[dpdk-stable] [PATCH 16.11] vhost-user: fix false negative in handling user messages

[Luca Boccassi]

On Thu, 2018-11-29 at 10:58 +0300, Ilya Maximets wrote:
> On 28.11.2018 19:20, Luca Boccassi wrote:
> > vhost_user_msg_handler checks an accumulated return code before
> > returning, and prints an error and returns -1 if it's non-zero.
> > But some of the possible user messages cannot fail and thus do not
> > set the variable, which might retain a previously set and unrelated
> > value, causing unnecessary failures and error messages.
> > 
> > Reset the return code before use.
> > 
> > Fixes: 0ce9e73d1e8d ("vhost-user: drop connection on message
> > handling failures")
> > 
> > Signed-off-by: Luca Boccassi <bluca at debian.org>
> > ---
> > Found this issue when testing with the Vyatta stuff, "ret" is set
> > at
> > the beginning of the function and never reset when the message is
> > for example
> > VHOST_USER_GET_FEATURES so there's a flurry of errors.
> 
> Hmm. Yes, current implementation in 16.11 branch doesn't work at all.
> I think that it's a kind of an issue in the original patch 0d7853a4d.
> But it uncovered only after backporting. On master we had additional
> call 'ret = vhost_user_check_and_alloc_queue_pair()' before the main
> handling switch and this function could only return 0 or -1. So, the
> 'ret' was always zero if we reached the handling switch.
> 
> LGTM,
> Acked-by: Ilya Maximets <i.maximets at samsung.com>

I see. Thank you both for the reviews, applied and pushed.

-- 
Kind regards,
Luca Boccassi