Re: linux-next: build warning after merge of the rdma tree

[Nathan Chancellor <nathan@kernel.org>]

On Wed, Feb 10, 2021 at 09:47:42AM -0400, Jason Gunthorpe wrote:
> On Wed, Feb 10, 2021 at 09:11:49PM +1100, Stephen Rothwell wrote:
> > Hi all,
> > 
> > After merging the rdma tree, today's linux-next build (htmldocs) produced
> > this warning:
> > 
> > drivers/infiniband/core/device.c:859: warning: Function parameter or member 'dev' not described in 'ib_port_immutable_read'
> > drivers/infiniband/core/device.c:859: warning: Function parameter or member 'port' not described in 'ib_port_immutable_read'
> > 
> > Introduced by commit
> > 
> >   7416790e2245 ("RDMA/core: Introduce and use API to read port immutable data")
> 
> drivers/infinband is W=1 clean right now in linux-next
> 
> But how can I build *only* drivers/infiniband using W=1 so I can keep
> it that way?
> 
> The rest of the kernel is not clean and creates too much warning noise
> to be usable, even with my mini config.
> 
> Just doing a 'make W=1 drivers/infiniband' is sort of OK, but then I
> end up compiling things twice
> 
> Does anyone know a good solution?
> 
> Jason
> 

Hi Jason,

There was at one point an effort from Andrew Lunn to allow subsystems to
opt in W=1 unconditionally but Masahiro had some concerns with both
approaches:

https://lore.kernel.org/r/20200919190258.3673246-1-andrew@lunn.ch/
https://lore.kernel.org/r/20201001011232.4050282-1-andrew@lunn.ch/

It looks like btrfs has just opted to copy the W=1 flags into its
Makefile:

https://git.kernel.org/next/linux-next/c/3a7b58d632b24ec3321f1ee3027bd407e09e515e

Cheers,
Nathan