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From:   Remi Pommarel <repk@triplefau.lt>
To:     Alexandre Torgue <alexandre.torgue@foss.st.com>,
        Jose Abreu <joabreu@synopsys.com>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc:     netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
        Remi Pommarel <repk@triplefau.lt>, stable@vger.kernel.org
Subject: [PATCH net] net: stmmac: remove unneeded stmmac_poll_controller
Date:   Thu, 31 Aug 2023 14:00:04 +0200
Message-Id: <20230831120004.6919-1-repk@triplefau.lt>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

Using netconsole netpoll_poll_dev could be called from interrupt
context, thus using disable_irq() would cause the following kernel
warning with CONFIG_DEBUG_ATOMIC_SLEEP enabled:

  BUG: sleeping function called from invalid context at kernel/irq/manage.c:137
  in_atomic(): 1, irqs_disabled(): 128, non_block: 0, pid: 10, name: ksoftirqd/0
  CPU: 0 PID: 10 Comm: ksoftirqd/0 Tainted: G        W         5.15.42-00075-g816b502b2298-dirty #117
  Hardware name: aml (r1) (DT)
  Call trace:
   dump_backtrace+0x0/0x270
   show_stack+0x14/0x20
   dump_stack_lvl+0x8c/0xac
   dump_stack+0x18/0x30
   ___might_sleep+0x150/0x194
   __might_sleep+0x64/0xbc
   synchronize_irq+0x8c/0x150
   disable_irq+0x2c/0x40
   stmmac_poll_controller+0x140/0x1a0
   netpoll_poll_dev+0x6c/0x220
   netpoll_send_skb+0x308/0x390
   netpoll_send_udp+0x418/0x760
   write_msg+0x118/0x140 [netconsole]
   console_unlock+0x404/0x500
   vprintk_emit+0x118/0x250
   dev_vprintk_emit+0x19c/0x1cc
   dev_printk_emit+0x90/0xa8
   __dev_printk+0x78/0x9c
   _dev_warn+0xa4/0xbc
   ath10k_warn+0xe8/0xf0 [ath10k_core]
   ath10k_htt_txrx_compl_task+0x790/0x7fc [ath10k_core]
   ath10k_pci_napi_poll+0x98/0x1f4 [ath10k_pci]
   __napi_poll+0x58/0x1f4
   net_rx_action+0x504/0x590
   _stext+0x1b8/0x418
   run_ksoftirqd+0x74/0xa4
   smpboot_thread_fn+0x210/0x3c0
   kthread+0x1fc/0x210
   ret_from_fork+0x10/0x20

Since [0] .ndo_poll_controller is only needed if driver doesn't or
partially use NAPI. Because stmmac does so, stmmac_poll_controller
can be removed fixing the above warning.

[0] commit ac3d9dd034e5 ("netpoll: make ndo_poll_controller() optional")

Cc: <stable@vger.kernel.org> # 5.15.x
Signed-off-by: Remi Pommarel <repk@triplefau.lt>
---
 .../net/ethernet/stmicro/stmmac/stmmac_main.c | 30 -------------------
 1 file changed, 30 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 4727f7be4f86..9b5c0ebf0519 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -5938,33 +5938,6 @@ static irqreturn_t stmmac_msi_intr_rx(int irq, void *data)
 	return IRQ_HANDLED;
 }
 
-#ifdef CONFIG_NET_POLL_CONTROLLER
-/* Polling receive - used by NETCONSOLE and other diagnostic tools
- * to allow network I/O with interrupts disabled.
- */
-static void stmmac_poll_controller(struct net_device *dev)
-{
-	struct stmmac_priv *priv = netdev_priv(dev);
-	int i;
-
-	/* If adapter is down, do nothing */
-	if (test_bit(STMMAC_DOWN, &priv->state))
-		return;
-
-	if (priv->plat->multi_msi_en) {
-		for (i = 0; i < priv->plat->rx_queues_to_use; i++)
-			stmmac_msi_intr_rx(0, &priv->dma_conf.rx_queue[i]);
-
-		for (i = 0; i < priv->plat->tx_queues_to_use; i++)
-			stmmac_msi_intr_tx(0, &priv->dma_conf.tx_queue[i]);
-	} else {
-		disable_irq(dev->irq);
-		stmmac_interrupt(dev->irq, dev);
-		enable_irq(dev->irq);
-	}
-}
-#endif
-
 /**
  *  stmmac_ioctl - Entry point for the Ioctl
  *  @dev: Device pointer.
@@ -6800,9 +6773,6 @@ static const struct net_device_ops stmmac_netdev_ops = {
 	.ndo_eth_ioctl = stmmac_ioctl,
 	.ndo_setup_tc = stmmac_setup_tc,
 	.ndo_select_queue = stmmac_select_queue,
-#ifdef CONFIG_NET_POLL_CONTROLLER
-	.ndo_poll_controller = stmmac_poll_controller,
-#endif
 	.ndo_set_mac_address = stmmac_set_mac_address,
 	.ndo_vlan_rx_add_vid = stmmac_vlan_rx_add_vid,
 	.ndo_vlan_rx_kill_vid = stmmac_vlan_rx_kill_vid,
-- 
2.40.0