RE: [PATCH v4 1/1] i40e: validate ring_len parameter against hardware-specific values

[Romanowski, Rafal]

> -----Original Message-----
> From: Intel-wired-lan <intel-wired-lan-bounces@xxxxxxxxxx> On Behalf Of
> Loktionov, Aleksandr
> Sent: Monday, November 17, 2025 12:59
> To: gregory.herrero@xxxxxxxxxx; Nguyen, Anthony L
> <anthony.l.nguyen@xxxxxxxxx>; Kitszel, Przemyslaw
> <przemyslaw.kitszel@xxxxxxxxx>; andrew+netdev@xxxxxxx;
> davem@xxxxxxxxxxxxx; edumazet@xxxxxxxxxx; kuba@xxxxxxxxxx;
> pabeni@xxxxxxxxxx
> Cc: intel-wired-lan@xxxxxxxxxxxxxxxx; netdev@xxxxxxxxxxxxxxx; linux-
> kernel@xxxxxxxxxxxxxxx
> Subject: Re: [Intel-wired-lan] [PATCH v4 1/1] i40e: validate ring_len parameter
> against hardware-specific values
> 
> 
> 
> > -----Original Message-----
> > From: gregory.herrero@xxxxxxxxxx <gregory.herrero@xxxxxxxxxx>
> > Sent: Monday, November 17, 2025 9:33 AM
> > To: Loktionov, Aleksandr <aleksandr.loktionov@xxxxxxxxx>; Nguyen,
> > Anthony L <anthony.l.nguyen@xxxxxxxxx>; Kitszel, Przemyslaw
> > <przemyslaw.kitszel@xxxxxxxxx>; andrew+netdev@xxxxxxx;
> > davem@xxxxxxxxxxxxx; edumazet@xxxxxxxxxx; kuba@xxxxxxxxxx;
> > pabeni@xxxxxxxxxx
> > Cc: intel-wired-lan@xxxxxxxxxxxxxxxx; netdev@xxxxxxxxxxxxxxx; linux-
> > kernel@xxxxxxxxxxxxxxx; Gregory Herrero <gregory.herrero@xxxxxxxxxx>
> > Subject: [PATCH v4 1/1] i40e: validate ring_len parameter against
> > hardware-specific values
> >
> > From: Gregory Herrero <gregory.herrero@xxxxxxxxxx>
> >
> > The maximum number of descriptors supported by the hardware is
> > hardware dependent and can be retrieved using
> First paragraph uses “hardware dependent” (no hyphen) while later text uses
> “hardware‑specific” (hyphenated).
> Prefer “hardware‑dependent” for consistency.
> 
> > i40e_get_max_num_descriptors().
> > Move this function to a shared header and use it when checking for
> > valid ring_len parameter rather than using hardcoded value.
> >
> > By fixing an over-acceptance issue, behavior change could be seen
> > where ring_len could now be rejected while configuring rx and tx
> > queues if its size is larger than the hardware-specific maximum number
> > of descriptors.
> >
> The message explains the behavioral change but does not state how the change
> was tested (e.g., which MAC types exercised, ethtool -G paths, VF configuration
> via virtchnl, acceptance/rejection boundaries).
> Netdev routinely asks for this when behavior changes.
> 
> > Fixes: 55d225670def ("i40e: add validation for ring_len param")
> > Signed-off-by: Gregory Herrero <gregory.herrero@xxxxxxxxxx>
> > ---
> >  drivers/net/ethernet/intel/i40e/i40e.h         | 18
> > ++++++++++++++++++
> >  drivers/net/ethernet/intel/i40e/i40e_ethtool.c | 12 ------------
> > .../net/ethernet/intel/i40e/i40e_virtchnl_pf.c |  4 ++--
> >  3 files changed, 20 insertions(+), 14 deletions(-)
> >
> > diff --git a/drivers/net/ethernet/intel/i40e/i40e.h
> > b/drivers/net/ethernet/intel/i40e/i40e.h
> > index 801a57a925da..5b367397ae43 100644
> > --- a/drivers/net/ethernet/intel/i40e/i40e.h
> > +++ b/drivers/net/ethernet/intel/i40e/i40e.h
> > @@ -1418,4 +1418,22 @@ static inline struct i40e_veb
> > *i40e_pf_get_main_veb(struct i40e_pf *pf)
> >  	return (pf->lan_veb != I40E_NO_VEB) ? pf->veb[pf->lan_veb] :
> > NULL;  }
> 
> ...
> 
> > --
> > 2.51.0


Tested-by: Rafal Romanowski <rafal.romanowski@xxxxxxxxx>