netdev - [PATCH net V2 1/2] net: ena: unmask MSI-X only after device initialization is completed

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Date:   Wed, 3 Jan 2018 06:17:29 +0000
From:   <netanel@...zon.com>
To:     <davem@...emloft.net>, <netdev@...r.kernel.org>
CC:     Netanel Belgazal <netanel@...zon.com>, <dwmw@...zon.com>,
        <zorik@...zon.com>, <matua@...zon.com>, <saeedb@...zon.com>,
        <msw@...zon.com>, <aliguori@...zon.com>, <nafea@...zon.com>,
        <evgenys@...zon.com>, <gtzalik@...zon.com>
Subject: [PATCH net V2 1/2] net: ena: unmask MSI-X only after device initialization is completed

From: Netanel Belgazal <netanel@...zon.com>

Under certain conditions MSI-X interrupt might arrive right after it
was unmasked in ena_up(). There is a chance it would be processed by
the driver before device ENA_FLAG_DEV_UP flag is set. In such a case
the interrupt is ignored.
ENA device operates in auto-masked mode, therefore ignoring
interrupt leaves it masked for good.
Moving unmask of interrupt to be the last step in ena_up().

Signed-off-by: Netanel Belgazal <netanel@...zon.com>
---
 drivers/net/ethernet/amazon/ena/ena_netdev.c | 26 +++++++++++++-------------
 1 file changed, 13 insertions(+), 13 deletions(-)

diff --git a/drivers/net/ethernet/amazon/ena/ena_netdev.c b/drivers/net/ethernet/amazon/ena/ena_netdev.c
index 97c5a89a9cf7..6fb28fd43eb3 100644
--- a/drivers/net/ethernet/amazon/ena/ena_netdev.c
+++ b/drivers/net/ethernet/amazon/ena/ena_netdev.c
@@ -1565,7 +1565,7 @@ static int ena_rss_configure(struct ena_adapter *adapter)
 
 static int ena_up_complete(struct ena_adapter *adapter)
 {
-	int rc, i;
+	int rc;
 
 	rc = ena_rss_configure(adapter);
 	if (rc)
@@ -1584,17 +1584,6 @@ static int ena_up_complete(struct ena_adapter *adapter)
 
 	ena_napi_enable_all(adapter);
 
-	/* Enable completion queues interrupt */
-	for (i = 0; i < adapter->num_queues; i++)
-		ena_unmask_interrupt(&adapter->tx_ring[i],
-				     &adapter->rx_ring[i]);
-
-	/* schedule napi in case we had pending packets
-	 * from the last time we disable napi
-	 */
-	for (i = 0; i < adapter->num_queues; i++)
-		napi_schedule(&adapter->ena_napi[i].napi);
-
 	return 0;
 }
 
@@ -1731,7 +1720,7 @@ static int ena_create_all_io_rx_queues(struct ena_adapter *adapter)
 
 static int ena_up(struct ena_adapter *adapter)
 {
-	int rc;
+	int rc, i;
 
 	netdev_dbg(adapter->netdev, "%s\n", __func__);
 
@@ -1774,6 +1763,17 @@ static int ena_up(struct ena_adapter *adapter)
 
 	set_bit(ENA_FLAG_DEV_UP, &adapter->flags);
 
+	/* Enable completion queues interrupt */
+	for (i = 0; i < adapter->num_queues; i++)
+		ena_unmask_interrupt(&adapter->tx_ring[i],
+				     &adapter->rx_ring[i]);
+
+	/* schedule napi in case we had pending packets
+	 * from the last time we disable napi
+	 */
+	for (i = 0; i < adapter->num_queues; i++)
+		napi_schedule(&adapter->ena_napi[i].napi);
+
 	return rc;
 
 err_up:
-- 
2.7.3.AMZN