kvm: avoid unused variable warning for UP builds

The uniprocessor version of smp_call_function_many does not evaluate
all of its argument, and the compiler emits a warning about "wait"
being unused.  This breaks the build on architectures for which
"-Werror" is enabled by default.

Work around it by moving the invocation of smp_call_function_many to
its own inline function.

Reported-by: Paul Mackerras <paulus@ozlabs.org>
Cc: stable@vger.kernel.org
Fixes: 7a97cec26b94c909f4cbad2dc3186af3e457a522
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 19f0ecb..0d796c9 100644 (file)
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -187,12 +187,23 @@ static void ack_flush(void *_completed)
 {
 }
 
+static inline bool kvm_kick_many_cpus(const struct cpumask *cpus, bool wait)
+{
+       if (unlikely(!cpus))
+               cpus = cpu_online_mask;
+
+       if (cpumask_empty(cpus))
+               return false;
+
+       smp_call_function_many(cpus, ack_flush, NULL, wait);
+       return true;
+}
+
 bool kvm_make_all_cpus_request(struct kvm *kvm, unsigned int req)
 {
        int i, cpu, me;
        cpumask_var_t cpus;
-       bool called = true;
-       bool wait = req & KVM_REQUEST_WAIT;
+       bool called;
        struct kvm_vcpu *vcpu;
 
        zalloc_cpumask_var(&cpus, GFP_ATOMIC);
@@ -207,14 +218,9 @@ bool kvm_make_all_cpus_request(struct kvm *kvm, unsigned int req)
 
                if (cpus != NULL && cpu != -1 && cpu != me &&
                    kvm_request_needs_ipi(vcpu, req))
-                       cpumask_set_cpu(cpu, cpus);
+                       __cpumask_set_cpu(cpu, cpus);
        }
-       if (unlikely(cpus == NULL))
-               smp_call_function_many(cpu_online_mask, ack_flush, NULL, wait);
-       else if (!cpumask_empty(cpus))
-               smp_call_function_many(cpus, ack_flush, NULL, wait);
-       else
-               called = false;
+       called = kvm_kick_many_cpus(cpus, !!(req & KVM_REQUEST_WAIT));
        put_cpu();
        free_cpumask_var(cpus);
        return called;