[PATCH net] net: stmmac: remove disable_irq() from ->ndo_poll_controller()

[PATCH net] net: stmmac: remove disable_irq() from ->ndo_poll_controller()

[Remi Pommarel]

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

Commit [0] introcuded disable_hardirq() to address this situation, so
use it here to avoid above warning.

[0] 02cea395866 ("genirq: Provide disable_hardirq()")

Cc: <stable@vger.kernel.org>
Signed-off-by: Remi Pommarel <repk@triplefau.lt>
---
 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 4727f7be4f86..bbe509abc5dc 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -5958,8 +5958,8 @@ static void stmmac_poll_controller(struct net_device *dev)
 		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);
+		if (disable_hardirq(dev->irq))
+			stmmac_interrupt(dev->irq, dev);
 		enable_irq(dev->irq);
 	}
 }
-- 
2.40.0

Re: [PATCH net] net: stmmac: remove disable_irq() from ->ndo_poll_controller()

[Jakub Kicinski]

On Thu, 10 Aug 2023 10:37:16 +0200 Remi Pommarel wrote:
> diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> index 4727f7be4f86..bbe509abc5dc 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> @@ -5958,8 +5958,8 @@ static void stmmac_poll_controller(struct net_device *dev)
>  		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);
> +		if (disable_hardirq(dev->irq))
> +			stmmac_interrupt(dev->irq, dev);
>  		enable_irq(dev->irq);

Implementing .ndo_poll_controller is only needed if driver doesn't use
NAPI. This driver seems to use NAPI on all paths, AFAICT you can simply
delete this function completely.
-- 
pw-bot: cr

Re: [PATCH net] net: stmmac: remove disable_irq() from ->ndo_poll_controller()

[Remi Pommarel]

On Fri, Aug 11, 2023 at 06:20:25PM -0700, Jakub Kicinski wrote:
> On Thu, 10 Aug 2023 10:37:16 +0200 Remi Pommarel wrote:
> > diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> > index 4727f7be4f86..bbe509abc5dc 100644
> > --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> > +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> > @@ -5958,8 +5958,8 @@ static void stmmac_poll_controller(struct net_device *dev)
> >  		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);
> > +		if (disable_hardirq(dev->irq))
> > +			stmmac_interrupt(dev->irq, dev);
> >  		enable_irq(dev->irq);
> 
> Implementing .ndo_poll_controller is only needed if driver doesn't use
> NAPI. This driver seems to use NAPI on all paths, AFAICT you can simply
> delete this function completely.

Looks like since [0] you are right. Will send a new PATCH removing
stmmac_poll_controller.

Thanks.

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

-- 
Remi