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r8169: remove unneeded memory barrier in rtl_tx

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[ Upstream commit 3a689e34973e8717cd57991c6fcf527dc56062b5 ]

tp->dirty_tx isn't changed outside rtl_tx(). Therefore I see no need
to guarantee a specific order of reading tp->dirty_tx and tp->cur_tx.
Having said that we can remove the memory barrier.
In addition use READ_ONCE() when reading tp->cur_tx because it can
change in parallel to rtl_tx().

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Link: https://lore.kernel.org/r/2264563a-fa9e-11b0-2c42-31bc6b8e2790@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Stable-dep-of: c71e3a5cffd5 ("r8169: Fix possible ring buffer corruption on fragmented Tx packets.")
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Heiner Kallweit 2020-10-29 18:56:06 +01:00 committed by Ksawlii
parent 329eef5594
commit 703e09df9c
1 changed files with 1 additions and 2 deletions
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3
drivers/net/ethernet/realtek/r8169_main.c
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@ -4472,9 +4472,8 @@ static void rtl_tx(struct net_device *dev, struct rtl8169_private *tp,
unsigned int dirty_tx, tx_left, bytes_compl = 0, pkts_compl = 0; unsigned int dirty_tx, tx_left, bytes_compl = 0, pkts_compl = 0;
dirty_tx = tp->dirty_tx; dirty_tx = tp->dirty_tx;
smp_rmb();
for (tx_left = tp->cur_tx - dirty_tx; tx_left > 0; tx_left--) { for (tx_left = READ_ONCE(tp->cur_tx) - dirty_tx; tx_left; tx_left--) {
unsigned int entry = dirty_tx % NUM_TX_DESC; unsigned int entry = dirty_tx % NUM_TX_DESC;
struct sk_buff *skb = tp->tx_skb[entry].skb; struct sk_buff *skb = tp->tx_skb[entry].skb;
u32 status; u32 status;