tree 77d710a9f2706d48f98e30c3e66eca6048a1fd0f
parent 2d5e33f8b77a27522bda58b570dae0c8f9d64ca0
author Dan Williams <dan.j.williams@intel.com> 1426282040 -0400
committer Dan Williams <dan.j.williams@intel.com> 1426528273 -0400

block: base support for pfn i/o

Allow block device drivers to opt-in to receiving bio(s) where the
bio_vec(s) point to memory that is not backed by struct page entries.
When a driver opts in it asserts that it will use the pfn version of the
dma mapping routines and does not use pfn_to_page() in its submission
path.

TODO: add kmap_pfn() and kmap_atomic_pfn() for drivers that want to
touch bio_vec buffers with the cpu prior to submission to a
low-level-device-driver.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>