netdev - [PATCH net 05/15] fm10k: remove ndo_poll

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Message-Id: <20180921222752.101307-6-edumazet@google.com>
Date:   Fri, 21 Sep 2018 15:27:42 -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 05/15] fm10k: 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
lasts for unlimited amount of time, since one
cpu is generally not able to drain all the queues under load.

fm10k 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: Jeff Kirsher <jeffrey.t.kirsher@...el.com>
---
 drivers/net/ethernet/intel/fm10k/fm10k.h      |  3 ---
 .../net/ethernet/intel/fm10k/fm10k_netdev.c   |  3 ---
 drivers/net/ethernet/intel/fm10k/fm10k_pci.c  | 22 -------------------
 3 files changed, 28 deletions(-)

diff --git a/drivers/net/ethernet/intel/fm10k/fm10k.h b/drivers/net/ethernet/intel/fm10k/fm10k.h
index a903a0ba45e180c39e99c6b6a0726291203b1f91..7d42582ed48dc36f3da8b6b670d1c4f8847ffa9b 100644
--- a/drivers/net/ethernet/intel/fm10k/fm10k.h
+++ b/drivers/net/ethernet/intel/fm10k/fm10k.h
@@ -504,9 +504,6 @@ void fm10k_update_stats(struct fm10k_intfc *interface);
 void fm10k_service_event_schedule(struct fm10k_intfc *interface);
 void fm10k_macvlan_schedule(struct fm10k_intfc *interface);
 void fm10k_update_rx_drop_en(struct fm10k_intfc *interface);
-#ifdef CONFIG_NET_POLL_CONTROLLER
-void fm10k_netpoll(struct net_device *netdev);
-#endif
 
 /* Netdev */
 struct net_device *fm10k_alloc_netdev(const struct fm10k_info *info);
diff --git a/drivers/net/ethernet/intel/fm10k/fm10k_netdev.c b/drivers/net/ethernet/intel/fm10k/fm10k_netdev.c
index 929f538d28bc03a391340ebf6cc531b03f92b7a3..538a8467f43413f97bbf477053ba8e93560e2bcf 100644
--- a/drivers/net/ethernet/intel/fm10k/fm10k_netdev.c
+++ b/drivers/net/ethernet/intel/fm10k/fm10k_netdev.c
@@ -1648,9 +1648,6 @@ static const struct net_device_ops fm10k_netdev_ops = {
 	.ndo_udp_tunnel_del	= fm10k_udp_tunnel_del,
 	.ndo_dfwd_add_station	= fm10k_dfwd_add_station,
 	.ndo_dfwd_del_station	= fm10k_dfwd_del_station,
-#ifdef CONFIG_NET_POLL_CONTROLLER
-	.ndo_poll_controller	= fm10k_netpoll,
-#endif
 	.ndo_features_check	= fm10k_features_check,
 };
 
diff --git a/drivers/net/ethernet/intel/fm10k/fm10k_pci.c b/drivers/net/ethernet/intel/fm10k/fm10k_pci.c
index 15071e4adb98c9924ab2e9a17c7f616f23104bd0..c859ababeed50e030baf7cb7041fbd20916c2265 100644
--- a/drivers/net/ethernet/intel/fm10k/fm10k_pci.c
+++ b/drivers/net/ethernet/intel/fm10k/fm10k_pci.c
@@ -1210,28 +1210,6 @@ static irqreturn_t fm10k_msix_mbx_vf(int __always_unused irq, void *data)
 	return IRQ_HANDLED;
 }
 
-#ifdef CONFIG_NET_POLL_CONTROLLER
-/**
- *  fm10k_netpoll - A Polling 'interrupt' handler
- *  @netdev: network interface device structure
- *
- *  This is used by netconsole to send skbs without having to re-enable
- *  interrupts. It's not called while the normal interrupt routine is executing.
- **/
-void fm10k_netpoll(struct net_device *netdev)
-{
-	struct fm10k_intfc *interface = netdev_priv(netdev);
-	int i;
-
-	/* if interface is down do nothing */
-	if (test_bit(__FM10K_DOWN, interface->state))
-		return;
-
-	for (i = 0; i < interface->num_q_vectors; i++)
-		fm10k_msix_clean_rings(0, interface->q_vector[i]);
-}
-
-#endif
 #define FM10K_ERR_MSG(type) case (type): error = #type; break
 static void fm10k_handle_fault(struct fm10k_intfc *interface, int type,
 			       struct fm10k_fault *fault)
-- 
2.19.0.444.g18242da7ef-goog