Re: [PATCH v15 07/20] multi-process: add qio channel write function

[Daniel P . Berrangé]

Since this is independent of the multi-process code, it
should have a subject prefix of "io:". I'd suggest

   io: add qio_channel_writev_full_all helper

On Tue, Dec 22, 2020 at 10:14:42PM -0800, elena.ufimtseva@oracle.com wrote:
> From: Elena Ufimtseva <elena.ufimtseva@oracle.com>
> 
> Adds qio_channel_writev_full_all() to transmit both data and FDs.
> Refactors existing code to use this function.
> 
> Signed-off-by: Elena Ufimtseva <elena.ufimtseva@oracle.com>
> Signed-off-by: John G Johnson <john.g.johnson@oracle.com>
> Signed-off-by: Jagannathan Raman <jag.raman@oracle.com>
> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
> ---
>  include/io/channel.h | 25 +++++++++++++++++++++++++
>  io/channel.c         | 17 ++++++++++++++++-
>  2 files changed, 41 insertions(+), 1 deletion(-)
> 
> diff --git a/include/io/channel.h b/include/io/channel.h
> index 4d6fe45f63..2378567d4b 100644
> --- a/include/io/channel.h
> +++ b/include/io/channel.h
> @@ -774,4 +774,29 @@ void qio_channel_set_aio_fd_handler(QIOChannel *ioc,
>                                      IOHandler *io_write,
>                                      void *opaque);
>  
> +/**
> + * qio_channel_writev_full_all:
> + * @ioc: the channel object
> + * @iov: the array of memory regions to write data from
> + * @niov: the length of the @iov array
> + * @fds: an array of file handles to send
> + * @nfds: number of file handles in @fds
> + * @errp: pointer to a NULL-initialized error object
> + *
> + *
> + * Behaves like qio_channel_writev_full but will attempt
> + * to send all data passed (file handles and memory regions).
> + * The function will wait for all requested data
> + * to be written, yielding from the current coroutine
> + * if required.
> + *
> + * Returns: 0 if all bytes were written, or -1 on error
> + */
> +
> +int qio_channel_writev_full_all(QIOChannel *ioc,
> +                           const struct iovec *iov,
> +                           size_t niov,
> +                           int *fds, size_t nfds,
> +                           Error **errp);

Copy-paste mistake - alignment of parameters is incorrect now.

> +
>  #endif /* QIO_CHANNEL_H */
> diff --git a/io/channel.c b/io/channel.c
> index 93d449dee2..bde1f6d0f4 100644
> --- a/io/channel.c
> +++ b/io/channel.c
> @@ -156,11 +156,22 @@ int qio_channel_writev_all(QIOChannel *ioc,
>                             const struct iovec *iov,
>                             size_t niov,
>                             Error **errp)
> +{
> +    return qio_channel_writev_full_all(ioc, iov, niov, NULL, 0, errp);
> +}
> +
> +int qio_channel_writev_full_all(QIOChannel *ioc,
> +                                const struct iovec *iov,
> +                                size_t niov,
> +                                int *fds, size_t nfds,
> +                                Error **errp)
>  {
>      int ret = -1;
>      struct iovec *local_iov = g_new(struct iovec, niov);
>      struct iovec *local_iov_head = local_iov;
>      unsigned int nlocal_iov = niov;
> +    int *local_fds = fds;
> +    size_t local_nfds = nfds;

I don't see any need for these extra variables - just
use the parameters in place

>  
>      nlocal_iov = iov_copy(local_iov, nlocal_iov,
>                            iov, niov,
> @@ -168,7 +179,8 @@ int qio_channel_writev_all(QIOChannel *ioc,
>  
>      while (nlocal_iov > 0) {
>          ssize_t len;
> -        len = qio_channel_writev(ioc, local_iov, nlocal_iov, errp);
> +        len = qio_channel_writev_full(ioc, local_iov, nlocal_iov, local_fds,
> +                                      local_nfds, errp);
>          if (len == QIO_CHANNEL_ERR_BLOCK) {
>              if (qemu_in_coroutine()) {
>                  qio_channel_yield(ioc, G_IO_OUT);
> @@ -182,6 +194,9 @@ int qio_channel_writev_all(QIOChannel *ioc,
>          }
>  
>          iov_discard_front(&local_iov, &nlocal_iov, len);
> +
> +        local_fds = NULL;
> +        local_nfds = 0;
>      }
>  
>      ret = 0;

If the above tweaks are made then

   Acked-by: Daniel P. Berrangé <berrange@redhat.com>

Regards,
Daniel
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