[openib-general] [kDAPL]How to register a vmalloc() allocated buffer

[Ian Jiang]

Hi James,
You are always so kind!
Now I have a question about reading a buffer of a application in user space.
Is it the only way to use the uDAPL?
I used to have an idea like this:
The application in user space gives the virtual start address and length of
its data buffer to a kernel module program. This kernel program acts as a
application of the kDAPL and registers the user space data buffer with the
kDAPl, then request a RDMA read operation to complete the data transferring.
But I think it is not feasible after getting your last reply. Am I right?
Please give some suggestion and thanks very much!

On 12/6/05, James Lentini <jlentini at netapp.com> wrote:
>
> Hi Ian,
>
> An IB HCA needs to be able to DMA the memory used for RDMA read. Since
> vmalloc does not guarantee that the memory it returns can be accessed
> via DMA, you should not use vmalloc.
>
> james
>



--
Ian Jiang
ianjiang.ict at gmail.com

Laboratory of Spatial Information Technology
Division of System Architecture
Institute of Computing Technology
Chinese Academy of Sciences
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