Re: [uClinux-dev] [PATCH] NOMMU: use copy_*_user_page() in access_process_vm()

[Jie Zhang <jie.zhang@analog.com>]

On 11/25/2009 02:16 PM, Jamie Lokier wrote:
> Mike Frysinger wrote:
>> From: Jie Zhang<jie.zhang@analog.com>
>>
>> The mmu code uses the copy_*_user_page() variants in access_process_vm()
>> rather than copy_*_user() as the former includes an icache flush.  This is
>> important when doing things like setting software breakpoints with gdb.
>> So switch the nommu code over to do the same.
>
> Reasonable, but it's a bit subtle don't you think?
> How about a one-line comment saying why it's using copy_*_user_page()?
>
> (If it was called copy_*_user_flush_icache() I wouldn't say anything,
> but it isn't).
>
But I think it's well known in Linux kernel developers that 
copy_to_user_page and copy_from_user_page should do cache flushing. It's 
documented in Documentation/cachetlb.txt. I don't think it's necessary 
to replicate it here.


Jie