| Message ID | 2264563a-fa9e-11b0-2c42-31bc6b8e2790@gmail.com (mailing list archive) |
|---|---|
| State | Not Applicable |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net-next] r8169: remove unneeded memory barrier in rtl_tx | expand |
On Thu, 29 Oct 2020 18:56:06 +0100 Heiner Kallweit wrote: > 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> Applied, thanks!
diff --git a/drivers/net/ethernet/realtek/r8169_main.c b/drivers/net/ethernet/realtek/r8169_main.c index b6c11aaa5..75df476c6 100644 --- a/drivers/net/ethernet/realtek/r8169_main.c +++ b/drivers/net/ethernet/realtek/r8169_main.c @@ -4364,9 +4364,8 @@ static void rtl_tx(struct net_device *dev, struct rtl8169_private *tp, unsigned int dirty_tx, tx_left, bytes_compl = 0, pkts_compl = 0; 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; struct sk_buff *skb = tp->tx_skb[entry].skb; u32 status;
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> --- drivers/net/ethernet/realtek/r8169_main.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)