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Re: [Qemu-devel] [PATCH] char: fix handling of QIO_CHANNEL_ERR_BLOCK
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] [PATCH] char: fix handling of QIO_CHANNEL_ERR_BLOCK |
Date: |
Fri, 12 Feb 2016 16:24:35 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.5.0 |
On 12/02/2016 15:46, Daniel P. Berrange wrote:
> If io_channel_send_full gets QIO_CHANNEL_ERR_BLOCK it
> and has already sent some of the data, it should return
> that amount of data, not EAGAIN, as that would cause
> the caller to re-try already sent data.
>
> Unfortunately due to a previous rebase conflict resolution
> error, the code for dealing with this was in the wrong
> part of the conditional, and so mistakenly ran on other
> I/O errors.
>
> This be seen running
>
> qemu-system-x86_64 -monitor stdio
>
> and entering 'info mtree', when running on a slow console
> (eg a slow remote ssh session). The monitor would get into
> an indefinite loop writing the same data until it managed
> to send it all without getting EAGAIN.
>
> Reported-by: Igor Mammedov <address@hidden>
> Signed-off-by: Daniel P. Berrange <address@hidden>
> ---
> qemu-char.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/qemu-char.c b/qemu-char.c
> index 1b7d5da..c2e24a5 100644
> --- a/qemu-char.c
> +++ b/qemu-char.c
> @@ -896,13 +896,13 @@ static int io_channel_send_full(QIOChannel *ioc,
> ioc, &iov, 1,
> fds, nfds, NULL);
> if (ret == QIO_CHANNEL_ERR_BLOCK) {
> - errno = EAGAIN;
> - return -1;
> - } else if (ret < 0) {
> if (offset) {
> return offset;
> }
>
> + errno = EAGAIN;
> + return -1;
> + } else if (ret < 0) {
> errno = EINVAL;
> return -1;
> }
>
Queued, thanks.
Paolo