rangeset: add rangeset_purge() function

This function can be used when user wants to remove all rangeset
entries but do not want to destroy rangeset itself.

Signed-off-by: Volodymyr Babchuk <volodymyr_babchuk@epam.com>
Signed-off-by: Stewart Hildebrand <stewart.hildebrand@amd.com>
Acked-by: Jan Beulich <jbeulich@suse.com>

xen/common/rangeset.c

@@ -448,11 +448,20 @@ struct rangeset *rangeset_new(
     return r;
 }
 
-void rangeset_destroy(
-    struct rangeset *r)
+void rangeset_purge(struct rangeset *r)
 {
     struct range *x;
 
+    if ( r == NULL )
+        return;
+
+    while ( (x = first_range(r)) != NULL )
+        destroy_range(r, x);
+}
+
+void rangeset_destroy(
+    struct rangeset *r)
+{
     if ( r == NULL )
         return;
 
@@ -463,8 +472,7 @@ void rangeset_destroy(
         spin_unlock(&r->domain->rangesets_lock);
     }
 
-    while ( (x = first_range(r)) != NULL )
-        destroy_range(r, x);
+    rangeset_purge(r);
 
     xfree(r);
 }

xen/include/xen/rangeset.h

@@ -56,7 +56,7 @@ void rangeset_limit(
 bool __must_check rangeset_is_empty(
     const struct rangeset *r);
 
-/* Add/claim/remove/query a numeric range. */
+/* Add/claim/remove/query/purge a numeric range. */
 int __must_check rangeset_add_range(
     struct rangeset *r, unsigned long s, unsigned long e);
 int __must_check rangeset_claim_range(struct rangeset *r, unsigned long size,
@@ -70,6 +70,7 @@ bool __must_check rangeset_overlaps_range(
 int rangeset_report_ranges(
     struct rangeset *r, unsigned long s, unsigned long e,
     int (*cb)(unsigned long s, unsigned long e, void *data), void *ctxt);
+void rangeset_purge(struct rangeset *r);
 
 /*
  * Note that the consume function can return an error value apart from