Re: [Qemu-devel] [PATCH 01/16] qio: create new qio_channel_write_all

["Daniel P. Berrange" <berrange@redhat.com>]

On Mon, Mar 13, 2017 at 01:44:19PM +0100, Juan Quintela wrote:
> The function waits until it is able to write the full iov.
> 
> Signed-off-by: Juan Quintela <quintela@redhat.com>
> ---
>  include/io/channel.h          | 23 +++++++++++++++++++++++
>  io/channel.c                  | 39 +++++++++++++++++++++++++++++++++++++++
>  migration/qemu-file-channel.c | 29 +----------------------------
>  3 files changed, 63 insertions(+), 28 deletions(-)
> 
> diff --git a/include/io/channel.h b/include/io/channel.h
> index 5d48906..f786c4f 100644
> --- a/include/io/channel.h
> +++ b/include/io/channel.h
> @@ -269,6 +269,29 @@ ssize_t qio_channel_writev_full(QIOChannel *ioc,
>                                  Error **errp);
>  
>  /**
> + * qio_channel_writev_all:
> + * @ioc: the channel object
> + * @iov: the array of memory regions to write data from
> + * @niov: the length of the @iov array
> + * @errp: pointer to a NULL-initialized error object
> + *
> + * Write data to the IO channel, reading it from the
> + * memory regions referenced by @iov. Each element
> + * in the @iov will be fully sent, before the next
> + * one is used. The @niov parameter specifies the
> + * total number of elements in @iov.
> + *
> + * It is required for all @iov data to be fully
> + * sent.
> + *
> + * Returns: the number of bytes sent, or -1 on error,
> + */
> +ssize_t qio_channel_writev_all(QIOChannel *ioc,
> +                               const struct iovec *iov,
> +                               size_t niov,
> +                               Error **erp);
> +
> +/**
>   * qio_channel_readv:
>   * @ioc: the channel object
>   * @iov: the array of memory regions to read data into
> diff --git a/io/channel.c b/io/channel.c
> index cdf7454..c5a1bd5 100644
> --- a/io/channel.c
> +++ b/io/channel.c
> @@ -22,6 +22,7 @@
>  #include "io/channel.h"
>  #include "qapi/error.h"
>  #include "qemu/main-loop.h"
> +#include "qemu/iov.h"
>  
>  bool qio_channel_has_feature(QIOChannel *ioc,
>                               QIOChannelFeature feature)
> @@ -85,6 +86,44 @@ ssize_t qio_channel_writev_full(QIOChannel *ioc,
>  }
>  
>  
> +
> +ssize_t qio_channel_writev_all(QIOChannel *ioc,
> +                               const struct iovec *iov,
> +                               size_t niov,
> +                               Error **errp)
> +{
> +    ssize_t done = 0;
> +    struct iovec *local_iov = g_new(struct iovec, niov);
> +    struct iovec *local_iov_head = local_iov;
> +    unsigned int nlocal_iov = niov;
> +
> +    nlocal_iov = iov_copy(local_iov, nlocal_iov,
> +                          iov, niov,
> +                          0, iov_size(iov, niov));
> +
> +    while (nlocal_iov > 0) {
> +        ssize_t len;
> +        len = qio_channel_writev(ioc, local_iov, nlocal_iov, errp);
> +        if (len == QIO_CHANNEL_ERR_BLOCK) {
> +            qio_channel_wait(ioc, G_IO_OUT);
> +            continue;
> +        }
> +        if (len < 0) {
> +            error_setg_errno(errp, EIO,
> +                             "Channel was not able to write full iov");
> +            done = -1;
> +            goto cleanup;
> +        }
> +
> +        iov_discard_front(&local_iov, &nlocal_iov, len);
> +        done += len;
> +    }
> +
> + cleanup:
> +    g_free(local_iov_head);
> +    return done;
> +}
> +

Can you make sure this is covered in the test suite. Something added
or changed in tests/io-channel-helpers.c should be sufficient. eg use
it from test_io_thread_writer() when applicable


Regards,
Daniel
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