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From:   Harini Katakam <harini.katakam@xilinx.com>
To:     <nicolas.ferre@microchip.com>, <davem@davemloft.net>,
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        <michal.simek@xilinx.com>, <harinikatakamlinux@gmail.com>,
        <harini.katakam@xilinx.com>, <radhey.shyam.pandey@xilinx.com>
Subject: [PATCH] net: macb: Disable macb pad and fcs for fragmented packets
Date:   Mon, 9 May 2022 17:45:13 +0530
Message-ID: <20220509121513.30549-1-harini.katakam@xilinx.com>
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data_len in skbuff represents bytes resident in fragment lists or
unmapped page buffers. For such packets, when data_len is non-zero,
skb_put cannot be used - this will throw a kernel bug. Hence do not
use macb_pad_and_fcs for such fragments.

Signed-off-by: Harini Katakam <harini.katakam@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Radhey Shyam Pandey <radhey.shyam.pandey@xilinx.com>
---
 drivers/net/ethernet/cadence/macb_main.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c
index 6434e74c04f1..0b03305ad6a0 100644
--- a/drivers/net/ethernet/cadence/macb_main.c
+++ b/drivers/net/ethernet/cadence/macb_main.c
@@ -1995,7 +1995,8 @@ static unsigned int macb_tx_map(struct macb *bp,
 			ctrl |= MACB_BF(TX_LSO, lso_ctrl);
 			ctrl |= MACB_BF(TX_TCP_SEQ_SRC, seq_ctrl);
 			if ((bp->dev->features & NETIF_F_HW_CSUM) &&
-			    skb->ip_summed != CHECKSUM_PARTIAL && !lso_ctrl)
+			    skb->ip_summed != CHECKSUM_PARTIAL && !lso_ctrl &&
+			    (skb->data_len == 0))
 				ctrl |= MACB_BIT(TX_NOCRC);
 		} else
 			/* Only set MSS/MFS on payload descriptors
@@ -2091,9 +2092,11 @@ static int macb_pad_and_fcs(struct sk_buff **skb, struct net_device *ndev)
 	struct sk_buff *nskb;
 	u32 fcs;
 
+	/* Not available for GSO and fragments */
 	if (!(ndev->features & NETIF_F_HW_CSUM) ||
 	    !((*skb)->ip_summed != CHECKSUM_PARTIAL) ||
-	    skb_shinfo(*skb)->gso_size)	/* Not available for GSO */
+	    skb_shinfo(*skb)->gso_size ||
+	    ((*skb)->data_len > 0))
 		return 0;
 
 	if (padlen <= 0) {
-- 
2.17.1