netdev - [PATCH net v2] r8169: don't advertise pause in jumbo mode

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Date:   Wed, 14 Apr 2021 10:47:10 +0200
From:   Heiner Kallweit <hkallweit1@...il.com>
To:     Jakub Kicinski <kuba@...nel.org>,
        David Miller <davem@...emloft.net>,
        Realtek linux nic maintainers <nic_swsd@...ltek.com>
Cc:     "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        "stable@...r.kernel.org" <stable@...r.kernel.org>,
        Roman Mamedov <rm+bko@...anrm.net>
Subject: [PATCH net v2] r8169: don't advertise pause in jumbo mode

It has been reported [0] that using pause frames in jumbo mode impacts
performance. There's no available chip documentation, but vendor
drivers r8168 and r8125 don't advertise pause in jumbo mode. So let's
do the same, according to Roman it fixes the issue.

[0] https://bugzilla.kernel.org/show_bug.cgi?id=212617

Fixes: 9cf9b84cc701 ("r8169: make use of phy_set_asym_pause")
Reported-by: Roman Mamedov <rm+bko@...anrm.net>
Tested-by: Roman Mamedov <rm+bko@...anrm.net>
Signed-off-by: Heiner Kallweit <hkallweit1@...il.com>
Cc: stable@...r.kernel.org
---
This patch doesn't apply cleanly on some kernel versions, but the needed
changes are trivial.
v2: added cc stable in sign-off area
---
 drivers/net/ethernet/realtek/r8169_main.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/realtek/r8169_main.c b/drivers/net/ethernet/realtek/r8169_main.c
index 1b48084f2..7d02bab1c 100644
--- a/drivers/net/ethernet/realtek/r8169_main.c
+++ b/drivers/net/ethernet/realtek/r8169_main.c
@@ -2386,6 +2386,13 @@ static void rtl_jumbo_config(struct rtl8169_private *tp)
 
 	if (pci_is_pcie(tp->pci_dev) && tp->supports_gmii)
 		pcie_set_readrq(tp->pci_dev, readrq);
+
+	/* Chip doesn't support pause in jumbo mode */
+	linkmode_mod_bit(ETHTOOL_LINK_MODE_Pause_BIT,
+			 tp->phydev->advertising, !jumbo);
+	linkmode_mod_bit(ETHTOOL_LINK_MODE_Asym_Pause_BIT,
+			 tp->phydev->advertising, !jumbo);
+	phy_start_aneg(tp->phydev);
 }
 
 DECLARE_RTL_COND(rtl_chipcmd_cond)
@@ -4647,8 +4654,6 @@ static int r8169_phy_connect(struct rtl8169_private *tp)
 	if (!tp->supports_gmii)
 		phy_set_max_speed(phydev, SPEED_100);
 
-	phy_support_asym_pause(phydev);
-
 	phy_attached_info(phydev);
 
 	return 0;
-- 
2.31.1