[Week 3] Import the Xen grant-table bus_dma(9) handlers from OpenBSD

[Pratyush Yadav]

Hi,

I do not have much to report for this week. I was on holiday from 31
May to 2 June.

During the rest of the week, I worked on finishing up my
implementation of the xen-specific bus_dma(9) methods before
submitting them for initial review. I believe it would be complete and
finished up by the time first evaluations roll around, June 11.

I figured out a workaround for a major problem I was facing: in
xen_bus_dmamap_load(), my implementation made it impossible for the
drivers using the method to specify a callback. I fixed/worked around
the problem by using a struct to hold the callback function pointer
and the callback arg of the client, and pass it to bus_dmamap_load().
Take a look at [0] for reference.

I also implemented xen_bus_dmamap_load_mbuf() [3].

Other than this, I fixed a bunch of minor bugs/errors. They are too
small and too many to mention here. Take a look at my GitHub
repository [1] if you are interested.

I maintain a blog on Blogger where I publish my progress every few
days. Check it out if you want more details on what I'm doing [2].

Regards,
Pratyush Yadav


[0] https://github.com/prati0100/freebsd/commit/63598c28b646b8f3537be69e3841a895886f1dfa

[1] https://github.com/prati0100/freebsd/tree/projects/xen_bus_dma

[2] http://pratyushgsoc.blogspot.in/2018/05/import-xen-grant-table-busdma9-handlers.html

[3] https://github.com/prati0100/freebsd/commit/972eb59fa70967b60236ef1899f23024a6a55c17