From: Eric Dumazet <edumazet@google.com>
Date: Fri, 21 Sep 2018 15:27:50 -0700
Subject: bnxt: remove ndo_poll_controller
Patch-mainline: v4.19-rc6
Git-commit: 58e0e22bff638055278ea73e34d0d07a95260790
References: bsc#1104745 FATE#325918

As diagnosed by Song Liu, ndo_poll_controller() can
be very dangerous on loaded hosts, since the cpu
calling ndo_poll_controller() might steal all NAPI
contexts (for all RX/TX queues of the NIC). This capture
can last for unlimited amount of time, since one
cpu is generally not able to drain all the queues under load.

bnxt uses NAPI for TX completions, so we better let core
networking stack call the napi->poll() to avoid the capture.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: 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.c |   18 ------------------
 1 file changed, 18 deletions(-)

--- a/drivers/net/ethernet/broadcom/bnxt/bnxt.c
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
@@ -7672,21 +7672,6 @@ static void bnxt_tx_timeout(struct net_d
 	bnxt_queue_sp_work(bp);
 }
 
-#ifdef CONFIG_NET_POLL_CONTROLLER
-static void bnxt_poll_controller(struct net_device *dev)
-{
-	struct bnxt *bp = netdev_priv(dev);
-	int i;
-
-	/* Only process tx rings/combined rings in netpoll mode. */
-	for (i = 0; i < bp->tx_nr_rings; i++) {
-		struct bnxt_tx_ring_info *txr = &bp->tx_ring[i];
-
-		napi_schedule(&txr->bnapi->napi);
-	}
-}
-#endif
-
 static void bnxt_timer(unsigned long data)
 {
 	struct bnxt *bp = (struct bnxt *)data;
@@ -8520,9 +8505,6 @@ static const struct net_device_ops bnxt_
 	.ndo_set_vf_spoofchk	= bnxt_set_vf_spoofchk,
 	.ndo_set_vf_trust	= bnxt_set_vf_trust,
 #endif
-#ifdef CONFIG_NET_POLL_CONTROLLER
-	.ndo_poll_controller	= bnxt_poll_controller,
-#endif
 	.ndo_setup_tc           = bnxt_setup_tc,
 #ifdef CONFIG_RFS_ACCEL
 	.ndo_rx_flow_steer	= bnxt_rx_flow_steer,