Hi Randy,
On Thu, Oct 13, 2011 at 4:00 AM, Randy Dunlap <rdunlap at xenotime.net> wrote:
> On 10/11/2011 02:23 AM, Sumit Semwal wrote:
>> Add documentation for dma buffer sharing framework, explaining the
>> various operations, members and API of the dma buffer sharing
>> framework.
>>
>> Signed-off-by: Sumit Semwal <sumit.semwal at linaro.org>
>> Signed-off-by: Sumit Semwal <sumit.semwal at ti.com>
>> ---
>> ?Documentation/dma-buf-sharing.txt | ?210
>> +++++++++++++++++++++++++++++++++++++
<snip>
>> + ? ?if the new buffer-user has stricter 'backing-storage constraints', and
>> the
>> + ? ?exporter can handle these constraints, the exporter can just stall on
>> the
>> + ? ?get_scatterlist till all outstanding access is completed (as signalled
>> by
>
> ? ? ? ? ? ? ? ? ? ? ? until
>
Thanks for your review; I will update all these in the next version.
>> + ? ?put_scatterlist).
>> + ? ?Once all ongoing access is completed, the exporter could potentially
>> move
>> + ? ?the buffer to the stricter backing-storage, and then allow further
>> + ? ?{get,put}_scatterlist operations from any buffer-user from the migrated
>> + ? ?backing-storage.
>> +
>> + ? If the exporter cannot fulfill the backing-storage constraints of the new
>> + ? buffer-user device as requested, dma_buf_attach() would return an error
>> to
>> + ? denote non-compatibility of the new buffer-sharing request with the
>> current
>> + ? buffer.
>> +
>> + ? If the exporter chooses not to allow an attach() operation once a
>> + ? get_scatterlist has been called, it simply returns an error.
>> +
>> +- mmap file operation
>> + ? An mmap() file operation is provided for the fd associated with the
>> buffer.
>> + ? If the exporter defines an mmap operation, the mmap() fop calls this to
>> allow
>> + ? mmap for devices that might need it; if not, it returns an error.
>> +
>> +References:
>> +[1] struct dma_buf_ops in include/linux/dma-buf.h
>> +[2] All interfaces mentioned above defined in include/linux/dma-buf.h
>
>
> --
> ~Randy
> *** Remember to use Documentation/SubmitChecklist when testing your code ***
>
Best regards,
~Sumit.
