Subject: Re: [PATCH net-next 3/3] iavf: remove mask from iavf_irq_enable_queues()

From: Maciej Fijalkowski <[email-masked]>
Date: Tue, 6 Jun 2023 12:26:45 +0200

On Mon, Jun 05, 2023 at 01:56:48PM -0600, Ahmed Zaki wrote:
> 
> On 2023-06-05 13:25, Maciej Fijalkowski wrote:
> > On Fri, Jun 02, 2023 at 10:13:02AM -0700, Tony Nguyen wrote:
> > > From: Ahmed Zaki <[email-masked]>
> > > 
> > > Enable more than 32 IRQs by removing the u32 bit mask in
> > > iavf_irq_enable_queues(). There is no need for the mask as there are no
> > > callers that select individual IRQs through the bitmask. Also, if the PF
> > > allocates more than 32 IRQs, this mask will prevent us from using all of
> > > them.
> > > 
> > > The comment in iavf_register.h is modified to show that the maximum
> > > number allowed for the IRQ index is 63 as per the iAVF standard 1.0 [1].
> > please use imperative mood:
> > "modify the comment in..."
> > 
> > besides, it sounds to me like a bug, we were not following the spec, no?
> 
> yes, but all PF's were allocating  <= 16 IRQs, so it was not causing any
> issues.
> 
> 
> > 
> > > link: [1] https://www.intel.com/content/dam/www/public/us/en/documents/product-specifications/ethernet-adaptive-virtual-function-hardware-spec.pdf
> > > Signed-off-by: Ahmed Zaki <[email-masked]>
> > > Tested-by: Rafal Romanowski <[email-masked]>
> > > Signed-off-by: Tony Nguyen <[email-masked]>
> > Reviewed-by: Maciej Fijalkowski <[email-masked]>
> > 
> > > ---
> > >   drivers/net/ethernet/intel/iavf/iavf.h          |  2 +-
> > >   drivers/net/ethernet/intel/iavf/iavf_main.c     | 15 ++++++---------
> > >   drivers/net/ethernet/intel/iavf/iavf_register.h |  2 +-
> > >   3 files changed, 8 insertions(+), 11 deletions(-)
> > > 
> > > diff --git a/drivers/net/ethernet/intel/iavf/iavf.h b/drivers/net/ethernet/intel/iavf/iavf.h
> > > index 9abaff1f2aff..39d0fe76a38f 100644
> > > --- a/drivers/net/ethernet/intel/iavf/iavf.h
> > > +++ b/drivers/net/ethernet/intel/iavf/iavf.h
> > > @@ -525,7 +525,7 @@ void iavf_set_ethtool_ops(struct net_device *netdev);
> > >   void iavf_update_stats(struct iavf_adapter *adapter);
> > >   void iavf_reset_interrupt_capability(struct iavf_adapter *adapter);
> > >   int iavf_init_interrupt_scheme(struct iavf_adapter *adapter);
> > > -void iavf_irq_enable_queues(struct iavf_adapter *adapter, u32 mask);
> > > +void iavf_irq_enable_queues(struct iavf_adapter *adapter);
> > >   void iavf_free_all_tx_resources(struct iavf_adapter *adapter);
> > >   void iavf_free_all_rx_resources(struct iavf_adapter *adapter);
> > > diff --git a/drivers/net/ethernet/intel/iavf/iavf_main.c b/drivers/net/ethernet/intel/iavf/iavf_main.c
> > > index 3a78f86ba4f9..1332633f0ca5 100644
> > > --- a/drivers/net/ethernet/intel/iavf/iavf_main.c
> > > +++ b/drivers/net/ethernet/intel/iavf/iavf_main.c
> > > @@ -359,21 +359,18 @@ static void iavf_irq_disable(struct iavf_adapter *adapter)
> > >   }
> > >   /**
> > > - * iavf_irq_enable_queues - Enable interrupt for specified queues
> > > + * iavf_irq_enable_queues - Enable interrupt for all queues
> > >    * @adapter: board private structure
> > > - * @mask: bitmap of queues to enable
> > >    **/
> > > -void iavf_irq_enable_queues(struct iavf_adapter *adapter, u32 mask)
> > > +void iavf_irq_enable_queues(struct iavf_adapter *adapter)
> > >   {
> > >   	struct iavf_hw *hw = &adapter->hw;
> > >   	int i;
> > >   	for (i = 1; i < adapter->num_msix_vectors; i++) {
> > > -		if (mask & BIT(i - 1)) {
> > > -			wr32(hw, IAVF_VFINT_DYN_CTLN1(i - 1),
> > > -			     IAVF_VFINT_DYN_CTLN1_INTENA_MASK |
> > > -			     IAVF_VFINT_DYN_CTLN1_ITR_INDX_MASK);
> > > -		}
> > > +		wr32(hw, IAVF_VFINT_DYN_CTLN1(i - 1),
> > > +		     IAVF_VFINT_DYN_CTLN1_INTENA_MASK |
> > > +		     IAVF_VFINT_DYN_CTLN1_ITR_INDX_MASK);
> > >   	}
> > >   }
> > > @@ -387,7 +384,7 @@ void iavf_irq_enable(struct iavf_adapter *adapter, bool flush)
> > >   	struct iavf_hw *hw = &adapter->hw;
> > >   	iavf_misc_irq_enable(adapter);
> > > -	iavf_irq_enable_queues(adapter, ~0);
> > > +	iavf_irq_enable_queues(adapter);
> > >   	if (flush)
> > >   		iavf_flush(hw);
> > > diff --git a/drivers/net/ethernet/intel/iavf/iavf_register.h b/drivers/net/ethernet/intel/iavf/iavf_register.h
> > > index bf793332fc9d..a19e88898a0b 100644
> > > --- a/drivers/net/ethernet/intel/iavf/iavf_register.h
> > > +++ b/drivers/net/ethernet/intel/iavf/iavf_register.h
> > > @@ -40,7 +40,7 @@
> > >   #define IAVF_VFINT_DYN_CTL01_INTENA_MASK IAVF_MASK(0x1, IAVF_VFINT_DYN_CTL01_INTENA_SHIFT)
> > >   #define IAVF_VFINT_DYN_CTL01_ITR_INDX_SHIFT 3
> > >   #define IAVF_VFINT_DYN_CTL01_ITR_INDX_MASK IAVF_MASK(0x3, IAVF_VFINT_DYN_CTL01_ITR_INDX_SHIFT)
> > > -#define IAVF_VFINT_DYN_CTLN1(_INTVF) (0x00003800 + ((_INTVF) * 4)) /* _i=0...15 */ /* Reset: VFR */
> > so this was wrong even before as not indicating 31 as max?
> 
> Correct, but again no issues.
> 
> Given that, should I re-send to net ?

probably with older kernels PFs would still be allocating <= 16 irqs,
right? not sure if one could take a PF and hack it to request for more
than 32 irqs and then hit the wall with the mask you're removing.