net/mlx5e: SHAMPO, Fix invalid WQ linked list unlink

When all the strides in a WQE have been consumed, the WQE is unlinked
from the WQ linked list (mlx5_wq_ll_pop()). For SHAMPO, it is possible
to receive CQEs with 0 consumed strides for the same WQE even after the
WQE is fully consumed and unlinked. This triggers an additional unlink
for the same wqe which corrupts the linked list.

Fix this scenario by accepting 0 sized consumed strides without
unlinking the WQE again.

Signed-off-by: Dragos Tatulea <[email protected]>
Signed-off-by: Tariq Toukan <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

Author: dtatulea

drivers/net/ethernet/mellanox/mlx5/core/en_rx.c

@@ -2375,6 +2375,9 @@ static void mlx5e_handle_rx_cqe_mpwrq_shampo(struct mlx5e_rq *rq, struct mlx5_cq
 	if (likely(wi->consumed_strides < rq->mpwqe.num_strides))
 		return;
 
+	if (unlikely(!cstrides))
+		return;
+
 	wq  = &rq->mpwqe.wq;
 	wqe = mlx5_wq_ll_get_wqe(wq, wqe_id);
 	mlx5_wq_ll_pop(wq, cqe->wqe_id, &wqe->next.next_wqe_index);