Amit Shah <[email protected]> writes:
> On (Fri) 29 Mar 2013 [07:24:07], Anthony Liguori wrote:
>> Amit Shah <[email protected]> writes:
>>
>> > On (Tue) 05 Mar 2013 [23:21:18], Amit Shah wrote:
>> >> From: Anthony Liguori <[email protected]>
>> >>
>> >> 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 <[email protected]>
>> >> Signed-off-by: Amit Shah <[email protected]>
>> >
>> >
>> >> +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.
>>
>> Once -1 is returned, it's a terminal error. It doesn't matter that we
>> may have written some data.
>
> Why do you say that?
Because you're quoting the wrong patch :-) This bit is rewritten by a
later patch which is the source of your problem below. In the patch you
quote, we busy spin until all data is written. However, with:
commit 23673ca740e0eda66901ca801a5a901df378b063
Author: Anthony Liguori <[email protected]>
Date: Tue Mar 5 23:21:23 2013 +0530
qemu-char: add watch support
We started to return EAGAIN even if we have a partially successful
write. I'm running a patch through testing right now that rewrites this
function to have sane semantics (return bytes written on partial write).
I'll post as soon as testing completes.
Regards,
Anthony Liguori
