From 794867ee6730fe3f0d419d3911f35a725cafe3a8 Mon Sep 17 00:00:00 2001 From: Heiner Kallweit Date: Mon, 20 Apr 2020 22:52:59 +0200 Subject: [PATCH] r8169: change wmb to smb_wmb in rtl8169_start_xmit A barrier is needed here to ensure that rtl_tx sees the descriptor changes (DescOwn set) before the updated tp->cur_tx value. Else it may wrongly assume that the transfer has been finished already. For this purpose smp_wmb() is sufficient. No separate barrier is needed for ordering the descriptor changes with the MMIO doorbell write. The needed barrier is included in the non-relaxed writel() used by rtl8169_doorbell(). Signed-off-by: Heiner Kallweit Signed-off-by: David S. Miller --- drivers/net/ethernet/realtek/r8169_main.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/net/ethernet/realtek/r8169_main.c b/drivers/net/ethernet/realtek/r8169_main.c index b8cc064ee9f5..b7a2853e7396 100644 --- a/drivers/net/ethernet/realtek/r8169_main.c +++ b/drivers/net/ethernet/realtek/r8169_main.c @@ -4249,8 +4249,8 @@ static netdev_tx_t rtl8169_start_xmit(struct sk_buff *skb, txd_first->opts1 |= cpu_to_le32(DescOwn | FirstFrag); - /* Force all memory writes to complete before notifying device */ - wmb(); + /* rtl_tx needs to see descriptor changes before updated tp->cur_tx */ + smp_wmb(); tp->cur_tx += frags + 1;