[PATCH v3 05/12] KVM: selftests: Extract picking of random CPU from cpu_set_t to separate API

[Sean Christopherson <seanjc@google.com>]

Extract kvm_pick_random_cpu() out of pin_task_to_random_cpu() so that tests
can choose a random CPU without having to immediately pin a task to that
CPU.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 tools/testing/selftests/kvm/include/kvm_util.h | 11 ++++++++++-
 tools/testing/selftests/kvm/lib/kvm_util.c     |  7 ++-----
 2 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/tools/testing/selftests/kvm/include/kvm_util.h b/tools/testing/selftests/kvm/include/kvm_util.h
index 61d72e1e7601..5a7a455b5387 100644
--- a/tools/testing/selftests/kvm/include/kvm_util.h
+++ b/tools/testing/selftests/kvm/include/kvm_util.h
@@ -1084,6 +1084,8 @@ struct kvm_vcpu *vm_recreate_with_one_vcpu(struct kvm_vm *vm);
 
 void kvm_set_files_rlimit(u32 nr_vcpus);
 
+int kvm_pick_random_cpu(cpu_set_t *possible_cpus);
+
 int __pin_task_to_cpu(pthread_t task, int cpu);
 
 static inline void pin_task_to_cpu(pthread_t task, int cpu)
@@ -1094,7 +1096,14 @@ static inline void pin_task_to_cpu(pthread_t task, int cpu)
 	TEST_ASSERT(!r, "Failed to set thread affinity to pCPU '%u'", cpu);
 }
 
-int pin_task_to_random_cpu(pthread_t task, cpu_set_t *possible_cpus);
+static inline int pin_task_to_random_cpu(pthread_t task, cpu_set_t *possible_cpus)
+{
+	int cpu;
+
+	cpu = kvm_pick_random_cpu(possible_cpus);
+	pin_task_to_cpu(task, cpu);
+	return cpu;
+}
 
 static inline int pin_task_to_any_cpu(pthread_t task)
 {
diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
index af2bad0553f9..9ddc047d5c27 100644
--- a/tools/testing/selftests/kvm/lib/kvm_util.c
+++ b/tools/testing/selftests/kvm/lib/kvm_util.c
@@ -668,7 +668,7 @@ void kvm_print_vcpu_pinning_help(void)
 	       "     (default: no pinning)\n", name, name);
 }
 
-int pin_task_to_random_cpu(pthread_t task, cpu_set_t *possible_cpus)
+int kvm_pick_random_cpu(cpu_set_t *possible_cpus)
 {
 	int target_idx;
 	int nr_cpus;
@@ -680,12 +680,9 @@ int pin_task_to_random_cpu(pthread_t task, cpu_set_t *possible_cpus)
 	target_idx = kvm_random_u64(&kvm_rng) % nr_cpus;
 
 	for (cpu = 0; cpu < CPU_SETSIZE; cpu++) {
-		if (CPU_ISSET(cpu, possible_cpus) && target_idx-- == 0) {
-			pin_task_to_cpu(task, cpu);
+		if (CPU_ISSET(cpu, possible_cpus) && target_idx-- == 0)
 			return cpu;
-		}
 	}
-
 	TEST_FAIL("Failed to find random CPU in possible_cpus");
 	return -1;
 }
-- 
2.55.0.508.g3f0d502094-goog