[PATCH v2 0/9] s390: vfio-ccw code rework

Eric Farman
2019-06-06T20:28:41Z

Now that we've gotten a lot of other series either merged or
pending for the next merge window, I'd like to revisit some
code simplification that I started many moons ago.

In that first series, a couple of fixes got merged into 4.20,
a couple more got some "seems okay" acks/reviews, and the rest
were nearly forgotten about. I dusted them off and did quite a
bit of rework to make things a little more sequential and
providing a better narrative (I think) based on the lessons we
learned in my earlier changes. Because of this rework, the
acks/reviews on the first version didn't really translate to the
code that exists here (patch 1 being the closest exception), so
I didn't apply any of them here. The end result is mostly the
same as before, but now looks like this:

Patch summary:
1: Squash duplicate code
2-4: Remove duplicate code in CCW processor
5-7: Remove one layer of nested arrays
8-9: Combine direct/indirect addressing CCW processors

Using 5.2.0-rc3 as a base plus the vfio-ccw branch of recent fixes,
we shrink the code quite a bit (8.7% according to the bloat-o-meter),
and we remove one set of mallocs/frees on the I/O path by removing
one layer of the nested arrays. There are no functional/behavioral
changes with this series; all the tests that I would run previously
continue to pass/fail as they today.

Changelog:
v1/RFC->v2:
- [Eric] Dropped first two patches, as they have been merged
- [Eric] Shuffling of patches for readability/understandability
- [Halil] Actually added meaningful comments/commit messages
in the patches
v1/RFC: https://patchwork.kernel.org/cover/10675251/

Eric Farman (9):
s390/cio: Squash cp_free() and cp_unpin_free()
s390/cio: Refactor the routine that handles TIC CCWs
s390/cio: Generalize the TIC handler
s390/cio: Use generalized CCW handler in cp_init()
vfio-ccw: Rearrange pfn_array and pfn_array_table arrays
vfio-ccw: Adjust the first IDAW outside of the nested loops
vfio-ccw: Remove pfn_array_table
vfio-ccw: Rearrange IDAL allocation in direct CCW
s390/cio: Combine direct and indirect CCW paths

drivers/s390/cio/vfio_ccw_cp.c | 313 +++++++++++----------------------
1 file changed, 102 insertions(+), 211 deletions(-)

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2.17.1