Mapping memory between kernel and user space

[Rajat Sharma]

Hi Sri,

LKD chapter 15 is right resource for you. specifically you can look
for remap_pfn_range function to map I/O memory to user space.

Thanks,
Rajat

On Fri, Feb 11, 2011 at 6:12 PM, YOUNGWHAN SONG <breadncup at gmail.com> wrote:
> Hi Sri,
>
>
> On Feb 10, 2011, at 11:56 AM, Sri Ram Vemulpali wrote:
>
>> Hi Santosa,
>>
>>   Can you please be more explicit. I do manage buffers internally in
>> my module.
>> Some cases if it full I will lose data. Can you please provide more
>> detailed explanation
>> on how to approach this. Thanks.
>>
>> --Sri
>>
>> On Wed, Feb 9, 2011 at 10:21 PM, Mulyadi Santosa
>> <mulyadi.santosa at gmail.com> wrote:
>>> On Thu, Feb 10, 2011 at 06:45, Sri Ram Vemulpali
>>> <sri.ram.gmu06 at gmail.com> wrote:
>>>> Hi all,
>>>>
>>>>  How do I map some space between kernel and user space. Can anyone
>>>> point me in to right direction. I was trying to map the packets from
>>>> my netfilter function to kernel user space, to avoid over head of
>>>> copying. Thanks in advance.
>
> Isn't it possible if your driver supports mmap? Have you checked it out in Linux Kernel Drive chapter 15?
>
>
>>>
>>> Not trying to discourage you, but I assume your "filtering" function
>>> will be engaged many many times in the case of rapid traffic...thus,
>>> the buffer might grow rapidly too, right? In that case, are you sure
>>> direct mapping could cope with it? Well unless you're ready to loose
>>> some data .....
>>>
>>> Anyway, I think you can do that by reserve the buffer in user space
>>> and the get_user_page() them. As the bridge, a unique device with
>>> ioctl() might do the job.
>>>
>>> --
>>> regards,
>>>
>>> Mulyadi Santosa
>>> Freelance Linux trainer and consultant
>>>
>>> blog: the-hydra.blogspot.com
>>> training: mulyaditraining.blogspot.com
>>>
>>
>>
>>
>> --
>> Regards,
>> Sri.
>>
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>
> Daniel.
>
>
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