[PATCH v9 1/8] sched/topology: Adding function partition_sched_domains_locked()

[Juri Lelli]

From: Mathieu Poirier <mathieu.poir...@linaro.org>

Introducing function partition_sched_domains_locked() by taking
the mutex locking code out of the original function.  That way
the work done by partition_sched_domains_locked() can be reused
without dropping the mutex lock.

No change of functionality is introduced by this patch.

Signed-off-by: Mathieu Poirier <mathieu.poir...@linaro.org>
Acked-by: Tejun Heo <t...@kernel.org>
---
 include/linux/sched/topology.h | 10 ++++++++++
 kernel/sched/topology.c        | 17 +++++++++++++----
 2 files changed, 23 insertions(+), 4 deletions(-)

diff --git a/include/linux/sched/topology.h b/include/linux/sched/topology.h
index cfc0a89a7159..d7166f8c0215 100644
--- a/include/linux/sched/topology.h
+++ b/include/linux/sched/topology.h
@@ -161,6 +161,10 @@ static inline struct cpumask *sched_domain_span(struct 
sched_domain *sd)
        return to_cpumask(sd->span);
 }
 
+extern void partition_sched_domains_locked(int ndoms_new,
+                                          cpumask_var_t doms_new[],
+                                          struct sched_domain_attr *dattr_new);
+
 extern void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
                                    struct sched_domain_attr *dattr_new);
 
@@ -213,6 +217,12 @@ unsigned long arch_scale_cpu_capacity(struct sched_domain 
*sd, int cpu)
 
 struct sched_domain_attr;
 
+static inline void
+partition_sched_domains_locked(int ndoms_new, cpumask_var_t doms_new[],
+                              struct sched_domain_attr *dattr_new)
+{
+}
+
 static inline void
 partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
                        struct sched_domain_attr *dattr_new)
diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
index f53f89df837d..362c383ec4bd 100644
--- a/kernel/sched/topology.c
+++ b/kernel/sched/topology.c
@@ -2159,16 +2159,16 @@ static int dattrs_equal(struct sched_domain_attr *cur, 
int idx_cur,
  * ndoms_new == 0 is a special case for destroying existing domains,
  * and it will not create the default domain.
  *
- * Call with hotplug lock held
+ * Call with hotplug lock and sched_domains_mutex held
  */
-void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
-                            struct sched_domain_attr *dattr_new)
+void partition_sched_domains_locked(int ndoms_new, cpumask_var_t doms_new[],
+                                   struct sched_domain_attr *dattr_new)
 {
        bool __maybe_unused has_eas = false;
        int i, j, n;
        int new_topology;
 
-       mutex_lock(&sched_domains_mutex);
+       lockdep_assert_held(&sched_domains_mutex);
 
        /* Always unregister in case we don't destroy any domains: */
        unregister_sched_domain_sysctl();
@@ -2251,6 +2251,15 @@ void partition_sched_domains(int ndoms_new, 
cpumask_var_t doms_new[],
        ndoms_cur = ndoms_new;
 
        register_sched_domain_sysctl();
+}
 
+/*
+ * Call with hotplug lock held
+ */
+void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
+                            struct sched_domain_attr *dattr_new)
+{
+       mutex_lock(&sched_domains_mutex);
+       partition_sched_domains_locked(ndoms_new, doms_new, dattr_new);
        mutex_unlock(&sched_domains_mutex);
 }
-- 
2.17.2