Re: [PATCH 11/20] migration: hardcode assumption that QEMUFile is backed with QIOChannel

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

* Daniel P. Berrangé (berrange@redhat.com) wrote:
> The only callers of qemu_fopen_ops pass 'true' for the 'has_ioc'
> parameter, so hardcode this assumption in QEMUFile, by passing in
> the QIOChannel object as a non-opaque parameter.
> 
> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>

Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

> ---
>  migration/qemu-file-channel.c |  4 ++--
>  migration/qemu-file.c         | 35 +++++++++++++++++------------------
>  migration/qemu-file.h         |  2 +-
>  3 files changed, 20 insertions(+), 21 deletions(-)
> 
> diff --git a/migration/qemu-file-channel.c b/migration/qemu-file-channel.c
> index bb5a5752df..ce8eced417 100644
> --- a/migration/qemu-file-channel.c
> +++ b/migration/qemu-file-channel.c
> @@ -184,11 +184,11 @@ static const QEMUFileOps channel_output_ops = {
>  QEMUFile *qemu_fopen_channel_input(QIOChannel *ioc)
>  {
>      object_ref(OBJECT(ioc));
> -    return qemu_fopen_ops(ioc, &channel_input_ops, true);
> +    return qemu_fopen_ops(ioc, &channel_input_ops);
>  }
>  
>  QEMUFile *qemu_fopen_channel_output(QIOChannel *ioc)
>  {
>      object_ref(OBJECT(ioc));
> -    return qemu_fopen_ops(ioc, &channel_output_ops, true);
> +    return qemu_fopen_ops(ioc, &channel_output_ops);
>  }
> diff --git a/migration/qemu-file.c b/migration/qemu-file.c
> index 6badc8b0ec..ea1e8da0cb 100644
> --- a/migration/qemu-file.c
> +++ b/migration/qemu-file.c
> @@ -37,7 +37,7 @@
>  struct QEMUFile {
>      const QEMUFileOps *ops;
>      const QEMUFileHooks *hooks;
> -    void *opaque;
> +    QIOChannel *ioc;
>  
>      /*
>       * Maximum amount of data in bytes to transfer during one
> @@ -65,8 +65,6 @@ struct QEMUFile {
>      Error *last_error_obj;
>      /* has the file has been shutdown */
>      bool shutdown;
> -    /* Whether opaque points to a QIOChannel */
> -    bool has_ioc;
>  };
>  
>  /*
> @@ -81,7 +79,7 @@ int qemu_file_shutdown(QEMUFile *f)
>      if (!f->ops->shut_down) {
>          return -ENOSYS;
>      }
> -    ret = f->ops->shut_down(f->opaque, true, true, NULL);
> +    ret = f->ops->shut_down(f->ioc, true, true, NULL);
>  
>      if (!f->last_error) {
>          qemu_file_set_error(f, -EIO);
> @@ -98,7 +96,7 @@ QEMUFile *qemu_file_get_return_path(QEMUFile *f)
>      if (!f->ops->get_return_path) {
>          return NULL;
>      }
> -    return f->ops->get_return_path(f->opaque);
> +    return f->ops->get_return_path(f->ioc);
>  }
>  
>  bool qemu_file_mode_is_not_valid(const char *mode)
> @@ -113,15 +111,15 @@ bool qemu_file_mode_is_not_valid(const char *mode)
>      return false;
>  }
>  
> -QEMUFile *qemu_fopen_ops(void *opaque, const QEMUFileOps *ops, bool has_ioc)
> +QEMUFile *qemu_fopen_ops(QIOChannel *ioc, const QEMUFileOps *ops)
>  {
>      QEMUFile *f;
>  
>      f = g_new0(QEMUFile, 1);
>  
> -    f->opaque = opaque;
> +    f->ioc = ioc;
>      f->ops = ops;
> -    f->has_ioc = has_ioc;
> +
>      return f;
>  }
>  
> @@ -242,7 +240,7 @@ void qemu_fflush(QEMUFile *f)
>      }
>      if (f->iovcnt > 0) {
>          expect = iov_size(f->iov, f->iovcnt);
> -        ret = f->ops->writev_buffer(f->opaque, f->iov, f->iovcnt, f->total_transferred,
> +        ret = f->ops->writev_buffer(f->ioc, f->iov, f->iovcnt, f->total_transferred,
>                                      &local_error);
>  
>          qemu_iovec_release_ram(f);
> @@ -358,7 +356,7 @@ static ssize_t qemu_fill_buffer(QEMUFile *f)
>          return 0;
>      }
>  
> -    len = f->ops->get_buffer(f->opaque, f->buf + pending, f->total_transferred,
> +    len = f->ops->get_buffer(f->ioc, f->buf + pending, f->total_transferred,
>                               IO_BUF_SIZE - pending, &local_error);
>      if (len > 0) {
>          f->buf_size += len;
> @@ -394,7 +392,7 @@ int qemu_fclose(QEMUFile *f)
>      ret = qemu_file_get_error(f);
>  
>      if (f->ops->close) {
> -        int ret2 = f->ops->close(f->opaque, NULL);
> +        int ret2 = f->ops->close(f->ioc, NULL);
>          if (ret >= 0) {
>              ret = ret2;
>          }
> @@ -861,18 +859,19 @@ void qemu_put_counted_string(QEMUFile *f, const char *str)
>  void qemu_file_set_blocking(QEMUFile *f, bool block)
>  {
>      if (f->ops->set_blocking) {
> -        f->ops->set_blocking(f->opaque, block, NULL);
> +        f->ops->set_blocking(f->ioc, block, NULL);
>      }
>  }
>  
>  /*
> - * Return the ioc object if it's a migration channel.  Note: it can return NULL
> - * for callers passing in a non-migration qemufile.  E.g. see qemu_fopen_bdrv()
> - * and its usage in e.g. load_snapshot().  So we need to check against NULL
> - * before using it.  If without the check, migration_incoming_state_destroy()
> - * could fail for load_snapshot().
> + * qemu_file_get_ioc:
> + *
> + * Get the ioc object for the file, without incrementing
> + * the reference count.
> + *
> + * Returns: the ioc object
>   */
>  QIOChannel *qemu_file_get_ioc(QEMUFile *file)
>  {
> -    return file->has_ioc ? QIO_CHANNEL(file->opaque) : NULL;
> +    return file->ioc;
>  }
> diff --git a/migration/qemu-file.h b/migration/qemu-file.h
> index 6310071f90..0458b1d3b6 100644
> --- a/migration/qemu-file.h
> +++ b/migration/qemu-file.h
> @@ -118,7 +118,7 @@ typedef struct QEMUFileHooks {
>      QEMURamSaveFunc *save_page;
>  } QEMUFileHooks;
>  
> -QEMUFile *qemu_fopen_ops(void *opaque, const QEMUFileOps *ops, bool has_ioc);
> +QEMUFile *qemu_fopen_ops(QIOChannel *ioc, const QEMUFileOps *ops);
>  void qemu_file_set_hooks(QEMUFile *f, const QEMUFileHooks *hooks);
>  int qemu_get_fd(QEMUFile *f);
>  int qemu_fclose(QEMUFile *f);
> -- 
> 2.36.1
> 
-- 
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK