[RFC] intel-post-reloc branch.

[Thomas H. <th...@tu...>]

Hi.

I've pushed the intel-post-reloc branch with the following stuff:

1) Full backwards compatibility.
2) A new reloc type 1, which is applied _after_ all validations and with 
slightly different format.
3) If the buffer is idle, type 1 relocations are performed using the new 
kmap_atomic_prot_pfn if it's available.
4) If the buffer is busy, It's never mapped, and relocations are 
performed using a single dword 2D blit, and we never have to idle the 
buffer. This comes at a cost of an additional single MI_FLUSH after all 
blit-relocations have been performed.

This could help avoid pre-validation relocation processing, race 
conditions due to the relocatee not being on the unfenced list when 
relocs are applied and unnecessary buffer idling.

/Thomas