[PATCH net-next v2] r8169: Use napi_schedule_irqoff()

[PATCH net-next v2] r8169: Use napi_schedule_irqoff()

[Matt Vollrath]

napi_schedule() masks hard interrupts while doing its work, which is
redundant when called from an interrupt handler where hard interrupts
are already masked. Use napi_schedule_irqoff() instead to bypass this
redundant masking. This is an optimization.

Tested on a Lenovo RTL8168h/8111h.

Signed-off-by: Matt Vollrath <tactii@gmail.com>
---
 drivers/net/ethernet/realtek/r8169_main.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/realtek/r8169_main.c b/drivers/net/ethernet/realtek/r8169_main.c
index 791277e750ba..4c0ad0de3410 100644
--- a/drivers/net/ethernet/realtek/r8169_main.c
+++ b/drivers/net/ethernet/realtek/r8169_main.c
@@ -4873,7 +4873,7 @@ static irqreturn_t rtl8169_interrupt(int irq, void *dev_instance)
 		phy_mac_interrupt(tp->phydev);
 
 	rtl_irq_disable(tp);
-	napi_schedule(&tp->napi);
+	napi_schedule_irqoff(&tp->napi);
 out:
 	rtl_ack_events(tp, status);
 
-- 
2.43.0

Changes:
v2:
* CC the maintainers, make the CI board green

Re: [PATCH net-next v2] r8169: Use napi_schedule_irqoff()

[Heiner Kallweit]

On 12.04.2026 03:40, Matt Vollrath wrote:
> napi_schedule() masks hard interrupts while doing its work, which is
> redundant when called from an interrupt handler where hard interrupts
> are already masked. Use napi_schedule_irqoff() instead to bypass this
> redundant masking. This is an optimization.
> 
> Tested on a Lenovo RTL8168h/8111h.
> 
> Signed-off-by: Matt Vollrath <tactii@gmail.com>
> ---
>  drivers/net/ethernet/realtek/r8169_main.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/net/ethernet/realtek/r8169_main.c b/drivers/net/ethernet/realtek/r8169_main.c
> index 791277e750ba..4c0ad0de3410 100644
> --- a/drivers/net/ethernet/realtek/r8169_main.c
> +++ b/drivers/net/ethernet/realtek/r8169_main.c
> @@ -4873,7 +4873,7 @@ static irqreturn_t rtl8169_interrupt(int irq, void *dev_instance)
>  		phy_mac_interrupt(tp->phydev);
>  
>  	rtl_irq_disable(tp);
> -	napi_schedule(&tp->napi);
> +	napi_schedule_irqoff(&tp->napi);
>  out:
>  	rtl_ack_events(tp, status);
>  

Not using napi_schedule_irqoff() here is intentional,
see 2734a24e6e5d18522fbf599135c59b82ec9b2c9e.

Re: [PATCH net-next v2] r8169: Use napi_schedule_irqoff()

[Matt Vollrath]

On 4/12/26 07:30, Heiner Kallweit wrote:
> On 12.04.2026 03:40, Matt Vollrath wrote:
>> diff --git a/drivers/net/ethernet/realtek/r8169_main.c b/drivers/net/ethernet/realtek/r8169_main.c
>> index 791277e750ba..4c0ad0de3410 100644
>> --- a/drivers/net/ethernet/realtek/r8169_main.c
>> +++ b/drivers/net/ethernet/realtek/r8169_main.c
>> @@ -4873,7 +4873,7 @@ static irqreturn_t rtl8169_interrupt(int irq, void *dev_instance)
>>   		phy_mac_interrupt(tp->phydev);
>>   
>>   	rtl_irq_disable(tp);
>> -	napi_schedule(&tp->napi);
>> +	napi_schedule_irqoff(&tp->napi);
>>   out:
>>   	rtl_ack_events(tp, status);
>>   
> 
> Not using napi_schedule_irqoff() here is intentional,
> see 2734a24e6e5d18522fbf599135c59b82ec9b2c9e.

I see, thank you Heiner. Seems like it could work if
legacy interrupts went to a separate handler, but not
worth the complexity for this small optimization.
mv

Re: [PATCH net-next v2] r8169: Use napi_schedule_irqoff()

[Matt Vollrath]

On 4/12/26 07:30, Heiner Kallweit wrote:
> On 12.04.2026 03:40, Matt Vollrath wrote:
>> diff --git a/drivers/net/ethernet/realtek/r8169_main.c b/drivers/net/ethernet/realtek/r8169_main.c
>> index 791277e750ba..4c0ad0de3410 100644
>> --- a/drivers/net/ethernet/realtek/r8169_main.c
>> +++ b/drivers/net/ethernet/realtek/r8169_main.c
>> @@ -4873,7 +4873,7 @@ static irqreturn_t rtl8169_interrupt(int irq, void *dev_instance)
>>   		phy_mac_interrupt(tp->phydev);
>>   
>>   	rtl_irq_disable(tp);
>> -	napi_schedule(&tp->napi);
>> +	napi_schedule_irqoff(&tp->napi);
>>   out:
>>   	rtl_ack_events(tp, status);
>>   
> 
> Not using napi_schedule_irqoff() here is intentional,
> see 2734a24e6e5d18522fbf599135c59b82ec9b2c9e.

It looks like forced threading was fixed after your fix
to mitigate the issue of forced threading not masking
interrupts.

see 81e2073c175b887398e5bca6c004efa89983f58d

If I understand correctly, this should make
napi_schedule_irqoff() safe in any interrupt handler.

Re: [PATCH net-next v2] r8169: Use napi_schedule_irqoff()

[Heiner Kallweit]

On 12.04.2026 15:51, Matt Vollrath wrote:
> On 4/12/26 07:30, Heiner Kallweit wrote:
>> On 12.04.2026 03:40, Matt Vollrath wrote:
>>> diff --git a/drivers/net/ethernet/realtek/r8169_main.c b/drivers/net/ethernet/realtek/r8169_main.c
>>> index 791277e750ba..4c0ad0de3410 100644
>>> --- a/drivers/net/ethernet/realtek/r8169_main.c
>>> +++ b/drivers/net/ethernet/realtek/r8169_main.c
>>> @@ -4873,7 +4873,7 @@ static irqreturn_t rtl8169_interrupt(int irq, void *dev_instance)
>>>           phy_mac_interrupt(tp->phydev);
>>>         rtl_irq_disable(tp);
>>> -    napi_schedule(&tp->napi);
>>> +    napi_schedule_irqoff(&tp->napi);
>>>   out:
>>>       rtl_ack_events(tp, status);
>>>   
>>
>> Not using napi_schedule_irqoff() here is intentional,
>> see 2734a24e6e5d18522fbf599135c59b82ec9b2c9e.
> 
> It looks like forced threading was fixed after your fix
> to mitigate the issue of forced threading not masking
> interrupts.
> 
> see 81e2073c175b887398e5bca6c004efa89983f58d
> 
> If I understand correctly, this should make
> napi_schedule_irqoff() safe in any interrupt handler.
> 

I think 8380c81d5c4fced6f4397795a5ae65758272bbfd needs to be
mentioned too, because only with this change your patch is safe
under PREEMPT_RT. Best extend the commit message based on our
discussion. With that one:
Reviewed-by: Heiner Kallweit <hkallweit1@gmail.com>