net/ena: trigger reset on Tx prepare failure

[ upstream commit b57e105 ]

If the prepare function failed, then it means the descriptors are in the
invalid state.

This condition now triggers the reset, which should be further handled
by the application.

To notify the application about prepare function failure, the error log
was added. In general, it should never fail in normal conditions, as the
Tx function checks for the available space in the Tx ring before the
preparation even starts.

Fixes: 2081d5e ("net/ena: add reset routine")

Signed-off-by: Michal Krawczyk <mk@semihalf.com>
Reviewed-by: Shai Brandes <shaibran@amazon.com>
Reviewed-by: Shay Agroskin <shayagr@amazon.com>

drivers/net/ena/ena_ethdev.c

@@ -2537,7 +2537,11 @@ static int ena_xmit_mbuf(struct ena_ring *tx_ring, struct rte_mbuf *mbuf)
 	rc = ena_com_prepare_tx(tx_ring->ena_com_io_sq,	&ena_tx_ctx,
 		&nb_hw_desc);
 	if (unlikely(rc)) {
+		PMD_DRV_LOG(ERR, "Failed to prepare Tx buffers, rc: %d\n", rc);
 		++tx_ring->tx_stats.prepare_ctx_err;
+		tx_ring->adapter->reset_reason =
+		    ENA_REGS_RESET_DRIVER_INVALID_STATE;
+		tx_ring->adapter->trigger_reset = true;
 		return rc;
 	}