bnxt_en: Flush XDP for bnxt_poll_nitroa0()'s NAPI

bnxt_poll_nitroa0() invokes bnxt_rx_pkt() which can run a XDP program
which in turn can return XDP_REDIRECT. bnxt_rx_pkt() is also used by
__bnxt_poll_work() which flushes (xdp_do_flush()) the packets after each
round. bnxt_poll_nitroa0() lacks this feature.
xdp_do_flush() should be invoked before leaving the NAPI callback.

Invoke xdp_do_flush() after a redirect in bnxt_poll_nitroa0() NAPI.

Cc: Michael Chan <michael.chan@broadcom.com>
Fixes: f18c2b7 ("bnxt_en: optimized XDP_REDIRECT support")
Reviewed-by: Andy Gospodarek <gospo@broadcom.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Michael Chan <michael.chan@broadcom.com>
Acked-by: Jesper Dangaard Brouer <hawk@kernel.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

Author: Sebastian Andrzej Siewior

drivers/net/ethernet/broadcom/bnxt/bnxt.c

@@ -2614,6 +2614,7 @@ static int bnxt_poll_nitroa0(struct napi_struct *napi, int budget)
 	struct rx_cmp_ext *rxcmp1;
 	u32 cp_cons, tmp_raw_cons;
 	u32 raw_cons = cpr->cp_raw_cons;
+	bool flush_xdp = false;
 	u32 rx_pkts = 0;
 	u8 event = 0;
 
@@ -2648,6 +2649,8 @@ static int bnxt_poll_nitroa0(struct napi_struct *napi, int budget)
 				rx_pkts++;
 			else if (rc == -EBUSY)	/* partial completion */
 				break;
+			if (event & BNXT_REDIRECT_EVENT)
+				flush_xdp = true;
 		} else if (unlikely(TX_CMP_TYPE(txcmp) ==
 				    CMPL_BASE_TYPE_HWRM_DONE)) {
 			bnxt_hwrm_handler(bp, txcmp);
@@ -2667,6 +2670,8 @@ static int bnxt_poll_nitroa0(struct napi_struct *napi, int budget)
 
 	if (event & BNXT_AGG_EVENT)
 		bnxt_db_write(bp, &rxr->rx_agg_db, rxr->rx_agg_prod);
+	if (flush_xdp)
+		xdp_do_flush();
 
 	if (!bnxt_has_work(bp, cpr) && rx_pkts < budget) {
 		napi_complete_done(napi, rx_pkts);