> On Thu, Apr 08, 2021 at 02:50:55PM +0200, Lorenzo Bianconi wrote:
> > Update multi-buffer bit (mb) in xdp_buff to notify XDP/eBPF layer and
> > XDP remote drivers if this is a "non-linear" XDP buffer. Access
> > xdp_shared_info only if xdp_buff mb is set.
> >
> > Signed-off-by: Lorenzo Bianconi <lorenzo@xxxxxxxxxx>
> > ---
> > drivers/net/ethernet/marvell/mvneta.c | 26 ++++++++++++++++++++------
> > 1 file changed, 20 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/net/ethernet/marvell/mvneta.c b/drivers/net/ethernet/marvell/mvneta.c
> > index a52e132fd2cf..94e29cce693a 100644
> > --- a/drivers/net/ethernet/marvell/mvneta.c
> > +++ b/drivers/net/ethernet/marvell/mvneta.c
> > @@ -2041,12 +2041,16 @@ mvneta_xdp_put_buff(struct mvneta_port *pp, struct mvneta_rx_queue *rxq,
> > {
> > int i;
> >
> > + if (likely(!xdp->mb))
> > + goto out;
> > +
>
> Is there any particular reason for this extra check?
xdp_sinfo->frags[] is initialized just if xdp->mb is set.
Regards,
Lorenzo
>
> > for (i = 0; i < xdp_sinfo->nr_frags; i++) {
> > skb_frag_t *frag = &xdp_sinfo->frags[i];
> >
> > page_pool_put_full_page(rxq->page_pool,
> > xdp_get_frag_page(frag), true);
> > }
> > +out:
> > page_pool_put_page(rxq->page_pool, virt_to_head_page(xdp->data),
> > sync_len, true);
> > }
> > @@ -2246,7 +2250,6 @@ mvneta_swbm_rx_frame(struct mvneta_port *pp,
> > {
> > unsigned char *data = page_address(page);
> > int data_len = -MVNETA_MH_SIZE, len;
> > - struct xdp_shared_info *xdp_sinfo;
> > struct net_device *dev = pp->dev;
> > enum dma_data_direction dma_dir;
> >
> > @@ -2270,9 +2273,6 @@ mvneta_swbm_rx_frame(struct mvneta_port *pp,
> > prefetch(data);
> > xdp_prepare_buff(xdp, data, pp->rx_offset_correction + MVNETA_MH_SIZE,
> > data_len, false);
> > -
> > - xdp_sinfo = xdp_get_shared_info_from_buff(xdp);
> > - xdp_sinfo->nr_frags = 0;
> > }
> >
> > static void
> > @@ -2307,12 +2307,18 @@ mvneta_swbm_add_rx_fragment(struct mvneta_port *pp,
> > xdp_set_frag_size(frag, data_len);
> > xdp_set_frag_page(frag, page);
> >
> > + if (!xdp->mb) {
> > + xdp_sinfo->data_length = *size;
> > + xdp->mb = 1;
> > + }
> > /* last fragment */
> > if (len == *size) {
> > struct xdp_shared_info *sinfo;
> >
> > sinfo = xdp_get_shared_info_from_buff(xdp);
> > sinfo->nr_frags = xdp_sinfo->nr_frags;
> > + sinfo->data_length = xdp_sinfo->data_length;
> > +
> > memcpy(sinfo->frags, xdp_sinfo->frags,
> > sinfo->nr_frags * sizeof(skb_frag_t));
> > }
> > @@ -2327,11 +2333,15 @@ mvneta_swbm_build_skb(struct mvneta_port *pp, struct mvneta_rx_queue *rxq,
> > struct xdp_buff *xdp, u32 desc_status)
> > {
> > struct xdp_shared_info *xdp_sinfo = xdp_get_shared_info_from_buff(xdp);
> > - int i, num_frags = xdp_sinfo->nr_frags;
> > skb_frag_t frag_list[MAX_SKB_FRAGS];
> > + int i, num_frags = 0;
> > struct sk_buff *skb;
> >
> > - memcpy(frag_list, xdp_sinfo->frags, sizeof(skb_frag_t) * num_frags);
> > + if (unlikely(xdp->mb)) {
> > + num_frags = xdp_sinfo->nr_frags;
> > + memcpy(frag_list, xdp_sinfo->frags,
> > + sizeof(skb_frag_t) * num_frags);
> > + }
> >
> > skb = build_skb(xdp->data_hard_start, PAGE_SIZE);
> > if (!skb)
> > @@ -2343,6 +2353,9 @@ mvneta_swbm_build_skb(struct mvneta_port *pp, struct mvneta_rx_queue *rxq,
> > skb_put(skb, xdp->data_end - xdp->data);
> > mvneta_rx_csum(pp, desc_status, skb);
> >
> > + if (likely(!xdp->mb))
> > + return skb;
> > +
> > for (i = 0; i < num_frags; i++) {
> > struct page *page = xdp_get_frag_page(&frag_list[i]);
> >
> > @@ -2404,6 +2417,7 @@ static int mvneta_rx_swbm(struct napi_struct *napi,
> > frame_sz = size - ETH_FCS_LEN;
> > desc_status = rx_status;
> >
> > + xdp_buf.mb = 0;
> > mvneta_swbm_rx_frame(pp, rx_desc, rxq, &xdp_buf,
> > &size, page);
> > } else {
> > --
> > 2.30.2
> >
>
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