Commit 95f3c545 authored Nov 11, 2020 by Heiner Kallweit Committed by Jakub Kicinski Nov 13, 2020

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>

parent 2caf08e7

drivers/net/ethernet/realtek/r8169_main.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -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;

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