Commit 8d520b4d authored by Heiner Kallweit's avatar Heiner Kallweit Committed by Jakub Kicinski
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r8169: work around RTL8125 UDP hw bug 

It was reported that on RTL8125 network breaks under heavy UDP load,
e.g. torrent traffic ([0], from comment 27). Realtek confirmed a hw bug
and provided me with a test version of the r8125 driver including a
workaround. Tests confirmed that the workaround fixes the issue.
I modified the original version of the workaround to meet mainline
code style.

[0] https://bugzilla.kernel.org/show_bug.cgi?id=209839



v2:
- rebased to net
v3:
- make rtl_skb_is_udp() more robust and use skb_header_pointer()
  to access the ip(v6) header
v4:
- remove dependency on ptp_classify.h
- replace magic number with offsetof(struct udphdr, len)

Fixes: f1bce4ad ("r8169: add support for RTL8125")
Tested-by: default avatarxplo <xplo.bn@gmail.com>
Signed-off-by: default avatarHeiner Kallweit <hkallweit1@gmail.com>
Acked-by: default avatarWillem de Bruijn <willemb@google.com>
Link: https://lore.kernel.org/r/6e453d49-1801-e6de-d5f7-d7e6c7526c8f@gmail.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 01365633

drivers/net/ethernet/realtek/r8169_main.c

+65 −6
Original line number Diff line number Diff line
@@ -4046,17 +4046,72 @@ static int rtl8169_xmit_frags(struct rtl8169_private *tp, struct sk_buff *skb, 
	return -EIO;

}



static bool rtl_test_hw_pad_bug(struct rtl8169_private *tp)

static bool rtl_skb_is_udp(struct sk_buff *skb)

{

	int no = skb_network_offset(skb);

	struct ipv6hdr *i6h, _i6h;

	struct iphdr *ih, _ih;



	switch (vlan_get_protocol(skb)) {

	case htons(ETH_P_IP):

		ih = skb_header_pointer(skb, no, sizeof(_ih), &_ih);

		return ih && ih->protocol == IPPROTO_UDP;

	case htons(ETH_P_IPV6):

		i6h = skb_header_pointer(skb, no, sizeof(_i6h), &_i6h);

		return i6h && i6h->nexthdr == IPPROTO_UDP;

	default:

		return false;

	}

}



#define RTL_MIN_PATCH_LEN	47



/* see rtl8125_get_patch_pad_len() in r8125 vendor driver */

static unsigned int rtl8125_quirk_udp_padto(struct rtl8169_private *tp,

					    struct sk_buff *skb)

{

	unsigned int padto = 0, len = skb->len;



	if (rtl_is_8125(tp) && len < 128 + RTL_MIN_PATCH_LEN &&

	    rtl_skb_is_udp(skb) && skb_transport_header_was_set(skb)) {

		unsigned int trans_data_len = skb_tail_pointer(skb) -

					      skb_transport_header(skb);



		if (trans_data_len >= offsetof(struct udphdr, len) &&

		    trans_data_len < RTL_MIN_PATCH_LEN) {

			u16 dest = ntohs(udp_hdr(skb)->dest);



			/* dest is a standard PTP port */

			if (dest == 319 || dest == 320)

				padto = len + RTL_MIN_PATCH_LEN - trans_data_len;

		}



		if (trans_data_len < sizeof(struct udphdr))

			padto = max_t(unsigned int, padto,

				      len + sizeof(struct udphdr) - trans_data_len);

	}



	return padto;

}



static unsigned int rtl_quirk_packet_padto(struct rtl8169_private *tp,

					   struct sk_buff *skb)

{

	unsigned int padto;



	padto = rtl8125_quirk_udp_padto(tp, skb);



	switch (tp->mac_version) {

	case RTL_GIGA_MAC_VER_34:

	case RTL_GIGA_MAC_VER_60:

	case RTL_GIGA_MAC_VER_61:

	case RTL_GIGA_MAC_VER_63:

		return true;

		padto = max_t(unsigned int, padto, ETH_ZLEN);

	default:

		return false;

		break;

	}



	return padto;

}



static void rtl8169_tso_csum_v1(struct sk_buff *skb, u32 *opts)
@@ -4128,9 +4183,10 @@ static bool rtl8169_tso_csum_v2(struct rtl8169_private *tp, 


		opts[1] |= transport_offset << TCPHO_SHIFT;

	} else {

		if (unlikely(skb->len < ETH_ZLEN && rtl_test_hw_pad_bug(tp)))

			/* eth_skb_pad would free the skb on error */

			return !__skb_put_padto(skb, ETH_ZLEN, false);

		unsigned int padto = rtl_quirk_packet_padto(tp, skb);



		/* skb_padto would free the skb on error */

		return !__skb_put_padto(skb, padto, false);

	}



	return true;
@@ -4307,6 +4363,9 @@ static netdev_features_t rtl8169_features_check(struct sk_buff *skb, 
		if (skb->len < ETH_ZLEN)

			features &= ~NETIF_F_CSUM_MASK;



		if (rtl_quirk_packet_padto(tp, skb))

			features &= ~NETIF_F_CSUM_MASK;



		if (transport_offset > TCPHO_MAX &&

		    rtl_chip_supports_csum_v2(tp))

			features &= ~NETIF_F_CSUM_MASK;