[PATCH AUTOSEL 5.4 036/130] r8169: use READ_ONCE in rtl_tx_slots_avail
From: Sasha Levin <sashal@kernel.org>
Date: 2020-12-23 02:19:59
Also in:
lkml, stable
Subsystem:
8169 10/100/1000 gigabit ethernet driver, networking drivers, the rest · Maintainers:
Heiner Kallweit, Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
From: Heiner Kallweit <hkallweit1@gmail.com> [ Upstream commit 95f3c5458dfa5856bb110e31d156e00d894d0134 ] tp->dirty_tx and tp->cur_tx may be changed by a racing rtl_tx() or rtl8169_start_xmit(). Use READ_ONCE() to annotate the races and ensure that the compiler doesn't use cached values. Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com> Link: https://lore.kernel.org/r/5676fee3-f6b4-84f2-eba5-c64949a371ad@gmail.com (local) Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> --- drivers/net/ethernet/realtek/r8169_main.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/net/ethernet/realtek/r8169_main.c b/drivers/net/ethernet/realtek/r8169_main.c
index fd5adb0c54d29..fca8252b4f21d 100644
--- a/drivers/net/ethernet/realtek/r8169_main.c
+++ b/drivers/net/ethernet/realtek/r8169_main.c@@ -5856,7 +5856,8 @@ static bool rtl8169_tso_csum_v2(struct rtl8169_private *tp, static bool rtl_tx_slots_avail(struct rtl8169_private *tp, unsigned int nr_frags) { - unsigned int slots_avail = tp->dirty_tx + NUM_TX_DESC - tp->cur_tx; + unsigned int slots_avail = READ_ONCE(tp->dirty_tx) + NUM_TX_DESC + - READ_ONCE(tp->cur_tx); /* A skbuff with nr_frags needs nr_frags+1 entries in the tx queue */ return slots_avail > nr_frags;
--
2.27.0