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Subject[PATCH v2] sched/uclamp: Fix overzealous type replacement
Date
Some uclamp helpers had their return type changed from 'unsigned int' to
'enum uclamp_id' by commit

0413d7f33e60 ("sched/uclamp: Always use 'enum uclamp_id' for clamp_id values")

but it happens that some do return a value in the [0, SCHED_CAPACITY_SCALE]
range, which should really be unsigned int. The affected helpers are
uclamp_none(), uclamp_rq_max_value() and uclamp_eff_value(). Fix those up.

Note that this doesn't lead to any obj diff using a relatively recent
aarch64 compiler (8.3-2019.03). The current code of e.g. uclamp_eff_value()
properly returns an 11 bit value (bits_per(1024)) and doesn't seem to do
anything funny. I'm still marking this as fixing the above commit to be on
the safe side.

Fixes: 0413d7f33e60 ("sched/uclamp: Always use 'enum uclamp_id' for clamp_id values")
Reviewed-by: Qais Yousef <qais.yousef@arm.com>
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
---
v2 changes:
o Also fix uclamp_none() (Vincent)
o Collect reviewed-by
o Slightly reword changelog
---
kernel/sched/core.c | 6 +++---
kernel/sched/sched.h | 2 +-
2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 513a4794ff36..3ceff1c93ef1 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -810,7 +810,7 @@ static inline unsigned int uclamp_bucket_base_value(unsigned int clamp_value)
return UCLAMP_BUCKET_DELTA * uclamp_bucket_id(clamp_value);
}

-static inline enum uclamp_id uclamp_none(enum uclamp_id clamp_id)
+static inline unsigned int uclamp_none(enum uclamp_id clamp_id)
{
if (clamp_id == UCLAMP_MIN)
return 0;
@@ -853,7 +853,7 @@ static inline void uclamp_idle_reset(struct rq *rq, enum uclamp_id clamp_id,
}

static inline
-enum uclamp_id uclamp_rq_max_value(struct rq *rq, enum uclamp_id clamp_id,
+unsigned int uclamp_rq_max_value(struct rq *rq, enum uclamp_id clamp_id,
unsigned int clamp_value)
{
struct uclamp_bucket *bucket = rq->uclamp[clamp_id].bucket;
@@ -918,7 +918,7 @@ uclamp_eff_get(struct task_struct *p, enum uclamp_id clamp_id)
return uc_req;
}

-enum uclamp_id uclamp_eff_value(struct task_struct *p, enum uclamp_id clamp_id)
+unsigned int uclamp_eff_value(struct task_struct *p, enum uclamp_id clamp_id)
{
struct uclamp_se uc_eff;

diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 05c282775f21..280a3c735935 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -2300,7 +2300,7 @@ static inline void cpufreq_update_util(struct rq *rq, unsigned int flags) {}
#endif /* CONFIG_CPU_FREQ */

#ifdef CONFIG_UCLAMP_TASK
-enum uclamp_id uclamp_eff_value(struct task_struct *p, enum uclamp_id clamp_id);
+unsigned int uclamp_eff_value(struct task_struct *p, enum uclamp_id clamp_id);

static __always_inline
unsigned int uclamp_util_with(struct rq *rq, unsigned int util,
--
2.22.0
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