smsx95xx: fix crimes against truesize

raspberrypi inclusion
category: feature
bugzilla: 50432

--------------------------------

smsc95xx is adjusting truesize when it shouldn't, and following a recent patch from Eric this is now triggering warnings.

This patch stops smsc95xx from changing truesize.
Signed-off-by: NSteve Glendinning <steve.glendinning@smsc.com>
Signed-off-by: NFang Yafen <yafen@iscas.ac.cn>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

drivers/net/usb/smsc95xx.c

@@ -67,6 +67,10 @@ static bool turbo_mode = true;
 module_param(turbo_mode, bool, 0644);
 MODULE_PARM_DESC(turbo_mode, "Enable multiple frames per Rx transaction");
 
+static bool truesize_mode = false;
+module_param(truesize_mode, bool, 0644);
+MODULE_PARM_DESC(truesize_mode, "Report larger truesize value");
+
 static int __must_check __smsc95xx_read_reg(struct usbnet *dev, u32 index,
 					    u32 *data, int in_pm)
 {
@@ -1827,6 +1831,7 @@ static int smsc95xx_rx_fixup(struct usbnet *dev, struct sk_buff *skb)
 				if (dev->net->features & NETIF_F_RXCSUM)
 					smsc95xx_rx_csum_offload(skb);
 				skb_trim(skb, skb->len - 4); /* remove fcs */
+				if (truesize_mode)
 					skb->truesize = size + sizeof(struct sk_buff);
 
 				return 1;
@@ -1845,6 +1850,7 @@ static int smsc95xx_rx_fixup(struct usbnet *dev, struct sk_buff *skb)
 			if (dev->net->features & NETIF_F_RXCSUM)
 				smsc95xx_rx_csum_offload(ax_skb);
 			skb_trim(ax_skb, ax_skb->len - 4); /* remove fcs */
+			if (truesize_mode)
 				ax_skb->truesize = size + sizeof(struct sk_buff);
 
 			usbnet_skb_return(dev, ax_skb);