Re: [PATCH] Fix ext4 bitops

[Geert Uytterhoeven]

On Mon, 4 Feb 2008, Aneesh Kumar K.V wrote:
> On Sun, Feb 03, 2008 at 01:39:02PM +0100, Geert Uytterhoeven wrote:
> > On Sun, 3 Feb 2008, Heiko Carstens wrote:
> > > On Fri, Feb 01, 2008 at 10:04:04PM +0100, Bastian Blank wrote:
> > > > On Fri, Feb 01, 2008 at 12:22:57PM -0800, Andrew Morton wrote:
> > > > > On Fri, 1 Feb 2008 21:02:08 +0100
> > > > > Bastian Blank <bastian@xxxxxxxxxxxx> wrote:
> > > > > > Fix ext4 bitops.
> > > > > 
> > > > > This is incomplete.  Please tell us what was "fixed".
> > > > > 
> > > > > If it was a build error then please quote the compile error output in the
> > > > > changelog, as well as the usual description of what the problem is, and how
> > > > > it was fixed.
> > > > 
> > > > | fs/ext4/mballoc.c: In function 'ext4_mb_generate_buddy':
> > > > | fs/ext4/mballoc.c:954: error: implicit declaration of function 'generic_find_next_le_bit'
> > > > 
> > > > The s390 specific bitops uses parts of the generic implementation.
> > > > Include the correct header.
> > > 
> > > That doesn't work:
> > > 
> > > fs/built-in.o: In function `ext4_mb_release_inode_pa':
> > > mballoc.c:(.text+0x95a8a): undefined reference to `generic_find_next_le_bit'
> > > fs/built-in.o: In function `ext4_mb_init_cache':
> > > mballoc.c:(.text+0x967ea): undefined reference to `generic_find_next_le_bit'
> > > 
> > > This still needs generic_find_next_le_bit which comes
> > > from lib/find_next_bit.c. That one doesn't get built on s390 since we
> > > don't set GENERIC_FIND_NEXT_BIT.
> > > Currently we have the lengthly patch below queued.
> > 
> > Similar issue on m68k. As Bastian also saw it on powerpc, I'm getting the
> > impression the ext4 people don't (compile) test on big endian machines?
> 
> I have sent this patches to linux-arch expecting a review from
> different arch people. It is true that the patches are tested only on
> powerpc, x86-64, x86. That's the primary reason of me sending the
> patches to linux-arch.
> 
> http://marc.info/?l=linux-arch&m=119503501127737&w=2

Sometimes it's difficult to see what can go wrong due to a single patch that
just adds a #define. Sorry, I missed the lack of prototype for
generic_find_next_le_bit() and that we don't set GENERIC_FIND_NEXT_BIT,
just like s390.

And yes, usually I rely on the -mm autocompiler to catch things like
this, but this time it didn't work out...

Gr{oetje,eeting}s,

						Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
							    -- Linus Torvalds
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