KVM: introduce KVM_ERR_PTR_BAD_PAGE

It is used to eliminate the overload of function call and cleanup
the code

Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index e2dcc7c..ce7c329 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -68,6 +68,13 @@
 	return !is_noslot_pfn(pfn) && is_error_pfn(pfn);
 }
 
+#define KVM_ERR_PTR_BAD_PAGE	(ERR_PTR(-ENOENT))
+
+static inline int is_error_page(struct page *page)
+{
+	return IS_ERR(page);
+}
+
 /*
  * vcpu->requests bit members
  */
@@ -409,7 +416,6 @@
 	return slot;
 }
 
-int is_error_page(struct page *page);
 int kvm_is_error_hva(unsigned long addr);
 int kvm_set_memory_region(struct kvm *kvm,
 			  struct kvm_userspace_memory_region *mem,
@@ -436,7 +442,6 @@
 int gfn_to_page_many_atomic(struct kvm *kvm, gfn_t gfn, struct page **pages,
 			    int nr_pages);
 
-struct page *get_bad_page(void);
 struct page *gfn_to_page(struct kvm *kvm, gfn_t gfn);
 unsigned long gfn_to_hva(struct kvm *kvm, gfn_t gfn);
 void kvm_release_page_clean(struct page *page);