Re: [PATCH] net: mdio-gpio: support access that may sleep

[Sergei Shtylyov]

On 04/24/2015 06:56 PM, Florian Fainelli wrote:

> > > Some systems using mdio-gpio may use gpio on message based busses, which
> > > require sleeping (e.g. gpio from an I2C I/O expander).

> > > Since this driver does not use IRQ handler, it is safe to use the
> > > _cansleep suffixed gpio accessors.

> > > Signed-off-by: Vivien Didelot <vivien.didelot@xxxxxxxxxxxxxxxxxxxx>

> > Since this is down underneath the layer of an MII bus, you cannot
> > universally say that these routines are always called in a sleepable
> > context.

> > The PHY layer, and the driver itself above that, might call these
> > routines from timers, interruptes etc.

> The PHY library calls these routines from its state machine workqueue
> for that reason, or from process context (when invoked via ethtool
> ioctl). The only special case is phy_mac_interrupt() which is callable
> from interrupt context,

   It is not (as we have discussed recently) -- cancel_work_sync() may sleep.

WBR, Sergei

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