Subject: Re: [PATCH net-next 5/5] net: dsa: mv88e6xxx: implementation of dynamic ATU entries

From: Simon Horman <[email-masked]>
Date: Fri, 3 Feb 2023 09:20:22 +0100

On Thu, Feb 02, 2023 at 06:00:00PM +0100, [email-masked] wrote:
> On 2023-01-31 19:56, Simon Horman wrote:
> > > --- a/drivers/net/dsa/mv88e6xxx/chip.c
> > > +++ b/drivers/net/dsa/mv88e6xxx/chip.c
> > > @@ -42,6 +42,7 @@
> > >  #include "ptp.h"
> > >  #include "serdes.h"
> > >  #include "smi.h"
> > > +#include "switchdev.h"
> > > 
> > >  static void assert_reg_lock(struct mv88e6xxx_chip *chip)
> > >  {
> > > @@ -2726,18 +2727,25 @@ static int mv88e6xxx_port_fdb_add(struct
> > > dsa_switch *ds, int port,
> > >  				  const unsigned char *addr, u16 vid,
> > >  				  u16 fdb_flags, struct dsa_db db)
> > >  {
> > > +	bool is_dynamic = !!(fdb_flags & DSA_FDB_FLAG_DYNAMIC);
> > >  	struct mv88e6xxx_chip *chip = ds->priv;
> > > +	u8 state;
> > >  	int err;
> > > 
> > > -	/* Ignore entries with flags set */
> > > -	if (fdb_flags)
> > > -		return 0;
> > > +	state = MV88E6XXX_G1_ATU_DATA_STATE_UC_STATIC;
> > > +	if (is_dynamic)
> > > +		state = MV88E6XXX_G1_ATU_DATA_STATE_UC_AGE_7_NEWEST;
> > 
> > What if flags other than DSA_FDB_FLAG_DYNAMIC are set (in future)?
> 
> They will have to be caught and handled here if there is support for it,
> e.g. something like...
> 
> else if (someflag)
>         dosomething();
> 
> For now only one flag will actually be set and they are mutually exclusive,
> as they will not make sense together with the potential flags I know, but
> that can change at some time of course.

Yes, I see that is workable. I do feel that checking for other flags would
be a bit more robust. But as you say, there are none. So whichever
approach you prefer is fine by me.

> > > +	else
> > > +		if (fdb_flags)
> > nit: else if (fdb_flags)
> > > +			return 0;
> > ...