[dpdk-dev] [PATCH v2] kni: Fix request overwritten

[Elad Nachman]

Hi,

EAGAIN is propogated back to the kernel and to the caller.

We cannot retry from the kni kernel module since we hold the rtnl lock.

FYI,

Elad

בתאריך יום ב׳, 4 באוק׳ 2021, 16:05, מאת Ferruh Yigit ‏<
ferruh.yigit at intel.com>:

> On 9/24/2021 11:54 AM, Elad Nachman wrote:
> > Fix lack of multiple KNI requests handling support by introducing a
> > request in progress flag which will fail additional requests with
> > EAGAIN return code if the original request has not been processed
> > by user-space.
> >
> > Bugzilla ID: 809
>
> Hi Eric,
>
> Can you please test this patch, if it solves the issue you reported?
>
> >
> > Signed-off-by: Elad Nachman <eladv6 at gmail.com>
> > ---
> >  kernel/linux/kni/kni_net.c | 9 +++++++++
> >  lib/kni/rte_kni.c          | 2 ++
> >  lib/kni/rte_kni_common.h   | 1 +
> >  3 files changed, 12 insertions(+)
> >
>
> <...>
>
> > @@ -123,7 +124,15 @@ kni_net_process_request(struct net_device *dev,
> struct rte_kni_request *req)
> >
> >       mutex_lock(&kni->sync_lock);
> >
> > +     /* Check that existing request has been processed: */
> > +     cur_req = (struct rte_kni_request *)kni->sync_kva;
> > +     if (cur_req->req_in_progress) {
> > +             ret = -EAGAIN;
>
> Overall logic in the KNI looks good to me, this helps to serialize the
> requests
> even for async ones.
>
> But can you please clarify how it behaves in the kernel side with '-EAGAIN'
> return type? Will linux call the ndo again, or will it just fail.
>
> If it just fails should we handle the re-try on '-EAGAIN' within the kni
> module?
>
>