Linux next-20170407 failed to build on ARM due to usage of mod in btrfs code

[Adam Borowski]

On Sat, Apr 08, 2017 at 02:45:34PM -0300, Fabio Estevam wrote:
> On Sat, Apr 8, 2017 at 1:02 PM, Icenowy Zheng <icenowy at aosc.io> wrote:
> > Hello everyone,
> > Today I tried to build a kernel with btrfs enabled on ARM, then when linking
> > I met such an error:
> >
> > ```
> > fs/built-in.o: In function `scrub_bio_end_io_worker':
> > acl.c:(.text+0x2f0450): undefined reference to `__aeabi_uldivmod'
> > fs/built-in.o: In function `scrub_extent_for_parity':
> > acl.c:(.text+0x2f0bcc): undefined reference to `__aeabi_uldivmod'
> > fs/built-in.o: In function `scrub_raid56_parity':
> > acl.c:(.text+0x2f12a8): undefined reference to `__aeabi_uldivmod'
> > acl.c:(.text+0x2f15c4): undefined reference to `__aeabi_uldivmod'
> > ```
> >
> > These functions are found at fs/btrfs/scrub.c .
> >
> > After disabling btrfs the kernel is successfully built.
> 
> I see the same error with ARM imx_v6_v7_defconfig + btrfs support.
> 
> Looks like it is caused by commit 7d0ef8b4dbbd220 ("Btrfs: update
> scrub_parity to use u64 stripe_len").

+1, my bisect just finished, same bad commit.

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