Re: [PATCH v13 07/19] multi-process: add qio channel function to transmit data and fds

[Elena Ufimtseva]

On Tue, Dec 15, 2020 at 02:49:22PM +0400, Marc-André Lureau wrote:
> Hi
> 
> On Mon, Dec 14, 2020 at 9:15 AM Jagannathan Raman <jag.raman@oracle.com>
> wrote:
> 
> > From: Elena Ufimtseva <elena.ufimtseva@oracle.com>
> >
> > Adds QIO channel functions that transmit and receive iovs along with fds.
> >
> > 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 | 50 +++++++++++++++++++++++++++++++++++++++++
> >  io/channel.c         | 63
> > +++++++++++++++++++++++++++++++++++++++++++++++++++-
> >  2 files changed, 112 insertions(+), 1 deletion(-)
> >
> > diff --git a/include/io/channel.h b/include/io/channel.h
> > index 4d6fe45..c2d9836 100644
> > --- a/include/io/channel.h
> > +++ b/include/io/channel.h
> > @@ -774,4 +774,54 @@ void qio_channel_set_aio_fd_handler(QIOChannel *ioc,
> >                                      IOHandler *io_write,
> >                                      void *opaque);
> >
> > +/**
> > + * qio_channel_readv_full_all:
> > + * @ioc: the channel object
> > + * @iov: the array of memory regions to read data to
> > + * @niov: the length of the @iov array
> > + * @fds: an array of file handles to read
> > + * @nfds: number of file handles in @fds
> > + * @errp: pointer to a NULL-initialized error object
> > + *
> > + *
> > + * Behaves like qio_channel_readvv_full but will attempt
> > + * to read all data specified (file handles and memory regions).
> > + * The function will wait for all requested data
> > + * to be read, yielding from the current coroutine
> > + * if required.
> > + *
> > + * Returns: 0 if all bytes were read, or -1 on error
> > + */
> > +
> > +int qio_channel_readv_full_all(QIOChannel *ioc,
> > +                                const struct iovec *iov,
> > +                                size_t niov,
> > +                                int **fds, size_t *nfds,
> > +                                Error **errp);
> > +
> > +/**
> > + * 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);
> > +
> >  #endif /* QIO_CHANNEL_H */
> > diff --git a/io/channel.c b/io/channel.c
> > index 93d449d..13b0e7a 100644
> > --- a/io/channel.c
> > +++ b/io/channel.c
> > @@ -152,15 +152,72 @@ int qio_channel_readv_all(QIOChannel *ioc,
> >      return ret;
> >  }
> >
> > +int qio_channel_readv_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;
> > +
> > +    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_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);
> > +            } else {
> > +                qio_channel_wait(ioc, G_IO_OUT);
> > +            }
> > +            continue;
> > +        }
> > +        if (len <= 0) {
> > +            ret = len;
> > +            goto cleanup;
> > +        }
> > +
> > +        iov_discard_front(&local_iov, &nlocal_iov, len);
> > +
> > +        local_fds = NULL;
> > +        local_nfds = 0;
> > +    }
> > +
> > +    ret = 1;
> > + cleanup:
> > +    g_free(local_iov_head);
> > +    return ret;
> > +}
> > +
> >
> 
> I suggest to adapt the code so qio_channel_readv_all_eof() calls
> qio_channel_readv_full_all().
> 
> You may want to split this patch in 2 parts: the read and write parts.
>

And should we drop the Reviewed-by: Stefan Hajnoczi then?

Thanks!

Elena
> 
> >  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;
> >
> >      nlocal_iov = iov_copy(local_iov, nlocal_iov,
> >                            iov, niov,
> > @@ -168,7 +225,8 @@ 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 +240,9 @@ int qio_channel_writev_all(QIOChannel *ioc,
> >          }
> >
> >          iov_discard_front(&local_iov, &nlocal_iov, len);
> > +
> > +        local_fds = NULL;
> > +        local_nfds = 0;
> >      }
> >
> >      ret = 0;
> > --
> > 1.8.3.1
> >
> >
> 
> -- 
> Marc-André Lureau