On 2025-12-18 at 12:06:47, Wei Fang (wei.fang@nxp.com) wrote:

quoted

On 2025-12-17 at 18:19:19, Wei Fang (wei.fang@nxp.com) wrote:

quoted

quoted

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-	res = stmmac_xdp_xmit_xdpf(priv, queue, xdpf, false);
-	if (res == STMMAC_XDP_TX)
+	/* For zero copy XDP_TX action, dma_map is true */
+	res = stmmac_xdp_xmit_xdpf(priv, queue, xdpf, zc);

	Seems stmmac_xdp_xmit_xdpf is using dma_map_single if we pass zc is
true.
        Ideally in case of zc, driver can use
page_pool_get_dma_addr, may be you
        need pass zc param as false. Please check

No, the memory type of xdpf->data is MEM_TYPE_PAGE_ORDER0 rather than
MEM_TYPE_PAGE_POOL, so we should use dma_map_single().
Otherwise, it will lead to invalid mappings and cause the crash.

 ACK, found below code bit confusing
		case STMMAC_XDP_CONSUMED:
 			xsk_buff_free(buf->xdp);
+			fallthrough;
+		case STMMAC_XSK_CONSUMED:
 			rx_dropped++;

     Ideally in case of STMMAC_XSK_CONSUMED, driver needs to call
xsk_buff_free.
     And in case of STMMAC_XDP_CONSUMED, driver needs to call
xdp_return_frame.
     May be you can move all buffer free logic to stmmac_rx_zc with above
suggested
     changes.

For zero copy, the xdp_buff is freed by xdp_convert_buff_to_frame()
when converting the xdp_xdp to xdp_frame. So STMMAC_XSK_CONSUMED
means the xdp_buff has been freed, it tells stmmac_rx_zc() no to free a
xdp_buff that has been freed.

I have added a comment for STMMAC_XSK_CONSUMED, see

+       } else if (res == STMMAC_XDP_CONSUMED && zc) {
+               /* xdp has been freed by xdp_convert_buff_to_frame(),
+                * no need to call xsk_buff_free() again, so return
+                * STMMAC_XSK_CONSUMED.
+                */
+               res = STMMAC_XSK_CONSUMED;
+               xdp_return_frame(xdpf);
+       }

 ACK. 
Reviewed-by: Hariprasad Kelam <hkelam@marvell.com>