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Subject[PATCH v2] sched/deadline: Use unsigned type for the state flags
Commit

799ba82de01e ("sched/deadline: Use C bitfields for the state flags")

converted state flags into one-bit signed int. Signed one-bit type can be
either 0 or -1, which is going to cause a problem once 1 is assigned to
it and then the value later tested against 1.

The current code is okay, as all the checks are (non-)zero check, but I believe
that we'd rather be safe than sorry here; remove the fragility by converting
the state flags to unsigned int, where 1 actually really is 1.

This also silences annoying sparse complaints about this very issue when
compiling any code that includes sched.h.

Fixes: 799ba82de01e ("sched/deadline: Use C bitfields for the state flags")
Cc: luca abeni <luca.abeni@santannapisa.it>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Daniel Bristot de Oliveira <bristot@redhat.com>
Cc: Juri Lelli <juri.lelli@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
---

v2: switch over to unsisgned int from bool, as asked for by Thomas. Feel
free to pick either of the versions

include/linux/sched.h | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/include/linux/sched.h b/include/linux/sched.h
index a5dc7c98b0a2..b634da8a35a3 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -473,10 +473,10 @@ struct sched_dl_entity {
* conditions between the inactive timer handler and the wakeup
* code.
*/
- int dl_throttled : 1;
- int dl_boosted : 1;
- int dl_yielded : 1;
- int dl_non_contending : 1;
+ unsigned int dl_throttled : 1;
+ unsigned int dl_boosted : 1;
+ unsigned int dl_yielded : 1;
+ unsigned int dl_non_contending : 1;

/*
* Bandwidth enforcement timer. Each -deadline task has its
--
Jiri Kosina
SUSE Labs
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