KVM: x86/mmu: use tdp_mmu_free_sp to free roots

Minor cleanup to deduplicate the code used to free a struct kvm_mmu_page
in the TDP MMU.

No functional change intended.
Signed-off-by: Ben Gardon <bgardon@google.com>
Message-Id: <20210401233736.638171-4-bgardon@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/mmu/tdp_mmu.c

@@ -92,6 +92,12 @@ static inline struct kvm_mmu_page *tdp_mmu_next_root(struct kvm *kvm,
 static bool zap_gfn_range(struct kvm *kvm, struct kvm_mmu_page *root,
 			  gfn_t start, gfn_t end, bool can_yield, bool flush);
 
+static void tdp_mmu_free_sp(struct kvm_mmu_page *sp)
+{
+	free_page((unsigned long)sp->spt);
+	kmem_cache_free(mmu_page_header_cache, sp);
+}
+
 void kvm_tdp_mmu_free_root(struct kvm *kvm, struct kvm_mmu_page *root)
 {
 	gfn_t max_gfn = 1ULL << (shadow_phys_bits - PAGE_SHIFT);
@@ -105,8 +111,7 @@ void kvm_tdp_mmu_free_root(struct kvm *kvm, struct kvm_mmu_page *root)
 
 	zap_gfn_range(kvm, root, 0, max_gfn, false, false);
 
-	free_page((unsigned long)root->spt);
-	kmem_cache_free(mmu_page_header_cache, root);
+	tdp_mmu_free_sp(root);
 }
 
 static union kvm_mmu_page_role page_role_for_level(struct kvm_vcpu *vcpu,
@@ -168,12 +173,6 @@ hpa_t kvm_tdp_mmu_get_vcpu_root_hpa(struct kvm_vcpu *vcpu)
 	return __pa(root->spt);
 }
 
-static void tdp_mmu_free_sp(struct kvm_mmu_page *sp)
-{
-	free_page((unsigned long)sp->spt);
-	kmem_cache_free(mmu_page_header_cache, sp);
-}
-
 /*
  * This is called through call_rcu in order to free TDP page table memory
  * safely with respect to other kernel threads that may be operating on