r8169: use READ_ONCE in rtl_tx_slots_avail

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
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Heiner Kallweit 2020-11-11 22:14:27 +01:00 committed by Jakub Kicinski
parent 2caf08e757
commit 95f3c5458d
1 changed files with 2 additions and 1 deletions

View File

@ -4144,7 +4144,8 @@ 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;