netdev - [PATCH net-next 10/12] ibmvnic: Correctly re-enable interrupts in NAPI polling routine

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Message-Id: <1605208207-1896-11-git-send-email-tlfalcon@linux.ibm.com>
Date:   Thu, 12 Nov 2020 13:10:05 -0600
From:   Thomas Falcon <tlfalcon@...ux.ibm.com>
To:     netdev@...r.kernel.org
Cc:     linuxppc-dev@...ts.ozlabs.org, dnbanerg@...ibm.com,
        brking@...ux.vnet.ibm.com, pradeep@...ibm.com,
        drt@...ux.vnet.ibm.com, sukadev@...ux.vnet.ibm.com,
        ljp@...ux.vnet.ibm.com, cforno12@...ux.ibm.com,
        tlfalcon@...ux.ibm.com, ricklind@...ux.ibm.com
Subject: [PATCH net-next 10/12] ibmvnic: Correctly re-enable interrupts in NAPI polling routine

From: "Dwip N. Banerjee" <dnbanerg@...ibm.com>

If the current NAPI polling loop exits without completing it's
budget, only re-enable interrupts if there are no entries remaining
in the queue and napi_complete_done is successful. If there are entries
remaining on the queue that were missed, restart the polling loop.

Signed-off-by: Dwip N. Banerjee <dnbanerg@...ibm.com>
---
 drivers/net/ethernet/ibm/ibmvnic.c | 37 +++++++++++++++++++-----------
 1 file changed, 23 insertions(+), 14 deletions(-)

diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c
index dc42bdc6d3e1..e48a44d8884c 100644
--- a/drivers/net/ethernet/ibm/ibmvnic.c
+++ b/drivers/net/ethernet/ibm/ibmvnic.c
@@ -2387,10 +2387,17 @@ static void remove_buff_from_pool(struct ibmvnic_adapter *adapter,
 
 static int ibmvnic_poll(struct napi_struct *napi, int budget)
 {
-	struct net_device *netdev = napi->dev;
-	struct ibmvnic_adapter *adapter = netdev_priv(netdev);
-	int scrq_num = (int)(napi - adapter->napi);
-	int frames_processed = 0;
+	struct ibmvnic_sub_crq_queue *rx_scrq;
+	struct ibmvnic_adapter *adapter;
+	struct net_device *netdev;
+	int frames_processed;
+	int scrq_num;
+
+	netdev = napi->dev;
+	adapter = netdev_priv(netdev);
+	scrq_num = (int)(napi - adapter->napi);
+	frames_processed = 0;
+	rx_scrq = adapter->rx_scrq[scrq_num];
 
 restart_poll:
 	while (frames_processed < budget) {
@@ -2403,16 +2410,16 @@ static int ibmvnic_poll(struct napi_struct *napi, int budget)
 
 		if (unlikely(test_bit(0, &adapter->resetting) &&
 			     adapter->reset_reason != VNIC_RESET_NON_FATAL)) {
-			enable_scrq_irq(adapter, adapter->rx_scrq[scrq_num]);
+			enable_scrq_irq(adapter, rx_scrq);
 			napi_complete_done(napi, frames_processed);
 			return frames_processed;
 		}
 
-		if (!pending_scrq(adapter, adapter->rx_scrq[scrq_num]))
+		if (!pending_scrq(adapter, rx_scrq))
 			break;
 		/* ensure that we do not prematurely exit the polling loop */
 		dma_rmb();
-		next = ibmvnic_next_scrq(adapter, adapter->rx_scrq[scrq_num]);
+		next = ibmvnic_next_scrq(adapter, rx_scrq);
 		rx_buff =
 		    (struct ibmvnic_rx_buff *)be64_to_cpu(next->
 							  rx_comp.correlator);
@@ -2471,14 +2478,16 @@ static int ibmvnic_poll(struct napi_struct *napi, int budget)
 
 	if (adapter->state != VNIC_CLOSING)
 		replenish_rx_pool(adapter, &adapter->rx_pool[scrq_num]);
-
 	if (frames_processed < budget) {
-		enable_scrq_irq(adapter, adapter->rx_scrq[scrq_num]);
-		napi_complete_done(napi, frames_processed);
-		if (pending_scrq(adapter, adapter->rx_scrq[scrq_num]) &&
-		    napi_reschedule(napi)) {
-			disable_scrq_irq(adapter, adapter->rx_scrq[scrq_num]);
-			goto restart_poll;
+		if (napi_complete_done(napi, frames_processed)) {
+			enable_scrq_irq(adapter, rx_scrq);
+			if (pending_scrq(adapter, rx_scrq)) {
+				rmb();
+				if (napi_reschedule(napi)) {
+					disable_scrq_irq(adapter, rx_scrq);
+					goto restart_poll;
+				}
+			}
 		}
 	}
 	return frames_processed;
-- 
2.26.2