Re: [PATCH v3 0/7] Remove unneeded build directory traversals

Re: [PATCH v3 0/7] Remove unneeded build directory traversals

[Arnd Bergmann]

On Wed, Mar 15, 2017 at 5:37 PM, Andrew F. Davis <afd@ti.com> wrote:
> Hello all,
>
> I was building a kernel for x86 and noticed Make still descended into
> directories like drivers/gpu/drm/hisilicon, this seems kind of odd given
> nothing will be built here. It looks to be due to some directories being
> included in obj-y unconditionally instead of only when the relevant
> CONFIG_ is set.
>
> These patches are split by subsystem in-case, for some reason, a file in
> a directory does need to be built, I believe I have checked for all
> instances of this, but a quick review from some maintainers would be nice.

I didn't see anything wrong with the patches, and made sure that there
are no tristate symbols controlling the subdirectory for anything that
requires a built-in driver (which would cause a link failure).

I'm not sure about drivers/lguest, which has some special magic
in its Makefile, it's possible that this now fails with CONFIG_LGUEST=m.

      Arnd

Re: [PATCH v3 0/7] Remove unneeded build directory traversals

[Andrew F. Davis]

On 03/15/2017 04:03 PM, Arnd Bergmann wrote:
> On Wed, Mar 15, 2017 at 5:37 PM, Andrew F. Davis <afd@ti.com> wrote:
>> Hello all,
>>
>> I was building a kernel for x86 and noticed Make still descended into
>> directories like drivers/gpu/drm/hisilicon, this seems kind of odd given
>> nothing will be built here. It looks to be due to some directories being
>> included in obj-y unconditionally instead of only when the relevant
>> CONFIG_ is set.
>>
>> These patches are split by subsystem in-case, for some reason, a file in
>> a directory does need to be built, I believe I have checked for all
>> instances of this, but a quick review from some maintainers would be nice.
> 
> I didn't see anything wrong with the patches, and made sure that there
> are no tristate symbols controlling the subdirectory for anything that
> requires a built-in driver (which would cause a link failure).
> 
> I'm not sure about drivers/lguest, which has some special magic
> in its Makefile, it's possible that this now fails with CONFIG_LGUEST=m.
> 

lguest and mmc are the strange ones, so I put them last in the series in
case they did need to be dropped.

lguest was supposed to have been taken from v1:
https://lkml.org/lkml/2016/6/20/1086
but it looks like it didn't so I re-introduced it for v3.

mmc caught some 0-day build warnings but I never got to the bottom of them.

Anyway, I have no problem with these two being held back until the magic
in their Makefile is sorted out.

Thanks,
Andrew

>       Arnd
> 

Re: [PATCH v3 0/7] Remove unneeded build directory traversals

[Arnd Bergmann]

On Wed, Mar 15, 2017 at 10:15 PM, Andrew F. Davis <afd@ti.com> wrote:
> On 03/15/2017 04:03 PM, Arnd Bergmann wrote:
>> On Wed, Mar 15, 2017 at 5:37 PM, Andrew F. Davis <afd@ti.com> wrote:
>>> Hello all,
>>>
>>> I was building a kernel for x86 and noticed Make still descended into
>>> directories like drivers/gpu/drm/hisilicon, this seems kind of odd given
>>> nothing will be built here. It looks to be due to some directories being
>>> included in obj-y unconditionally instead of only when the relevant
>>> CONFIG_ is set.
>>>
>>> These patches are split by subsystem in-case, for some reason, a file in
>>> a directory does need to be built, I believe I have checked for all
>>> instances of this, but a quick review from some maintainers would be nice.
>>
>> I didn't see anything wrong with the patches, and made sure that there
>> are no tristate symbols controlling the subdirectory for anything that
>> requires a built-in driver (which would cause a link failure).
>>
>> I'm not sure about drivers/lguest, which has some special magic
>> in its Makefile, it's possible that this now fails with CONFIG_LGUEST=m.
>>
>
> lguest and mmc are the strange ones, so I put them last in the series in
> case they did need to be dropped.
>
> lguest was supposed to have been taken from v1:
> https://lkml.org/lkml/2016/6/20/1086
> but it looks like it didn't so I re-introduced it for v3.
>
> mmc caught some 0-day build warnings but I never got to the bottom of them.

Ah, I see now what happened to mmc:

obj-$(subst m,y,$(CONFIG_MMC))  += host/
tmio_mmc_core-$(subst m,y,$(CONFIG_MMC_SDHI))   += tmio_mmc_dma.o
obj-$(subst m,y,$(CONFIG_MMC_SDHCI_PCI))        += sdhci-pci-data.o

with CONFIG_MMC=m, this will fail to build the built-in files in
drivers/mmc/host. I suppose this could be expressed in a different
way these days, but dropping the patch would be easier.

     Arnd

Re: [PATCH v3 4/7] macintosh: Only descend into directory when CONFIG_MACINTOSH_DRIVERS is set

[Michael Ellerman]

"Andrew F. Davis" <afd@ti.com> writes:

> When CONFIG_MACINTOSH_DRIVERS is not set make will still descend into the
> macintosh directory but nothing will be built. This produces unneeded
> build artifacts and messages in addition to slowing the build.
> Fix this here.
>
> Signed-off-by: Andrew F. Davis <afd@ti.com>
> ---
>  drivers/Makefile | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

LGTM.

Acked-by: Michael Ellerman <mpe@ellerman.id.au>

cheersj