Re: [PATCH] net: phy: Move interrupt check from phy_check to phy_interrupt

From: Sergei Shtylyov
Date: Thu Mar 08 2018 - 14:58:08 EST


On 03/08/2018 10:41 PM, Sergei Shtylyov wrote:

>> If multiple phys share the same interrupt (e.g. a multi-phy chip),
>> the first device registered is the only one checked as phy_interrupt
>> will always return IRQ_HANDLED if the first phydev is not halted.
>> Move the interrupt check into phy_interrupt and, if it was not this
>> phydev, return IRQ_NONE to allow other devices on this irq a chance
>> to check if it was their interrupt.
>
> Hm, looking at kernel/irq/handle.c, all registered IRQ handlers are always
> called regardless of their results. Care to explain?
>
>> Signed-off-by: Brad Mouring <brad.mouring@xxxxxx>
>> ---
>> drivers/net/phy/phy.c | 16 ++++++----------
>> 1 file changed, 6 insertions(+), 10 deletions(-)
>>
>> diff --git a/drivers/net/phy/phy.c b/drivers/net/phy/phy.c
>> index e3e29c2b028b..ff1aa815568f 100644
>> --- a/drivers/net/phy/phy.c
>> +++ b/drivers/net/phy/phy.c
>> @@ -632,6 +632,12 @@ static irqreturn_t phy_interrupt(int irq, void *phy_dat)
>> if (PHY_HALTED == phydev->state)
>> return IRQ_NONE; /* It can't be ours. */
>>
>> + if (phy_interrupt_is_valid(phydev)) {
>
> Always true in this context, no?
>
>> + if (phydev->drv->did_interrupt &&
>> + !phydev->drv->did_interrupt(phydev))
>
> I don't think we can do this in the interrupt context as this function *will*
> read from MDIO... I think that was the reason why IRQ handling is done in the
> thread context...

Ah, we're already in a thread context here! Forgot about it...

> [...]

MBR, Sergei