> -----Original Message-----
> From: John Williams [mailto:john.willi...@petalogix.com]
> Sent: Tuesday, February 09, 2010 3:30 PM
> To: John Linn
> Cc: net...@vger.kernel.org; linuxppc-...@ozlabs.org; jgar...@pobox.com;
> grant.lik...@secretlab.ca;
> jwbo...@linux.vnet.ibm.com; Sadanand Mutyala
> Subject: Re: [PATCH] [V3] net: emaclite: adding MDIO and phy lib support
>
> Hi John,
>
> Sorry If I'm painting bike-sheds here, just one tiny tweak might be in
> order to standardise your mutex_unlock exit path:
>
> > +static int xemaclite_mdio_read(struct mii_bus *bus, int phy_id, int reg)
> > +{
> > + struct net_local *lp = bus->priv;
> > + u32 ctrl_reg;
> > + u32 rc;
> > +
> > + mutex_lock(&lp->mdio_mutex);
> > +
> > + if (xemaclite_mdio_wait(lp)) {
> > + mutex_unlock(&lp->mdio_mutex);
> > + return -ETIMEDOUT;
> > + }
>
> [snip]
>
>
> > + if (xemaclite_mdio_wait(lp)) {
> > + mutex_unlock(&lp->mdio_mutex);
> > + return -ETIMEDOUT;
> > + }
>
> [snip]
>
>
> > + dev_dbg(&lp->ndev->dev,
> > + "xemaclite_mdio_read(phy_id=%i, reg=%x) == %x\n",
> > + phy_id, reg, rc);
> > +
> > + return rc;
>
> Can this be better expressed like this:
>
> my_func() {
> mutex_lock()
> ..
>
> if(some error) {
> rc=-ETIMEDOUT;
> goto out_unlock;
> }
> ...
>
> /* success path */
> rc=0;
> ..
> out_unlock:
> mutex_unlock()
> return rc;
> }
>
>
> Is this style still favoured in driver exit paths?
It looks to me like the mutex is not needed in the driver mdio functions as
there's a mutex in the mdiobus functions already.
Am I wrong about that?
Thanks,
John
>From phy/mdio_bus.c
int mdiobus_read(struct mii_bus *bus, int addr, u16 regnum)
{
int retval;
BUG_ON(in_interrupt());
mutex_lock(&bus->mdio_lock);
retval = bus->read(bus, addr, regnum);
mutex_unlock(&bus->mdio_lock);
return retval;
}
EXPORT_SYMBOL(mdiobus_read);
int mdiobus_write(struct mii_bus *bus, int addr, u16 regnum, u16 val)
{
int err;
BUG_ON(in_interrupt());
mutex_lock(&bus->mdio_lock);
err = bus->write(bus, addr, regnum, val);
mutex_unlock(&bus->mdio_lock);
return err;
}
EXPORT_SYMBOL(mdiobus_write);
>
> Thanks,
>
> John
> --
> John Williams, PhD, B.Eng, B.IT
> PetaLogix - Linux Solutions for a Reconfigurable World
> w: www.petalogix.com p: +61-7-30090663 f: +61-7-30090663
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