On Thu, May 13, 2021 at 8:21 PM Russell King (Oracle)
[off-list ref] wrote:

On Thu, May 13, 2021 at 06:58:45PM +0200, Matteo Croce wrote:

quoted

diff --git a/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c b/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c
index b2259bf1d299..9dceabece56c 100644
--- a/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c
+++ b/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c

@@ -3847,6 +3847,7 @@ static int mvpp2_rx(struct mvpp2_port *port, struct napi_struct *napi,
      struct mvpp2_pcpu_stats ps = {};
      enum dma_data_direction dma_dir;
      struct bpf_prog *xdp_prog;
+     struct xdp_rxq_info *rxqi;
      struct xdp_buff xdp;
      int rx_received;
      int rx_done = 0;

@@ -3912,15 +3913,15 @@ static int mvpp2_rx(struct mvpp2_port *port, struct napi_struct *napi,
              else
                      frag_size = bm_pool->frag_size;

+             if (bm_pool->pkt_size == MVPP2_BM_SHORT_PKT_SIZE)
+                     rxqi = &rxq->xdp_rxq_short;
+             else
+                     rxqi = &rxq->xdp_rxq_long;

+             if (xdp_prog) {
+                     xdp.rxq = rxqi;

+                     xdp_init_buff(&xdp, PAGE_SIZE, rxqi);
                      xdp_prepare_buff(&xdp, data,
                                       MVPP2_MH_SIZE + MVPP2_SKB_HEADROOM,
                                       rx_bytes, false);

@@ -3964,7 +3965,7 @@ static int mvpp2_rx(struct mvpp2_port *port, struct napi_struct *napi,
              }

              if (pp)
+                     skb_mark_for_recycle(skb, virt_to_page(data), pp);
              else
                      dma_unmap_single_attrs(dev->dev.parent, dma_addr,
                                             bm_pool->buf_size, DMA_FROM_DEVICE,

Looking at the above, which I've only quoted the _resulting_ code after
your patch above, I don't see why you have moved the
"bm_pool->pkt_size == MVPP2_BM_SHORT_PKT_SIZE" conditional outside of
the test for xdp_prog - I don't see rxqi being used except within that
conditional. Please can you explain the reasoning there?

Back in v3, skb_mark_for_recycle() was accepting an xdp_mem_info*, so
I needed rxqi out of that conditional scope to get that pointer.
Now we just need a page_pool*, so I can restore the original chunk.
Nice catch.

Thanks,
-- 
per aspera ad upstream