net: enetc: use truesize as XDP RxQ info frag_size

The only user of frag_size field in XDP RxQ info is
bpf_xdp_frags_increase_tail(). It clearly expects truesize instead of DMA
write size. Different assumptions in enetc driver configuration lead to
negative tailroom.

Set frag_size to the same value as frame_sz.

Fixes: 2768b2e ("net: enetc: register XDP RX queues with frag_size")
Reviewed-by: Aleksandr Loktionov <[email protected]>
Reviewed-by: Vladimir Oltean <[email protected]>
Signed-off-by: Larysa Zaremba <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

Author: walking-machine

drivers/net/ethernet/freescale/enetc/enetc.c

@@ -3467,7 +3467,7 @@ static int enetc_int_vector_init(struct enetc_ndev_priv *priv, int i,
 	priv->rx_ring[i] = bdr;
 
 	err = __xdp_rxq_info_reg(&bdr->xdp.rxq, priv->ndev, i, 0,
-				 ENETC_RXB_DMA_SIZE_XDP);
+				 ENETC_RXB_TRUESIZE);
 	if (err)
 		goto free_vector;