RE: [PATCH net-next, v2] Add support for netvsc build without CONFIG_SYSFS flag

[Haiyang Zhang]

> -----Original Message-----
> From: Greg KH [mailto:greg@xxxxxxxxx]
> Sent: Thursday, May 8, 2014 4:04 PM
> To: Haiyang Zhang
> Cc: davem@xxxxxxxxxxxxx; netdev@xxxxxxxxxxxxxxx; olaf@xxxxxxxxx;
> jasowang@xxxxxxxxxx; driverdev-devel@xxxxxxxxxxxxxxxxxxxxxx; linux-
> kernel@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH net-next, v2] Add support for netvsc build without
> CONFIG_SYSFS flag
> 
> On Thu, May 08, 2014 at 01:41:33PM -0700, Haiyang Zhang wrote:
> > This change ensures the driver can be built successfully without the
> > CONFIG_SYSFS flag.
> > MS-TFS: 182270
> >
> > Signed-off-by: Haiyang Zhang <haiyangz@xxxxxxxxxxxxx>
> > Reviewed-by: K. Y. Srinivasan <kys@xxxxxxxxxxxxx>
> > ---
> >  drivers/net/hyperv/hyperv_net.h   |   28 ++++++++++++++++++++++++++++
> >  drivers/net/hyperv/netvsc_drv.c   |   13 +++++++------
> >  drivers/net/hyperv/rndis_filter.c |    4 ++--
> >  3 files changed, 37 insertions(+), 8 deletions(-)
> >
> > diff --git a/drivers/net/hyperv/hyperv_net.h
> > b/drivers/net/hyperv/hyperv_net.h index 4b7df5a..02358cb 100644
> > --- a/drivers/net/hyperv/hyperv_net.h
> > +++ b/drivers/net/hyperv/hyperv_net.h
> > @@ -87,6 +87,8 @@ struct ndis_recv_scale_cap { /*
> > NDIS_RECEIVE_SCALE_CAPABILITIES */  #define HASH_KEYLEN
> > NDIS_RSS_HASH_SECRET_KEY_MAX_SIZE_REVISION_2
> >  extern u8 netvsc_hash_key[];
> >
> > +extern unsigned int netvsc_num_queue;
> > +
> >  struct ndis_recv_scale_param { /* NDIS_RECEIVE_SCALE_PARAMETERS */
> >  	struct ndis_obj_header hdr;
> >
> > @@ -178,6 +180,32 @@ struct rndis_device {
> >  	unsigned char hw_mac_adr[ETH_ALEN];
> >  };
> >
> > +static inline void netvsc_record_rx_queue(struct sk_buff *skb,
> > +					  struct hv_netvsc_packet *packet,
> > +					  struct net_device *ndev)
> > +{
> > +#ifdef CONFIG_SYSFS
> > +	skb_record_rx_queue(skb, packet->channel->
> > +			    offermsg.offer.sub_channel_index %
> > +			    ndev->real_num_rx_queues);
> > +#endif
> 
> Really?  Do all other wireless drivers have this type of #ifdef needed?
> 
> > +}
> > +
> > +static inline void netvsc_show_num_queue(struct device *dev,
> > +					 struct net_device *ndev)
> > +{
> > +#ifdef CONFIG_SYSFS
> > +	dev_info(dev, "real num tx,rx queues:%u, %u\n",
> > +		 ndev->real_num_tx_queues, ndev->real_num_rx_queues);
> #endif
> 
> Do network drivers really spam the kernel log with this type of thing?
> If you have sysfs, why is this needed in the kernel log?
> 
> > +}
> > +
> > +static inline void netvsc_set_num_queue(unsigned int *nq) { #ifdef
> > +CONFIG_SYSFS
> > +	*nq = num_online_cpus();
> > +#endif
> > +}
> 
> I really feel that something is odd here...

I looked around the other drivers, and the netif_set_real_num_rx_queues() 
function. It's already switched to no-op without CONFIG_SYSFS flag. So I will 
rely on this, and don't have to handle the flag in my code. 

Also, the dev_info can be removed.

Thanks,
- Haiyang

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