Re: [PATCH] bcm47xx: fix build regression

Paul E. McKenney
2017-06-01T22:16:41Z

On Wed, May 31, 2017 at 09:30:19PM +0200, Arend van Spriel wrote:
> On 31-05-17 18:31, Paul E. McKenney wrote:
> > On Wed, May 31, 2017 at 03:34:57PM +0200, Arnd Bergmann wrote:
> >> On Wed, May 31, 2017 at 3:12 PM, Paul E. McKenney
> >> <paulmck@linux.vnet.ibm.com> wrote:
> >>> On Wed, May 31, 2017 at 12:21:10PM +0200, Arnd Bergmann wrote:
> >>>> On Wed, May 31, 2017 at 11:43 AM, Arend van Spriel
> >>>> <arend.vanspriel@broadcom.com> wrote:
> >>>>> On 5/30/2017 1:20 PM, Arnd Bergmann wrote:
> >>>>>>
> >>>>>> An unknown change in the kernel headers caused a build regression
> >>>>>> in an MTD partition driver:
> >>>>>>
> >>>>>> In file included from drivers/mtd/bcm47xxpart.c:12:0:
> >>>>>> include/linux/bcm47xx_nvram.h: In function 'bcm47xx_nvram_init_from_mem':
> >>>>>> include/linux/bcm47xx_nvram.h:27:10: error: 'ENOTSUPP' undeclared (first
> >>>>>> use in this function)
> >>>>>>
> >>>>>> Clearly we want to include linux/errno.h here.
> >>>>>
> >>>>>
> >>>>> unfortunate that you did not find the commit that caused this build
> >>>>> regression. You could produce preprocessor output when it was working to see
> >>>>> where errno.h got implicitly included and start looking there for git
> >>>>> history.
> >>>>
> >>>> I did a 'git bisect run make drivers/mtd/bcm47xxpart.o' now, which pointed to
> >>>> 0bc2d534708b ("rcu: Refactor #includes from include/linux/rcupdate.h").
> >>>>
> >>>> That commit seems reasonable, it was just bad luck that it caused this
> >>>> regression. The commit is currently in the rcu/rcu/next branch of tip.git,
> >>>> so Paul could merge the patch there.
>
> Arnd,
>
> Thanks for digging a bit further. I am a sucker for telling the whole story.
>
> >>>
> >>> Apologies for the inconvenience, not sure why 0day test robot didn't
> >>> find this. Probably because it cannot test each and every driver. ;-)
> >>
> >> No worries.
> >>
> >>> This patch, correct?
> >>>
> >>> https://lkml.org/lkml/2017/5/30/348
> >>
> >> Right, I should have included the link.
> >
> > And my turn to say "no worries". ;-)
> >
> > I reworked the commit log to tell the full story as shown below.
> > Anything I misstated or otherwise missed?
>
> Maybe add the 'Fixes:' tag, ie.:
>
> Fixes: 0bc2d534708b ("rcu: Refactor #includes from
> include/linux/rcupdate.h")
>
> Seems a bit redundant given that you mentioned it in the commit message,
> but it might be looked for in kernel-stats scripts.

Had to rebase anyway for other reasons, so why not?

Thanx, Paul

> Regards,
> Arend
>
> > Thanx, Paul
> >
> > ------------------------------------------------------------------------
> >
> > commit ff278071dce9af9da2b5e2b33f682710a855d266
> > Author: Arnd Bergmann <arnd@arndb.de>
> > Date: Wed May 31 09:26:07 2017 -0700
> >
> > bcm47xx: fix build regression
> >
> > Commit 0bc2d534708b ("rcu: Refactor #includes from include/linux/rcupdate.h")
> > caused a build regression in an MTD partition driver:
> >
> > In file included from drivers/mtd/bcm47xxpart.c:12:0:
> > include/linux/bcm47xx_nvram.h: In function 'bcm47xx_nvram_init_from_mem':
> > include/linux/bcm47xx_nvram.h:27:10: error: 'ENOTSUPP' undeclared (first use in this function)
> >
> > The rcupdate.h file has no particular need for linux/errno.h, so this
> > commit includes linux/errno.h into bcm47xx_nvram.h.
> >
> > Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> > Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
> >
> > diff --git a/include/linux/bcm47xx_nvram.h b/include/linux/bcm47xx_nvram.h
> > index 2793652fbf66..a414a2b53e41 100644
> > --- a/include/linux/bcm47xx_nvram.h
> > +++ b/include/linux/bcm47xx_nvram.h
> > @@ -8,6 +8,7 @@
> > #ifndef __BCM47XX_NVRAM_H
> > #define __BCM47XX_NVRAM_H
> >
> > +#include <linux/errno.h>
> > #include <linux/types.h>
> > #include <linux/kernel.h>
> > #include <linux/vmalloc.h>
> >
>