[PATCH] sched/core: dl_bw_of() has to be used under rcu_read_lock_sched()

Juri Lelli
2014-10-28T11:54:58Z

As per commit f10e00f4bf36 ("sched/dl: Use dl_bw_of() under
rcu_read_lock_sched()"), dl_bw_of() has to be protected by
rcu_read_lock_sched().

Signed-off-by: Juri Lelli <juri.lelli@arm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org
---
kernel/sched/core.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index b9f78f1..b9fb426 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -4657,6 +4657,7 @@ int cpuset_cpumask_can_shrink(const struct cpumask *cur,
struct dl_bw *cur_dl_b;
unsigned long flags;

+ rcu_read_lock_sched();
cur_dl_b = dl_bw_of(cpumask_any(cur));
trial_cpus = cpumask_weight(trial);

@@ -4665,6 +4666,7 @@ int cpuset_cpumask_can_shrink(const struct cpumask *cur,
cur_dl_b->bw * trial_cpus < cur_dl_b->total_bw)
ret = 0;
raw_spin_unlock_irqrestore(&cur_dl_b->lock, flags);
+ rcu_read_unlock_sched();

return ret;
}
@@ -4693,11 +4695,13 @@ int task_can_attach(struct task_struct *p,
cs_cpus_allowed)) {
unsigned int dest_cpu = cpumask_any_and(cpu_active_mask,
cs_cpus_allowed);
- struct dl_bw *dl_b = dl_bw_of(dest_cpu);
+ struct dl_bw *dl_b;
bool overflow;
int cpus;
unsigned long flags;

+ rcu_read_lock_sched();
+ dl_b = dl_bw_of(dest_cpu);
raw_spin_lock_irqsave(&dl_b->lock, flags);
cpus = dl_bw_cpus(dest_cpu);
overflow = __dl_overflow(dl_b, cpus, 0, p->dl.dl_bw);
@@ -4713,6 +4717,7 @@ int task_can_attach(struct task_struct *p,
__dl_add(dl_b, p->dl.dl_bw);
}
raw_spin_unlock_irqrestore(&dl_b->lock, flags);
+ rcu_read_unlock_sched();

}
#endif
--
2.1.2