Quite a while ago now, the majority of QEMUFile implementations were switched over to use QIOChannel APIs, but a couple remained.
The newish multifd code is directly using QIOChannel, only calling in to QEMUFile for the VMState transfer and for rate limiting purposes. This series finishes the job of converting QEMUFile to always have a QIOChannel as its backend, enabling a removal of QEMUFileOps. Most callers still need to use the QEMUFile APIs though, as that performs buffering of reads/writes. As a followup to this series, however, it would be practical to introduce a QIOChannelCache that layers on top of another QIOChannel to add buffering equivalent to what QEMUFile does, possibly with the rate limiting too. At that point QEMUFile would not really be doing much at all and could possibly go away entirely, leaving just the MigrationState object for global state tracking, managing one or more QIOChannel objects for the data transfer. I think this could simplify future evolution of migration code. I'm not likely to have time in the immediate future to work on such a followup though. Daniel P. Berrangé (20): io: add a QIOChannelNull equivalent to /dev/null migration: switch to use QIOChannelNull for dummy channel migration: remove unreachble RDMA code in save_hook impl migration: rename rate limiting fields in QEMUFile migration: rename 'pos' field in QEMUFile to 'bytes_processed' migration: rename qemu_ftell to qemu_file_total_transferred migration: rename qemu_update_position to qemu_file_credit_transfer migration: introduce a QIOChannel impl for BlockDriverState VMState migration: convert savevm to use QIOChannelBlock for VMState migration: stop passing 'opaque' parameter to QEMUFile hooks migration: hardcode assumption that QEMUFile is backed with QIOChannel migration: introduce new constructors for QEMUFile migration: remove unused QEMUFileGetFD typedef migration: remove the QEMUFileOps 'shut_down' callback migration: remove the QEMUFileOps 'set_blocking' callback migration: remove the QEMUFileOps 'close' callback migration: remove the QEMUFileOps 'get_buffer' callback migration: remove the QEMUFileOps 'writev_buffer' callback migration: remove the QEMUFileOps 'get_return_path' callback migration: remove the QEMUFileOps abstraction include/io/channel-null.h | 55 +++++++ io/channel-null.c | 237 ++++++++++++++++++++++++++++++ io/meson.build | 1 + io/trace-events | 3 + migration/block.c | 10 +- migration/channel-block.c | 195 ++++++++++++++++++++++++ migration/channel-block.h | 59 ++++++++ migration/channel.c | 4 +- migration/colo.c | 5 +- migration/meson.build | 2 +- migration/migration.c | 9 +- migration/qemu-file-channel.c | 194 ------------------------ migration/qemu-file-channel.h | 32 ---- migration/qemu-file.c | 188 +++++++++++++----------- migration/qemu-file.h | 122 +++++++-------- migration/ram.c | 8 +- migration/rdma.c | 144 +++++------------- migration/savevm.c | 55 ++----- migration/vmstate.c | 4 +- tests/unit/meson.build | 1 + tests/unit/test-io-channel-null.c | 95 ++++++++++++ tests/unit/test-vmstate.c | 5 +- 22 files changed, 870 insertions(+), 558 deletions(-) create mode 100644 include/io/channel-null.h create mode 100644 io/channel-null.c create mode 100644 migration/channel-block.c create mode 100644 migration/channel-block.h delete mode 100644 migration/qemu-file-channel.c delete mode 100644 migration/qemu-file-channel.h create mode 100644 tests/unit/test-io-channel-null.c -- 2.36.1
