The scheduler's topology code uses rcu_assign_pointer() to initialize
various pointers.
Let us annotate the pointers correctly which also help avoid future
bugs. This suppresses the new sparse errors caused by an annotation
check I added to rcu_assign_pointer().
Also replace rcu_assign_pointer call on rq->sd with WRITE_ONCE. This
should be sufficient for the rq->sd initialization.
This fixes sparse errors:
kernel//sched/topology.c:378:9: sparse: error: incompatible types in
comparison expression (different address spaces)
kernel//sched/topology.c:387:9: sparse: error: incompatible types in
comparison expression (different address spaces)
kernel//sched/topology.c:612:9: sparse: error: incompatible types in
comparison expression (different address spaces)
kernel//sched/topology.c:615:9: sparse: error: incompatible types in
comparison expression (different address spaces)
kernel//sched/topology.c:618:9: sparse: error: incompatible types in
comparison expression (different address spaces)
kernel//sched/topology.c:621:9: sparse: error: incompatible types in
comparison expression (different address spaces)
Signed-off-by: Joel Fernandes (Google) <joel@xxxxxxxxxxxxxxxxx>
---
kernel/sched/sched.h | 12 ++++++------
kernel/sched/topology.c | 12 ++++++------
2 files changed, 12 insertions(+), 12 deletions(-)
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 2ab545d40381..806703afd4b0 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -780,7 +780,7 @@ struct root_domain {
* NULL-terminated list of performance domains intersecting with the
* CPUs of the rd. Protected by RCU.
*/
- struct perf_domain *pd;
+ struct perf_domain __rcu *pd;
};
extern struct root_domain def_root_domain;
@@ -1305,13 +1305,13 @@ static inline struct sched_domain *lowest_flag_domain(int cpu, int flag)
return sd;
}
-DECLARE_PER_CPU(struct sched_domain *, sd_llc);
+DECLARE_PER_CPU(struct sched_domain __rcu *, sd_llc);
DECLARE_PER_CPU(int, sd_llc_size);
DECLARE_PER_CPU(int, sd_llc_id);
-DECLARE_PER_CPU(struct sched_domain_shared *, sd_llc_shared);
-DECLARE_PER_CPU(struct sched_domain *, sd_numa);
-DECLARE_PER_CPU(struct sched_domain *, sd_asym_packing);
-DECLARE_PER_CPU(struct sched_domain *, sd_asym_cpucapacity);
+DECLARE_PER_CPU(struct sched_domain_shared __rcu *, sd_llc_shared);
+DECLARE_PER_CPU(struct sched_domain __rcu *, sd_numa);
+DECLARE_PER_CPU(struct sched_domain __rcu *, sd_asym_packing);
+DECLARE_PER_CPU(struct sched_domain __rcu *, sd_asym_cpucapacity);
extern struct static_key_false sched_asym_cpucapacity;
struct sched_group_capacity {
diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
index 3f35ba1d8fde..2eab2e16ded5 100644
--- a/kernel/sched/topology.c
+++ b/kernel/sched/topology.c
@@ -586,13 +586,13 @@ static void destroy_sched_domains(struct sched_domain *sd)
* the cpumask of the domain), this allows us to quickly tell if
* two CPUs are in the same cache domain, see cpus_share_cache().
*/
-DEFINE_PER_CPU(struct sched_domain *, sd_llc);
+DEFINE_PER_CPU(struct sched_domain __rcu *, sd_llc);
DEFINE_PER_CPU(int, sd_llc_size);
DEFINE_PER_CPU(int, sd_llc_id);
-DEFINE_PER_CPU(struct sched_domain_shared *, sd_llc_shared);
-DEFINE_PER_CPU(struct sched_domain *, sd_numa);
-DEFINE_PER_CPU(struct sched_domain *, sd_asym_packing);
-DEFINE_PER_CPU(struct sched_domain *, sd_asym_cpucapacity);
+DEFINE_PER_CPU(struct sched_domain_shared __rcu *, sd_llc_shared);
+DEFINE_PER_CPU(struct sched_domain __rcu *, sd_numa);
+DEFINE_PER_CPU(struct sched_domain __rcu *, sd_asym_packing);
+DEFINE_PER_CPU(struct sched_domain __rcu *, sd_asym_cpucapacity);
DEFINE_STATIC_KEY_FALSE(sched_asym_cpucapacity);
static void update_top_cache_domain(int cpu)
@@ -668,7 +668,7 @@ cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu)
rq_attach_root(rq, rd);
tmp = rq->sd;
- rcu_assign_pointer(rq->sd, sd);
+ WRITE_ONCE(rq->sd, sd);
dirty_sched_domain_sysctl(cpu);
destroy_sched_domains(tmp);
--
2.21.0.rc0.258.g878e2cd30e-goog
|