netdev - [PATCH net] ionic: fix txrx work accounting

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Message-Id: <20200827234422.47351-1-snelson@pensando.io>
Date:   Thu, 27 Aug 2020 16:44:22 -0700
From:   Shannon Nelson <snelson@...sando.io>
To:     netdev@...r.kernel.org, davem@...emloft.net
Cc:     Shannon Nelson <snelson@...sando.io>
Subject: [PATCH net] ionic: fix txrx work accounting

Take the tx accounting out of the work_done calculation to
prevent a possible duplicate napi_schedule call when under
high Tx stress but low Rx traffic.

Fixes: b14e4e95f9ec ("ionic: tx separate servicing")
Signed-off-by: Shannon Nelson <snelson@...sando.io>
---
 drivers/net/ethernet/pensando/ionic/ionic_txrx.c | 13 +++----------
 1 file changed, 3 insertions(+), 10 deletions(-)

diff --git a/drivers/net/ethernet/pensando/ionic/ionic_txrx.c b/drivers/net/ethernet/pensando/ionic/ionic_txrx.c
index 8107d32c2767..def65fee27b5 100644
--- a/drivers/net/ethernet/pensando/ionic/ionic_txrx.c
+++ b/drivers/net/ethernet/pensando/ionic/ionic_txrx.c
@@ -496,9 +496,7 @@ int ionic_txrx_napi(struct napi_struct *napi, int budget)
 	struct ionic_cq *txcq;
 	u32 rx_work_done = 0;
 	u32 tx_work_done = 0;
-	u32 work_done = 0;
 	u32 flags = 0;
-	bool unmask;
 
 	lif = rxcq->bound_q->lif;
 	idev = &lif->ionic->idev;
@@ -512,17 +510,12 @@ int ionic_txrx_napi(struct napi_struct *napi, int budget)
 	if (rx_work_done)
 		ionic_rx_fill_cb(rxcq->bound_q);
 
-	unmask = (rx_work_done < budget) && (tx_work_done < lif->tx_budget);
-
-	if (unmask && napi_complete_done(napi, rx_work_done)) {
+	if (rx_work_done < budget && napi_complete_done(napi, rx_work_done)) {
 		flags |= IONIC_INTR_CRED_UNMASK;
 		DEBUG_STATS_INTR_REARM(rxcq->bound_intr);
-		work_done = rx_work_done;
-	} else {
-		work_done = budget;
 	}
 
-	if (work_done || flags) {
+	if (rx_work_done || flags) {
 		flags |= IONIC_INTR_CRED_RESET_COALESCE;
 		ionic_intr_credits(idev->intr_ctrl, rxcq->bound_intr->index,
 				   tx_work_done + rx_work_done, flags);
@@ -531,7 +524,7 @@ int ionic_txrx_napi(struct napi_struct *napi, int budget)
 	DEBUG_STATS_NAPI_POLL(qcq, rx_work_done);
 	DEBUG_STATS_NAPI_POLL(qcq, tx_work_done);
 
-	return work_done;
+	return rx_work_done;
 }
 
 static dma_addr_t ionic_tx_map_single(struct ionic_queue *q,
-- 
2.17.1