[PATCH net v3 1/2] net/stmmac: Check for STMMAC_DOWN flag in all XDP paths

[Jakub Raczynski <j.raczynski@samsung.com>]

Currently STMMAC_DOWN flag is only set/cleared by stmmac_reset_subtask(),
to notify driver to stop processing of TX/RX frames. One of these processing
paths is for XDP, but it is only ever checked in stmmac_xdp_xmit(), which
leaves all other XDP paths vulnerable to processing data while interface is
restarting.

Make verification of STMMAC_DOWN flag consistent by applying check to
all XDP paths.

Fixes: 8b278a5b69a22 ("net: stmmac: Add support for XDP_REDIRECT action")
Co-developed-by: Chang-Sub Lee <cs0617.lee@samsung.com>
Signed-off-by: Chang-Sub Lee <cs0617.lee@samsung.com>
Signed-off-by: Jakub Raczynski <j.raczynski@samsung.com>
---
 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 2a0d7eff88d3..b9ffff001baf 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -5260,12 +5260,18 @@ static int stmmac_xdp_xmit_back(struct stmmac_priv *priv,
 				struct xdp_buff *xdp)
 {
 	bool zc = !!(xdp->rxq->mem.type == MEM_TYPE_XSK_BUFF_POOL);
-	struct xdp_frame *xdpf = xdp_convert_buff_to_frame(xdp);
+	struct xdp_frame *xdpf;
 	int cpu = smp_processor_id();
 	struct netdev_queue *nq;
 	int queue;
 	int res;
 
+	if (unlikely(test_bit(STMMAC_DOWN, &priv->state))) {
+		xsk_buff_free(xdp);
+		return STMMAC_XSK_CONSUMED;
+	}
+
+	xdpf = xdp_convert_buff_to_frame(xdp);
 	if (unlikely(!xdpf))
 		return STMMAC_XDP_CONSUMED;
 
@@ -5310,7 +5316,9 @@ static int __stmmac_xdp_run_prog(struct stmmac_priv *priv,
 		res = stmmac_xdp_xmit_back(priv, xdp);
 		break;
 	case XDP_REDIRECT:
-		if (xdp_do_redirect(priv->dev, xdp, prog) < 0)
+		if (unlikely(test_bit(STMMAC_DOWN, &priv->state)))
+			res = STMMAC_XDP_CONSUMED;
+		else if (xdp_do_redirect(priv->dev, xdp, prog) < 0)
 			res = STMMAC_XDP_CONSUMED;
 		else
 			res = STMMAC_XDP_REDIRECT;
-- 
2.34.1