> -----Original Message-----
> From: Yigit, Ferruh
> Sent: Tuesday, July 03, 2018 12:57 AM
> To: Maxime Coquelin <maxime.coque...@redhat.com>; Liu, Yong
> <yong....@intel.com>; Bie, Tiwei <tiwei....@intel.com>
> Cc: Wang, Zhihong <zhihong.w...@intel.com>; dev@dpdk.org
> Subject: Re: [dpdk-dev] [PATCH v5 7/9] net/virtio: support in-order Rx and
> Tx
>
> On 7/2/2018 5:53 PM, Maxime Coquelin wrote:
> >
> >
> > On 07/02/2018 06:52 PM, Ferruh Yigit wrote:
> >> On 7/2/2018 5:41 PM, Ferruh Yigit wrote:
> >>> On 7/2/2018 2:56 PM, Marvin Liu wrote:
> >>>> IN_ORDER Rx function depends on merge-able feature. Descriptors
> >>>> allocation and free will be done in bulk.
> >>>>
> >>>> Virtio dequeue logic:
> >>>> dequeue_burst_rx(burst mbufs)
> >>>> for (each mbuf b) {
> >>>> if (b need merge) {
> >>>> merge remained mbufs
> >>>> add merged mbuf to return mbufs list
> >>>> } else {
> >>>> add mbuf to return mbufs list
> >>>> }
> >>>> }
> >>>> if (last mbuf c need merge) {
> >>>> dequeue_burst_rx(required mbufs)
> >>>> merge last mbuf c
> >>>> }
> >>>> refill_avail_ring_bulk()
> >>>> update_avail_ring()
> >>>> return mbufs list
> >>>>
> >>>> IN_ORDER Tx function can support offloading features. Packets which
> >>>> matched "can_push" option will be handled by simple xmit function.
> Those
> >>>> packets can't match "can_push" will be handled by original xmit
> function
> >>>> with in-order flag.
> >>>>
> >>>> Virtio enqueue logic:
> >>>> xmit_cleanup(used descs)
> >>>> for (each xmit mbuf b) {
> >>>> if (b can inorder xmit) {
> >>>> add mbuf b to inorder burst list
> >>>> continue
> >>>> } else {
> >>>> xmit inorder burst list
> >>>> xmit mbuf b by original function
> >>>> }
> >>>> }
> >>>> if (inorder burst list not empty) {
> >>>> xmit inorder burst list
> >>>> }
> >>>> update_avail_ring()
> >>>>
> >>>> Signed-off-by: Marvin Liu <yong....@intel.com>
> >>>> Reviewed-by: Maxime Coquelin <maxime.coque...@redhat.com>
> >>>
> >>> <...>
> >>>
> >>>> @@ -150,6 +188,83 @@ virtio_xmit_cleanup(struct virtqueue *vq,
> uint16_t num)
> >>>> }
> >>>> }
> >>>>
> >>>> +/* Cleanup from completed inorder transmits. */
> >>>> +static void
> >>>> +virtio_xmit_cleanup_inorder(struct virtqueue *vq, uint16_t num)
> >>>> +{
> >>>> + uint16_t i, used_idx, desc_idx, last_idx;
> >>>
> >>>
> >>> Getting following build error [1], from code it looks like false
> positive, but
> >>> to get rid of the build error would it be OK to set initial value to
> "desc_idx"?
> >>
> >> I applied this while merging, if this is wrong please let me know, we
> can fix in
> >> next-net, Thanks.
> >
> > Looks good to me. I didn't catch it with the GCC version I use.
>
> I didn't dig more but I also didn't get the error with regular build, the
> one
> with all DEBUGs enabled and mach=default combination gave the error, not
> sure why.
>
Ferruh,
I didn't catch this error either. I tried three gcc versions 7.2.0, 7.3.0 and
4.8.3.
May I know your gcc version?
Thanks,
Marvin
> >
> > Thanks,
> > Maxime
> >
> >>>
> >>>
> >>> [1]
> >>> .../dpdk/drivers/net/virtio/virtio_rxtx.c:195:24: error: ‘desc_idx’
> may be used
> >>> uninitialized in this function [-Werror=maybe-uninitialized]
> >>>
> >>>
> >>> uint16_t i, used_idx, desc_idx, last_idx;
> >>>
> >>>
> >>>
> >>> ^~~~~~~~
> >>>
> >>
