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Also, try_cmpxchg() implicitly assigns old *ptr value to "old" when cmpxchg fails, enabling substantial source code simplifications. No functional change intended. Signed-off-by: Uros Bizjak Cc: Ingo Molnar Cc: Peter Zijlstra Cc: Juri Lelli Cc: Vincent Guittot Cc: Dietmar Eggemann Cc: Steven Rostedt Cc: Ben Segall Cc: Mel Gorman Cc: Valentin Schneider --- kernel/sched/sched.h | 15 +++++---------- 1 file changed, 5 insertions(+), 10 deletions(-) diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 83e3aa917142..42006e8525c9 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -3647,21 +3647,16 @@ static inline void mm_cid_put_lazy(struct task_stru= ct *t) static inline int mm_cid_pcpu_unset(struct mm_struct *mm) { struct mm_cid __percpu *pcpu_cid =3D mm->pcpu_cid; - int cid, res; + int cid; =20 lockdep_assert_irqs_disabled(); cid =3D __this_cpu_read(pcpu_cid->cid); - for (;;) { + do { if (mm_cid_is_unset(cid)) return MM_CID_UNSET; - /* - * Attempt transition from valid or lazy-put to unset. - */ - res =3D cmpxchg(&this_cpu_ptr(pcpu_cid)->cid, cid, MM_CID_UNSET); - if (res =3D=3D cid) - break; - cid =3D res; - } + /* Attempt transition from valid or lazy-put to unset. */ + } while (!try_cmpxchg(&this_cpu_ptr(pcpu_cid)->cid, &cid, MM_CID_UNSET)); + return cid; } =20 --=20 2.50.1