[PULL REQUEST] minor md updates for 2.6.34

[PULL REQUEST] minor md updates for 2.6.34

[Neil Brown]

Hi Linus,

Yes, I know I missed the boat, and I won't lose any sleep if this
doesn't get accepted, but here are a few minor improvements that I
would rather were in than not.

I have another bugfix coming (relating to merge_bvec_fn handling) but
I'm not confident I have that right yet so it'll some later as a
separate 'bugfix'.

Thanks,
NeilBrown


The following changes since commit 25cf84cf377c0aae5dbcf937ea89bc7893db5176:
  Linus Torvalds (1):
        Merge git://git.kernel.org/.../amit/virtio-console

are available in the git repository at:

  git://neil.brown.name/md/ for-linus

H Hartley Sweeten (1):
      drivers/md: Remove unnecessary casts of void *

NeilBrown (1):
      md: remove some dead fields from mddev_s

Paul Clements (1):
      md: expose max value of behind writes counter

 drivers/md/bitmap.c    |   37 ++++++++++++++++++++++++++++++++-----
 drivers/md/bitmap.h    |    1 +
 drivers/md/faulty.c    |    6 +++---
 drivers/md/md.h        |    3 ---
 drivers/md/multipath.c |    2 +-
 drivers/md/raid1.c     |    8 ++++----
 drivers/md/raid10.c    |    8 ++++----
 drivers/md/raid5.c     |   10 +++++-----
 8 files changed, 50 insertions(+), 25 deletions(-)

tip: origin tree build failure (x86, 32-bit, allyesconfig)

[Ingo Molnar]

* Neil Brown <neilb@suse.de> wrote:

> are available in the git repository at:
> 
>   git://neil.brown.name/md/ for-linus

( Note, i'm re-using this old MD pull request thread to report a bug in a pull 
  request you sent to Linus in the past two days. I havent found the pull 
  request nor the patch on lkml. )

All 32-bit x86 builds (x86, allyesconfig) that enable RAID are failing with 
this build failure:

 drivers/built-in.o: In function `raid5_compute_sector':
 raid5.c:(.text+0x2e42ac): undefined reference to `__umoddi3'
 raid5.c:(.text+0x2e42d8): undefined reference to `__umoddi3'
 raid5.c:(.text+0x2e42ff): undefined reference to `__umoddi3'
 raid5.c:(.text+0x2e4327): undefined reference to `__umoddi3'
 raid5.c:(.text+0x2e4385): undefined reference to `__umoddi3'
 drivers/built-in.o:raid5.c:(.text+0x2e43bc): more undefined references to `__umoddi3' follow

Caused by this commit:

  35f2a59: md/raid5: allow for more than 2^31 chunks.

I've reverted the commit from -tip for now.

Thanks,

	Ingo

Re: tip: origin tree build failure (x86, 32-bit, allyesconfig)

[Linus Torvalds]

On Thu, 22 Apr 2010, Ingo Molnar wrote:
> 
> All 32-bit x86 builds (x86, allyesconfig) that enable RAID are failing with 
> this build failure:
> 
>  drivers/built-in.o: In function `raid5_compute_sector':
>  raid5.c:(.text+0x2e42ac): undefined reference to `__umoddi3'
>  raid5.c:(.text+0x2e42d8): undefined reference to `__umoddi3'
>  raid5.c:(.text+0x2e42ff): undefined reference to `__umoddi3'
>  raid5.c:(.text+0x2e4327): undefined reference to `__umoddi3'
>  raid5.c:(.text+0x2e4385): undefined reference to `__umoddi3'
>  drivers/built-in.o:raid5.c:(.text+0x2e43bc): more undefined references to `__umoddi3' follow
> 
> Caused by this commit:
> 
>   35f2a59: md/raid5: allow for more than 2^31 chunks.

Gaah, yes.

How about just making it "unsigned long" instead of sector_t, and telling 
people that if they have more than 2**32 chunks in their RAID array, they 
should damn well use a 64-bit CPU.

The alternative, of course, is to use "sector_div()" everywhere. Neil?

		Linus

Re: tip: origin tree build failure (x86, 32-bit, allyesconfig)

[Neil Brown]

On Thu, 22 Apr 2010 11:12:41 -0700 (PDT)
Linus Torvalds <torvalds@linux-foundation.org> wrote:

> 
> 
> On Thu, 22 Apr 2010, Ingo Molnar wrote:
> > 
> > All 32-bit x86 builds (x86, allyesconfig) that enable RAID are failing with 
> > this build failure:
> > 
> >  drivers/built-in.o: In function `raid5_compute_sector':
> >  raid5.c:(.text+0x2e42ac): undefined reference to `__umoddi3'
> >  raid5.c:(.text+0x2e42d8): undefined reference to `__umoddi3'
> >  raid5.c:(.text+0x2e42ff): undefined reference to `__umoddi3'
> >  raid5.c:(.text+0x2e4327): undefined reference to `__umoddi3'
> >  raid5.c:(.text+0x2e4385): undefined reference to `__umoddi3'
> >  drivers/built-in.o:raid5.c:(.text+0x2e43bc): more undefined references to `__umoddi3' follow
> > 
> > Caused by this commit:
> > 
> >   35f2a59: md/raid5: allow for more than 2^31 chunks.
> 
> Gaah, yes.
> 
> How about just making it "unsigned long" instead of sector_t, and telling 
> people that if they have more than 2**32 chunks in their RAID array, they 
> should damn well use a 64-bit CPU.
> 
> The alternative, of course, is to use "sector_div()" everywhere. Neil?

Sorry, using sector_div everywhere is definitely the right thing to do.
Please pull one more patch from

  git://neil.brown.name/md/ for-linus

Thanks,
NeilBrown