From: Ray Jui <ray.jui@broadcom.com>
Date: Fri, 1 Apr 2022 20:21:12 -0400
Subject: bnxt_en: Prevent XDP redirect from running when stopping TX queue
Patch-mainline: v5.18-rc2
Git-commit: 27d4073f8d9af0340362554414f4961643a4f4de
References: git-fixes

Add checks in the XDP redirect callback to prevent XDP from running when
the TX ring is undergoing shutdown.

Also remove redundant checks in the XDP redirect callback to validate the
txr and the flag that indicates the ring supports XDP. The modulo
arithmetic on 'tx_nr_rings_xdp' already guarantees the derived TX
ring is an XDP ring.  txr is also guaranteed to be valid after checking
BNXT_STATE_OPEN and within RCU grace period.

Fixes: f18c2b77b2e4 ("bnxt_en: optimized XDP_REDIRECT support")
Reviewed-by: Vladimir Olovyannikov <vladimir.olovyannikov@broadcom.com>
Signed-off-by: Ray Jui <ray.jui@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

--- a/drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.c
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.c
@@ -229,14 +229,16 @@ int bnxt_xdp_xmit(struct net_device *dev
 	ring = smp_processor_id() % bp->tx_nr_rings_xdp;
 	txr = &bp->tx_ring[ring];
 
+	if (READ_ONCE(txr->dev_state) == BNXT_DEV_STATE_CLOSING)
+		return -EINVAL;
+
 	if (static_branch_unlikely(&bnxt_xdp_locking_key))
 		spin_lock(&txr->xdp_tx_lock);
 
 	for (i = 0; i < num_frames; i++) {
 		struct xdp_frame *xdp = frames[i];
 
-		if (!txr || !bnxt_tx_avail(bp, txr) ||
-		    !(bp->bnapi[ring]->flags & BNXT_NAPI_FLAG_XDP))
+		if (!bnxt_tx_avail(bp, txr))
 			break;
 
 		mapping = dma_map_single(&pdev->dev, xdp->data, xdp->len,