_nr_latency'
'sysctl_sched_wakeup_granularity'

... are also all 'unsigned int', plus cpumask_weight() is also
returning 'unsigned int'.

So the natural type to use around here is 'unsigned int'.

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

Signed-off-by: Nicholas Mc Guire <hofrat@xxxxxxxxx>
[ Improved the changelog a bit. ]
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/1431716742-11077-1-git-send-email-hofrat@xxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
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 f18ddb7..a27d988 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;
--
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