Re: [Qemu-devel] [PATCH 02/16] qio: create new qio_channel_read_all

[Daniel P. Berrange]

On Mon, Mar 13, 2017 at 01:44:20PM +0100, Juan Quintela wrote:
> It is the symmetric function from qio_channel_write_all
> 
> Signed-off-by: Juan Quintela <address@hidden>
> ---
>  include/io/channel.h | 23 +++++++++++++++++++++++
>  io/channel.c         | 37 +++++++++++++++++++++++++++++++++++++
>  2 files changed, 60 insertions(+)
> 
> diff --git a/include/io/channel.h b/include/io/channel.h
> index f786c4f..2f55831 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_readv_all:
> + * @ioc: the channel object
> + * @iov: the array of memory regions to read data into
> + * @niov: the length of the @iov array
> + * @errp: pointer to a NULL-initialized error object
> + *
> + * Read data from the IO channel, storing it in the
> + * memory regions referenced by @iov. Each element
> + * in the @iov will be fully populated with data
> + * before the next one is used. The @niov parameter
> + * specifies the total number of elements in @iov.
> + *
> + * Returns: the number of bytes read, or -1 on error,
> + * or QIO_CHANNEL_ERR_BLOCK if no data is available
> + * and the channel is non-blocking
> + */
> +ssize_t qio_channel_readv_all(QIOChannel *ioc,
> +                              const struct iovec *iov,
> +                              size_t niov,
> +                              Error **errp);
> +
> +
> +/**
>   * qio_channel_writev_all:
>   * @ioc: the channel object
>   * @iov: the array of memory regions to write data from
> diff --git a/io/channel.c b/io/channel.c
> index c5a1bd5..82203ef 100644
> --- a/io/channel.c
> +++ b/io/channel.c
> @@ -87,6 +87,43 @@ ssize_t qio_channel_writev_full(QIOChannel *ioc,
>  
>  
>  
> +ssize_t qio_channel_readv_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_readv(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 read full iov");
> +            done = -1;
> +            goto cleanup;
> +        }
> +
> +        iov_discard_front(&local_iov, &nlocal_iov, len);
> +        done += len;
> +    }
> +
> + cleanup:
> +    g_free(local_iov_head);
> +    return done;
> +}
> +

Again, can you make sure this is covered in the test suite - the
test_io_thread_reader() method can probably be replaced by this code.


Regards,
Daniel
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