From ec20f36bb41aec786407b525ac1c2ba982c925fd Mon Sep 17 00:00:00 2001
From: "Dwip N. Banerjee" <dnbanerg@us.ibm.com>
Date: Wed, 18 Nov 2020 19:12:23 -0600
Subject: [PATCH] ibmvnic: Correctly re-enable interrupts in NAPI polling
 routine

References: bsc#1184114 ltc#192237 bsc#1179243 ltc#189290
Patch-mainline: v5.11-rc1
Git-commit: ec20f36bb41aec786407b525ac1c2ba982c925fd

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@us.ibm.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Michal Suchanek <msuchanek@suse.de>
---
 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
--- a/drivers/net/ethernet/ibm/ibmvnic.c
+++ b/drivers/net/ethernet/ibm/ibmvnic.c
@@ -2463,10 +2463,17 @@ static void remove_buff_from_pool(struct
 
 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) {
@@ -2479,12 +2486,12 @@ restart_poll:
 
 		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;
 		/* The queue entry at the current index is peeked at above
 		 * to determine that there is a valid descriptor awaiting
@@ -2492,7 +2499,7 @@ restart_poll:
 		 * holds a valid descriptor before reading its contents.
 		 */
 		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);
@@ -2551,14 +2558,16 @@ restart_poll:
 
 	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