Re: [PATCH net-next] Add support for netvsc build without CONFIG_SYSFS flag

[Greg KH <greg@kroah.com>]

On Thu, May 08, 2014 at 03:13:19PM +0000, Haiyang Zhang wrote:
> 
> 
> > -----Original Message-----
> > From: Greg KH [mailto:greg@kroah.com]
> > Sent: Thursday, May 8, 2014 5:13 AM
> > To: Haiyang Zhang
> > Cc: davem@davemloft.net; netdev@vger.kernel.org; olaf@aepfle.de;
> > jasowang@redhat.com; driverdev-devel@linuxdriverproject.org; linux-
> > kernel@vger.kernel.org
> > Subject: Re: [PATCH net-next] Add support for netvsc build without
> > CONFIG_SYSFS flag
> > 
> > On Wed, May 07, 2014 at 03:45:04PM -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@microsoft.com>
> > > Reviewed-by: K. Y. Srinivasan <kys@microsoft.com>
> > > ---
> > >  drivers/net/hyperv/hyperv_net.h   |    2 ++
> > >  drivers/net/hyperv/netvsc_drv.c   |   12 +++++++++++-
> > >  drivers/net/hyperv/rndis_filter.c |    4 ++--
> > >  3 files changed, 15 insertions(+), 3 deletions(-)
> > >
> > > diff --git a/drivers/net/hyperv/hyperv_net.h
> > > b/drivers/net/hyperv/hyperv_net.h index 4b7df5a..23b96bc 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;
> > >
> > > diff --git a/drivers/net/hyperv/netvsc_drv.c
> > > b/drivers/net/hyperv/netvsc_drv.c index 939e3af..07896f3 100644
> > > --- a/drivers/net/hyperv/netvsc_drv.c
> > > +++ b/drivers/net/hyperv/netvsc_drv.c
> > > @@ -52,6 +52,8 @@ static int ring_size = 128;  module_param(ring_size,
> > > int, S_IRUGO);  MODULE_PARM_DESC(ring_size, "Ring buffer size (# of
> > > pages)");
> > >
> > > +unsigned int netvsc_num_queue = 1;
> > > +
> > >  static void do_set_multicast(struct work_struct *w)  {
> > >  	struct net_device_context *ndevctx = @@ -639,9 +641,11 @@ int
> > > netvsc_recv_callback(struct hv_device *device_obj,
> > >  		__vlan_hwaccel_put_tag(skb, htons(ETH_P_8021Q),
> > >  				       packet->vlan_tci);
> > >
> > > +#ifdef CONFIG_SYSFS
> > >  	skb_record_rx_queue(skb, packet->channel->
> > >  			    offermsg.offer.sub_channel_index %
> > >  			    net->real_num_rx_queues);
> > > +#endif
> > 
> > Why is this a sysfs-only function?  It should have nothing to do with sysfs, right?
> > So why would the driver care?
> 
> Without CONFIG_SYSFS the multi-receive queues are not allocated, see below, and 
> the variable real_num_rx_queues is not defined, so we skip this function.
> 
> In alloc_netdev_mqs(), file "net/core/dev.c":
> #ifdef CONFIG_SYSFS
>         dev->num_rx_queues = rxqs;
>         dev->real_num_rx_queues = rxqs;
>         if (netif_alloc_rx_queues(dev))
>                 goto free_all;
> #endif

Then you need to structure your driver better :)

greg k-h