Em Quarta 15 Fevereiro 2006 12:53, Rodrigo Rosenfeld Rosas escreveu:
>Em Terça 14 Fevereiro 2006 22:30, Jan Kiszka escreveu:
>>...
>>
>>>> You cannot mmap before you know precisely for which user this should
>>>> take place.
>>>
>>> Do you mean that if I use the 'current' and current->mm struct of the
>>> driver, when mmaping, the user won't be able to use the returned pointer?
>>
>>To mmap you need to know the target process, more precisely its mm. This
>>is typically derived from the invocation context of the service call
>>("current" is a pointer to the current process). But init_module runs in
>>the context of modprobe. Even worse, the process later opening and
>>mapping some buffer may not even exist at that time!
>
>Right, I've already verified this on practice... I'm mmaping on open handler
>for now just for testing the mmap, but I'll change it to the ioctl mmap
>handler.
>
>It seems to work. I mapped high_memory and could read and modify it from
> user space. The memory values mantained betweens the many open calls. I
> read, printed the values and increment them by one. On next time, the value
> shown was incremented... All seems perfect but I still didn't test with
> real acquire code... When I do so, I'll let you know.
>
>I still need to test the vmaops. I think I'll test them tomorrow. I need to
>begin writing an article that my advisor asked me to. I need to finish it
>until march, 10.
Ok, I tested the vmaops too and it also worked as expected. I think you could
merge rtdm_mmap and related stuff to mainline RTDM. Thank you for your
precious work. Unfortunately you'll need to wait a while until I test them on
the real video driver. I had to stop working on it for writing the article.
When I finish the article I'll test them on real hardware but I see no
reasons for not working...
Best Regards,
Rodrigo.
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