block: introduce bdrv_no_throttling_begin/end

Extract the handling of throttling from bdrv_flush_io_queue.  These
new functions will soon become BdrvChildRole callbacks, as they can
be generalized to "beginning of drain" and "end of drain".

Reviewed-by: Alberto Garcia <berto@igalia.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/block/throttle-groups.c b/block/throttle-groups.c
index b796f6b9fa..9ac063a0cd 100644
--- a/block/throttle-groups.c
+++ b/block/throttle-groups.c
@@ -219,6 +219,10 @@ static bool throttle_group_schedule_timer(BlockDriverState *bs,
     ThrottleGroup *tg = container_of(ts, ThrottleGroup, ts);
     bool must_wait;
 
+    if (bs->io_limits_disabled) {
+        return false;
+    }
+
     /* Check if any of the timers in this group is already armed */
     if (tg->any_timer_armed[is_write]) {
         return true;