netdev - [PATCH net 12/15] bnx2x: remove ndo_poll

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Date:   Fri, 21 Sep 2018 15:27:49 -0700
From:   Eric Dumazet <edumazet@...gle.com>
To:     "David S . Miller" <davem@...emloft.net>
Cc:     netdev <netdev@...r.kernel.org>,
        Eric Dumazet <edumazet@...gle.com>,
        Michael Chan <michael.chan@...adcom.com>,
        Ariel Elior <ariel.elior@...ium.com>,
        Eric Dumazet <eric.dumazet@...il.com>,
        Tariq Toukan <tariqt@...lanox.com>,
        Saeed Mahameed <saeedm@...lanox.com>,
        Jeff Kirsher <jeffrey.t.kirsher@...el.com>,
        Jakub Kicinski <jakub.kicinski@...ronome.com>,
        Song Liu <songliubraving@...com>,
        Jay Vosburgh <j.vosburgh@...il.com>,
        Veaceslav Falico <vfalico@...il.com>,
        Andy Gospodarek <andy@...yhouse.net>
Subject: [PATCH net 12/15] bnx2x: remove ndo_poll_controller

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.

bnx2x 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@...gle.com>
Cc: Ariel Elior <ariel.elior@...ium.com>
---
 drivers/net/ethernet/broadcom/bnx2x/bnx2x_main.c | 16 ----------------
 1 file changed, 16 deletions(-)

diff --git a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_main.c b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_main.c
index 71362b7f60402545c3b4aa2bc391a1e2d3cd7f7f..fcc2328bb0d953e797c49699b11e5e5956a0d583 100644
--- a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_main.c
+++ b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_main.c
@@ -12894,19 +12894,6 @@ static int bnx2x_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
 	}
 }
 
-#ifdef CONFIG_NET_POLL_CONTROLLER
-static void poll_bnx2x(struct net_device *dev)
-{
-	struct bnx2x *bp = netdev_priv(dev);
-	int i;
-
-	for_each_eth_queue(bp, i) {
-		struct bnx2x_fastpath *fp = &bp->fp[i];
-		napi_schedule(&bnx2x_fp(bp, fp->index, napi));
-	}
-}
-#endif
-
 static int bnx2x_validate_addr(struct net_device *dev)
 {
 	struct bnx2x *bp = netdev_priv(dev);
@@ -13113,9 +13100,6 @@ static const struct net_device_ops bnx2x_netdev_ops = {
 	.ndo_tx_timeout		= bnx2x_tx_timeout,
 	.ndo_vlan_rx_add_vid	= bnx2x_vlan_rx_add_vid,
 	.ndo_vlan_rx_kill_vid	= bnx2x_vlan_rx_kill_vid,
-#ifdef CONFIG_NET_POLL_CONTROLLER
-	.ndo_poll_controller	= poll_bnx2x,
-#endif
 	.ndo_setup_tc		= __bnx2x_setup_tc,
 #ifdef CONFIG_BNX2X_SRIOV
 	.ndo_set_vf_mac		= bnx2x_set_vf_mac,
-- 
2.19.0.444.g18242da7ef-goog