percpu: Resolve ambiguities in __get_cpu_var/cpumask_var_t

__get_cpu_var can paper over differences in the definitions of
cpumask_var_t and either use the address of the cpumask variable
directly or perform a fetch of the address of the struct cpumask
allocated elsewhere. This is important particularly when using per cpu
cpumask_var_t declarations because in one case we have an offset into
a per cpu area to handle and in the other case we need to fetch a
pointer from the offset.

This patch introduces a new macro

this_cpu_cpumask_var_ptr()

that is defined where cpumask_var_t is defined and performs the proper
actions. All use cases where __get_cpu_var is used with cpumask_var_t
are converted to the use of this_cpu_cpumask_var_ptr().

Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

3 files changed, 3 insertions, 3 deletions

diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index 255ce138b652..4a608cfaecbd 100644
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -1158,7 +1158,7 @@ static DEFINE_PER_CPU(cpumask_var_t, local_cpu_mask_dl);
 static int find_later_rq(struct task_struct *task)
 {
         struct sched_domain *sd;
-        struct cpumask *later_mask = __get_cpu_var(local_cpu_mask_dl);
+        struct cpumask *later_mask = this_cpu_cpumask_var_ptr(local_cpu_mask_dl);
         int this_cpu = smp_processor_id();
         int best_cpu, cpu = task_cpu(task);
 
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index bfa3c86d0d68..197d659c144c 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -6539,7 +6539,7 @@ static int load_balance(int this_cpu, struct rq *this_rq,
         struct sched_group *group;
         struct rq *busiest;
         unsigned long flags;
-        struct cpumask *cpus = __get_cpu_var(load_balance_mask);
+        struct cpumask *cpus = this_cpu_cpumask_var_ptr(load_balance_mask);
 
         struct lb_env env = {
                 .sd             = sd,
diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
index 5f6edca4fafd..a4c50fce9b90 100644
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -1526,7 +1526,7 @@ static DEFINE_PER_CPU(cpumask_var_t, local_cpu_mask);
 static int find_lowest_rq(struct task_struct *task)
 {
         struct sched_domain *sd;
-        struct cpumask *lowest_mask = __get_cpu_var(local_cpu_mask);
+        struct cpumask *lowest_mask = this_cpu_cpumask_var_ptr(local_cpu_mask);
         int this_cpu = smp_processor_id();
         int cpu      = task_cpu(task);