From b88651cb4d4fa416fdbb6afaf5b26ec8c035eaad Mon Sep 17 00:00:00 2001 From: Leonardo Bras Date: Fri, 13 May 2022 03:28:31 -0300 Subject: QIOChannel: Add flags on io_writev and introduce io_flush callback Add flags to io_writev and introduce io_flush as optional callback to QIOChannelClass, allowing the implementation of zero copy writes by subclasses. How to use them: - Write data using qio_channel_writev*(...,QIO_CHANNEL_WRITE_FLAG_ZERO_COPY), - Wait write completion with qio_channel_flush(). Notes: As some zero copy write implementations work asynchronously, it's recommended to keep the write buffer untouched until the return of qio_channel_flush(), to avoid the risk of sending an updated buffer instead of the buffer state during write. As io_flush callback is optional, if a subclass does not implement it, then: - io_flush will return 0 without changing anything. Also, some functions like qio_channel_writev_full_all() were adapted to receive a flag parameter. That allows shared code between zero copy and non-zero copy writev, and also an easier implementation on new flags. Signed-off-by: Leonardo Bras Reviewed-by: Daniel P. Berrangé Reviewed-by: Peter Xu Reviewed-by: Juan Quintela Message-Id: <20220513062836.965425-3-leobras@redhat.com> Signed-off-by: Dr. David Alan Gilbert --- io/channel-file.c | 1 + 1 file changed, 1 insertion(+) (limited to 'io/channel-file.c') diff --git a/io/channel-file.c b/io/channel-file.c index d146ace7db..b67687c2aa 100644 --- a/io/channel-file.c +++ b/io/channel-file.c @@ -114,6 +114,7 @@ static ssize_t qio_channel_file_writev(QIOChannel *ioc, size_t niov, int *fds, size_t nfds, + int flags, Error **errp) { QIOChannelFile *fioc = QIO_CHANNEL_FILE(ioc); -- cgit v1.2.3-55-g7522