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From: Jeff Evanson <jeff.evanson@gmail.com>
To: Jesse Brandeburg <jesse.brandeburg@intel.com>,
	Tony Nguyen <anthony.l.nguyen@intel.com>,
	"David S. Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>,
	Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Jesper Dangaard Brouer <hawk@kernel.org>,
	John Fastabend <john.fastabend@gmail.com>,
	intel-wired-lan@lists.osuosl.org, netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org, bpf@vger.kernel.org
Cc: jeff.evanson@qsc.com, jeff.evanson@gmail.com
Subject: [PATCH 1/2] Fix race in igc_xdp_xmit_zc
Date: Fri, 15 Apr 2022 15:04:21 -0600	[thread overview]
Message-ID: <20220415210421.11217-1-jeff.evanson@qsc.com> (raw)

in igc_xdp_xmit_zc, initialize next_to_use while holding the netif_tx_lock
to prevent racing with other users of the tx ring

Signed-off-by: Jeff Evanson <jeff.evanson@qsc.com>
---
 drivers/net/ethernet/intel/igc/igc_main.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/intel/igc/igc_main.c b/drivers/net/ethernet/intel/igc/igc_main.c
index 1c00ee310c19..a36a18c84aeb 100644
--- a/drivers/net/ethernet/intel/igc/igc_main.c
+++ b/drivers/net/ethernet/intel/igc/igc_main.c
@@ -2598,7 +2598,7 @@ static void igc_xdp_xmit_zc(struct igc_ring *ring)
 	struct netdev_queue *nq = txring_txq(ring);
 	union igc_adv_tx_desc *tx_desc = NULL;
 	int cpu = smp_processor_id();
-	u16 ntu = ring->next_to_use;
+	u16 ntu;
 	struct xdp_desc xdp_desc;
 	u16 budget;
 
@@ -2607,6 +2607,8 @@ static void igc_xdp_xmit_zc(struct igc_ring *ring)
 
 	__netif_tx_lock(nq, cpu);
 
+	ntu = ring->next_to_use;
+
 	budget = igc_desc_unused(ring);
 
 	while (xsk_tx_peek_desc(pool, &xdp_desc) && budget--) {
-- 
2.17.1


             reply	other threads:[~2022-04-15 21:06 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-04-15 21:04 Jeff Evanson [this message]
2022-04-18 17:39 ` [PATCH 1/2] Fix race in igc_xdp_xmit_zc Vinicius Costa Gomes
2022-04-20 10:37 ` [Intel-wired-lan] " Alexander Lobakin

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