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

[Ferruh Yigit]

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?