queue: add QTAILQ_REMOVE_SEVERAL

This is faster than removing elements one by one.

Will gain a user soon.

Signed-off-by: Emilio G. Cota <cota@braap.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

include/qemu/queue.h

@@ -420,6 +420,16 @@ union {                                                                 \
         (elm)->field.tqe_circ.tql_prev = NULL;                          \
 } while (/*CONSTCOND*/0)
 
+/* remove @left, @right and all elements in between from @head */
+#define QTAILQ_REMOVE_SEVERAL(head, left, right, field) do {            \
+        if (((right)->field.tqe_next) != NULL)                          \
+            (right)->field.tqe_next->field.tqe_circ.tql_prev =          \
+                (left)->field.tqe_circ.tql_prev;                        \
+        else                                                            \
+            (head)->tqh_circ.tql_prev = (left)->field.tqe_circ.tql_prev; \
+        (left)->field.tqe_circ.tql_prev->tql_next = (right)->field.tqe_next; \
+    } while (/*CONSTCOND*/0)
+
 #define QTAILQ_FOREACH(var, head, field)                                \
         for ((var) = ((head)->tqh_first);                               \
                 (var);                                                  \