Re: [PATCH 1/1] net: phylib: remove the length limitation of miibus id

[Florian Fainelli]

Hi,

Le 03/20/12 11:53, Dong Aisheng a Ãcrit :
> On Tue, Mar 20, 2012 at 1:32 AM, Shawn Guo<shawn.guo@xxxxxxxxxx>  wrote:
> > On 20 March 2012 12:23, Dong Aisheng<b29396@xxxxxxxxxxxxx>  wrote:
> > > From: Dong Aisheng<dong.aisheng@xxxxxxxxxx>
> > >
> > > When convert to dt, the length of old mii bus id (17 bytes) is not
> > > sufficent to use.
> > > For example, the bus id could be 800f0000.ethernet-1:00 in DT.
> > >
> > > This patch removes the bus id length limitation by changing the
> > > bus id to a const char pionter and user could dynamically set the
> > > bus id via kasprintf function call.
> > >
> > > Since then no users use MII_BUS_ID_SIZE any more, just remove it.
> > >
> > > Signed-off-by: Dong Aisheng<dong.aisheng@xxxxxxxxxx>
> > > ---
> > > The simplest way may just change MII_BUS_ID_SIZE to a more bigger size,
> > > but i'm not sure that's gonna be accepted.
> >
> > The simplest fix has been applied on -next tree as below.
> Oh, i missed it, seems my patch covers that change.
> But that patch only fixed wrong phy_name buffer length issue.
> My patch is totally remove the length limitation of bus id and phy_name
> or the bus id name will be truncated if it's longer than MII_BUS_ID_SIZE
> which is not a comfortable limitation.

Then just increase the bus id size locally for your driver. Drivers that 
can live with a static allocation are better of using it.

Your patch completely missed testing the return value of kasprintf(), 
and its return value can be NULL, please fix this at least.

> > commit a7ed07d51c8abdb407be454c6cb6cfad613759d9
> > Author: Richard Zhao<richard.zhao@xxxxxxxxxx>
> > Date:   Sun Jan 29 22:08:12 2012 +0000
> >
> >     net: fec: correct phy_name buffer length when init phy_name
> >
> >     Fix the bug that we got wrong phy_name on imx6q sabrelite board.
> >     snprintf used wrong length of phy_name.
> >     phy_name length is MII_BUS_ID_SIZE + 3 rather not MII_BUS_ID_SIZE.
> >     I change it to sizeof(phy_name).
> >
> >     Signed-off-by: Richard Zhao<richard.zhao@xxxxxxxxxx>
> >     Acked-by: Shawn Guo<shawn.guo@xxxxxxxxxx>
> >     Acked-by: Florian Fainelli<florian@xxxxxxxxxxx>
> >     Signed-off-by: David S. Miller<davem@xxxxxxxxxxxxx>
> >
> > diff --git a/drivers/net/ethernet/freescale/fec.c
> > b/drivers/net/ethernet/freescale/fec.c
> > index 7b25e9c..1c7aad8 100644
> > --- a/drivers/net/ethernet/freescale/fec.c
> > +++ b/drivers/net/ethernet/freescale/fec.c
> > @@ -990,7 +990,7 @@ static int fec_enet_mii_probe(struct net_device *ndev)
> >                 phy_id = 0;
> >         }
> >
> > -       snprintf(phy_name, MII_BUS_ID_SIZE, PHY_ID_FMT, mdio_bus_id, phy_id);
> > +       snprintf(phy_name, sizeof(phy_name), PHY_ID_FMT, mdio_bus_id, phy_id);
> >         phy_dev = phy_connect(ndev, phy_name,&fec_enet_adjust_link, 0,
> >                               fep->phy_interface);
> >         if (IS_ERR(phy_dev)) {
> --
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