FAILED: patch "[PATCH] qede: validate non LSO skb length" failed to apply to 4.9-stable tree

[<gregkh@xxxxxxxxxxxxxxxxxxx>]

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@xxxxxxxxxxxxxxx>.

thanks,

greg k-h

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

>From 8e227b198a55859bf790dc7f4b1e30c0859c6756 Mon Sep 17 00:00:00 2001
From: Manish Chopra <manishc@xxxxxxxxxxx>
Date: Fri, 3 Dec 2021 09:44:13 -0800
Subject: [PATCH] qede: validate non LSO skb length

Although it is unlikely that stack could transmit a non LSO
skb with length > MTU, however in some cases or environment such
occurrences actually resulted into firmware asserts due to packet
length being greater than the max supported by the device (~9700B).

This patch adds the safeguard for such odd cases to avoid firmware
asserts.

v2: Added "Fixes" tag with one of the initial driver commit
    which enabled the TX traffic actually (as this was probably
    day1 issue which was discovered recently by some customer
    environment)

Fixes: a2ec6172d29c ("qede: Add support for link")
Signed-off-by: Manish Chopra <manishc@xxxxxxxxxxx>
Signed-off-by: Alok Prasad <palok@xxxxxxxxxxx>
Signed-off-by: Prabhakar Kushwaha <pkushwaha@xxxxxxxxxxx>
Signed-off-by: Ariel Elior <aelior@xxxxxxxxxxx>
Link: https://lore.kernel.org/r/20211203174413.13090-1-manishc@xxxxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>

diff --git a/drivers/net/ethernet/qlogic/qede/qede_fp.c b/drivers/net/ethernet/qlogic/qede/qede_fp.c
index 065e9004598e..999abcfe3310 100644
--- a/drivers/net/ethernet/qlogic/qede/qede_fp.c
+++ b/drivers/net/ethernet/qlogic/qede/qede_fp.c
@@ -1643,6 +1643,13 @@ netdev_tx_t qede_start_xmit(struct sk_buff *skb, struct net_device *ndev)
 			data_split = true;
 		}
 	} else {
+		if (unlikely(skb->len > ETH_TX_MAX_NON_LSO_PKT_LEN)) {
+			DP_ERR(edev, "Unexpected non LSO skb length = 0x%x\n", skb->len);
+			qede_free_failed_tx_pkt(txq, first_bd, 0, false);
+			qede_update_tx_producer(txq);
+			return NETDEV_TX_OK;
+		}
+
 		val |= ((skb->len & ETH_TX_DATA_1ST_BD_PKT_LEN_MASK) <<
 			 ETH_TX_DATA_1ST_BD_PKT_LEN_SHIFT);
 	}