Re: [Qemu-devel] [PATCH 03/20] char: add IOWatchPoll support

[Amit Shah <amit.shah@redhat.com>]

On (Tue) 05 Mar 2013 [23:21:18], Amit Shah wrote:
> From: Anthony Liguori <aliguori@us.ibm.com>
> 
> This is a special GSource that supports CharDriverState style
> poll callbacks.
> 
> For reviewability and bisectability, this code is #if 0'd out in this
> patch to avoid unused warnings since all of the functions are static.
> 
> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
> Signed-off-by: Amit Shah <amit.shah@redhat.com>


> +static int io_channel_send_all(GIOChannel *fd, const void *_buf, int len1)
> +{
> +    GIOStatus status;
> +    gsize bytes_written;
> +    int len;
> +    const uint8_t *buf = _buf;
> +
> +    len = len1;
> +    while (len > 0) {
> +        status = g_io_channel_write_chars(fd, (const gchar *)buf, len,
> +                                          &bytes_written, NULL);
> +        if (status != G_IO_STATUS_NORMAL) {
> +            if (status != G_IO_STATUS_AGAIN) {
> +                return -1;
> +            }

It's not quite right to return -1 here; previous iterations of the
while loop could have successfully written data, and (len1 - len)
could be +ve.

How to approach this?  Convert all callers of qemu_chr_fe_write() to
also pass a bytes_written param to handle this case?

> +        } else if (status == G_IO_STATUS_EOF) {
> +            break;
> +        } else {
> +            buf += bytes_written;
> +            len -= bytes_written;
> +        }
> +    }
> +    return len1 - len;
> +}
> +#endif
> +
>  typedef struct {
>      int fd_in, fd_out;
>      int max_size;

		Amit