FAILED: patch "[PATCH] net: ena: Fix wrong rx request id by resetting device" failed to apply to 4.9-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 4.9-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From cb3d4f98f0b26eafa0b913ac3716e4714254a747 Mon Sep 17 00:00:00 2001
From: Arthur Kiyanovski <akiyano@amazon.com>
Date: Sun, 2 Jan 2022 07:37:27 +0000
Subject: [PATCH] net: ena: Fix wrong rx request id by resetting device

A wrong request id received from the device is a sign that
something is wrong with it, therefore trigger a device reset.

Also add some debug info to the "Page is NULL" print to make
it easier to debug.

Fixes: 1738cd3ed342 ("net: ena: Add a driver for Amazon Elastic Network Adapters (ENA)")
Signed-off-by: Arthur Kiyanovski <akiyano@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/amazon/ena/ena_netdev.c b/drivers/net/ethernet/amazon/ena/ena_netdev.c
index 2274063e34cc..52a8c60b7e29 100644
--- a/drivers/net/ethernet/amazon/ena/ena_netdev.c
+++ b/drivers/net/ethernet/amazon/ena/ena_netdev.c
@@ -1428,6 +1428,7 @@ static struct sk_buff *ena_rx_skb(struct ena_ring *rx_ring,
 				  u16 *next_to_clean)
 {
 	struct ena_rx_buffer *rx_info;
+	struct ena_adapter *adapter;
 	u16 len, req_id, buf = 0;
 	struct sk_buff *skb;
 	void *page_addr;
@@ -1440,8 +1441,14 @@ static struct sk_buff *ena_rx_skb(struct ena_ring *rx_ring,
 	rx_info = &rx_ring->rx_buffer_info[req_id];
 
 	if (unlikely(!rx_info->page)) {
-		netif_err(rx_ring->adapter, rx_err, rx_ring->netdev,
-			  "Page is NULL\n");
+		adapter = rx_ring->adapter;
+		netif_err(adapter, rx_err, rx_ring->netdev,
+			  "Page is NULL. qid %u req_id %u\n", rx_ring->qid, req_id);
+		ena_increase_stat(&rx_ring->rx_stats.bad_req_id, 1, &rx_ring->syncp);
+		adapter->reset_reason = ENA_REGS_RESET_INV_RX_REQ_ID;
+		/* Make sure reset reason is set before triggering the reset */
+		smp_mb__before_atomic();
+		set_bit(ENA_FLAG_TRIGGER_RESET, &adapter->flags);
 		return NULL;
 	}