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

From: Sergei Shtylyov
Date: Thu Mar 08 2018 - 14:46:51 EST


Hello!

On 03/08/2018 01:50 AM, Brad Mouring 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...

> + return IRQ_NONE;
> + }
> +
> phy_change(phydev);
>
> return IRQ_HANDLED;
[...]

MBR, Sergei