mirror of
https://github.com/mborgerson/xemu.git
synced 2026-04-27 04:33:21 +00:00
67da1dc5ce
Drivers can have internal request sources that generate IO, like the need_check_timer in QED. Since we want quiesced periods that contain nested event loops in block layer, we need to have a way to disable such event sources. Block drivers must implement the "bdrv_drain" callback if it has any internal sources that can generate I/O activity, like a timer or a worker thread (even in a library) that can schedule QEMUBH in an asynchronous callback. Update the comments of bdrv_drain and bdrv_drained_begin accordingly. Like bdrv_requests_pending(), we should consider all the children of bs. Before, the while loop just works, as bdrv_requests_pending() already tracks its children; now we mustn't miss the callback, so recurse down explicitly. Signed-off-by: Fam Zheng <famz@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Message-id: 1447064214-29930-9-git-send-email-famz@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>