Introduce gnttab_empty_grant_references() to check whether grant

references is empty.

Signed-off-by: Isaku Yamahata <yamahata@valinux.co.jp>

linux-2.6-xen-sparse/drivers/xen/core/gnttab.c

@@ -65,6 +65,7 @@ EXPORT_SYMBOL_GPL(gnttab_end_foreign_transfer);
 EXPORT_SYMBOL_GPL(gnttab_alloc_grant_references);
 EXPORT_SYMBOL_GPL(gnttab_free_grant_references);
 EXPORT_SYMBOL_GPL(gnttab_free_grant_reference);
+EXPORT_SYMBOL_GPL(gnttab_empty_grant_references);
 EXPORT_SYMBOL_GPL(gnttab_claim_grant_reference);
 EXPORT_SYMBOL_GPL(gnttab_release_grant_reference);
 EXPORT_SYMBOL_GPL(gnttab_request_free_callback);
@@ -324,6 +325,12 @@ gnttab_alloc_grant_references(u16 count, grant_ref_t *head)
 	return 0;
 }
 
+int
+gnttab_empty_grant_references(const grant_ref_t *private_head)
+{
+	return (*private_head == GNTTAB_LIST_END);
+}
+
 int
 gnttab_claim_grant_reference(grant_ref_t *private_head)
 {

linux-2.6-xen-sparse/include/xen/gnttab.h

@@ -91,6 +91,8 @@ void gnttab_free_grant_reference(grant_ref_t ref);
 
 void gnttab_free_grant_references(grant_ref_t head);
 
+int gnttab_empty_grant_references(const grant_ref_t *pprivate_head);
+
 int gnttab_claim_grant_reference(grant_ref_t *pprivate_head);
 
 void gnttab_release_grant_reference(grant_ref_t *private_head,