On 14-03-26 04:41 AM, Geert Uytterhoeven wrote:
> On Thu, Feb 13, 2014 at 10:15 PM, Paul Gortmaker
> <paul.gortmaker@xxxxxxxxxxxxx> wrote:
>> While copy_to/from_user_page() users are uncommon, there is one in
>> drivers/staging/lustre/lustre/libcfs/linux/linux-curproc.c which leads
>> to the following:
>>
>> ERROR: "sparc32_cachetlb_ops" [drivers/staging/lustre/lustre/libcfs/libcfs.ko] undefined!
>>
>> during routine allmodconfig build coverage. The reason this happens
>> is as follows:
>>
>> In arch/sparc/include/asm/cacheflush_32.h we have:
>>
>> #define flush_cache_page(vma,addr,pfn) \
>> sparc32_cachetlb_ops->cache_page(vma, addr)
>>
>> #define copy_to_user_page(vma, page, vaddr, dst, src, len) \
>> do { \
>> flush_cache_page(vma, vaddr, page_to_pfn(page));\
>> memcpy(dst, src, len); \
>> } while (0)
>> #define copy_from_user_page(vma, page, vaddr, dst, src, len) \
>> do { \
>> flush_cache_page(vma, vaddr, page_to_pfn(page));\
>> memcpy(dst, src, len); \
>> } while (0)
>>
>> However, sparc32_cachetlb_ops isn't exported and hence the error.
>>
>> Signed-off-by: Paul Gortmaker <paul.gortmaker@xxxxxxxxxxxxx>
>
> Sorry for only noticing now. A similar fix for pa-risc was reverted:
>
> "Christoph Hellwig <hch@xxxxxxxxxxxxx> commented:
> This one shouldn't go in - Geert sent it a bit prematurely, as Lustre
> shouldn't use it just to reimplement core VM functionality (which it
> shouldn't use either, but that's a separate story)."
Generally speaking I agree, and every time I touch lustre, I feel
like I need to go home and have a shower. However, in this case,
lustre wasn't actually directly calling flush_cache_page type core
VM ops directly, and I couldn't convince myself of an argument
of why a modular driver should be forbidden from using either
of copy_to/from_user_page()...
Either way is fine with me. If a revert is desired and we want
to make lustre depend on CONFIG_BROKEN (okay, a bit harsh) or
don't allow lustre to be modular, that is also fine.
Paul.
--
>
> http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=a446e72bc15c7bfd2c953e56064ace3566c79b0e
>
> 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
>
--
To unsubscribe from this list: send the line "unsubscribe sparclinux" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
