On Fri, Oct 28, 2022 at 01:39:08PM +0300, Nikolay Borisov wrote:
> preadv is going to be needed when 'fixed-ram'-enabled stream are to be
> restored. Add a minimal implementation of preadv for file channels and
> expose it via the generic io_preadv interface.
>
> Signed-off-by: Nikolay Borisov <nbori...@suse.com>
> ---
> io/channel-file.c | 27 +++++++++++++++++++++++++++
> 1 file changed, 27 insertions(+)
>
> diff --git a/io/channel-file.c b/io/channel-file.c
> index e213a0fd7cd2..d2f4706b7f6d 100644
> --- a/io/channel-file.c
> +++ b/io/channel-file.c
> @@ -145,6 +145,32 @@ static ssize_t qio_channel_file_writev(QIOChannel *ioc,
> return ret;
> }
>
> +static ssize_t qio_channel_file_preadv(QIOChannel *ioc,
> + const struct iovec *iov,
> + size_t niov,
> + off_t offset,
> + Error **errp)
> +{
> + QIOChannelFile *fioc = QIO_CHANNEL_FILE(ioc);
> + ssize_t ret;
> +
> + retry:
> + ret = preadv(fioc->fd, iov, niov, offset);
> + if (ret < 0) {
> + if (errno == EAGAIN) {
> + return QIO_CHANNEL_ERR_BLOCK;
> + }
> + if (errno == EINTR) {
> + goto retry;
> + }
> +
> + error_setg_errno(errp, errno, "Unable to read from file");
> + return -1;
> + }
> +
> + return ret;
> +}
> +
> static ssize_t qio_channel_file_pwritev(QIOChannel *ioc,
> const struct iovec *iov,
> size_t niov,
> @@ -252,6 +278,7 @@ static void qio_channel_file_class_init(ObjectClass
> *klass,
> ioc_klass->io_readv = qio_channel_file_readv;
> ioc_klass->io_set_blocking = qio_channel_file_set_blocking;
> ioc_klass->io_pwritev = qio_channel_file_pwritev;
> + ioc_klass->io_preadv = qio_channel_file_preadv;
> ioc_klass->io_seek = qio_channel_file_seek;
> ioc_klass->io_close = qio_channel_file_close;
> ioc_klass->io_create_watch = qio_channel_file_create_watch;
I'd suggest this patch should just be merged into the patch which
adds the io_pwritev callback.
With regards,
Daniel
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