Re: raid5: coding style cleanup / refactor

On Tue, 12 Jun 2007 10:41:03 -0700
Dan Williams [off-list ref] wrote:

Most of the raid5 code predates git so the coding style violations have
been present for a long time.  However, now that major new patches are
arriving, checkpatch.pl complains about these old violations.  Instead of
attempting to justify the warnings as "this is what raid5 used to do", this
patch brings the code in line with the current style.

Note that this is more than a simple reformatting.  The majority of the
80-column violations were in the handle_stripe5 and handle_stripe6
routines.  By introducing the 'stripe_head_state' and 'r6_state' objects
large portions of the logic could be moved to sub-routines, reclaiming a
column's worth of indentation.

'stripe_head_state' consumes all of the automatic variables that previously
stood alone in handle_stripe.  'r6_state' contains the handle_stripe6
specific variables like p_failed and q_failed.  

One of the nice side effects of the 'stripe_head_state' change is that it
allows for further reductions in code duplication between raid5 and raid6
(note: unfortunately the other 80-column violations hide the code
duplication-removal effect in the diffstat).  The following new routines
are shared between raid5 and raid6:

	handle_completed_write_requests
	handle_requests_to_failed_array
	handle_stripe_expansion

Trivia:
* PRINTK and RAID5_DEBUG is replaced with pr_debug
* struct field comments moved to the top (kernel-doc format)

Unfortunately these cleanups get into a huge fight with your very own
git-md-accel.patch:

patching file drivers/md/raid5.c
Hunk #1 succeeded at 58 (offset 1 line).
Hunk #2 succeeded at 78 (offset 1 line).
Hunk #3 succeeded at 91 (offset 1 line).
Hunk #4 FAILED at 127.
Hunk #5 succeeded at 157 (offset 2 lines).
Hunk #6 succeeded at 167 (offset 2 lines).
Hunk #7 succeeded at 211 (offset 2 lines).
Hunk #8 succeeded at 224 (offset 2 lines).
Hunk #9 succeeded at 235 with fuzz 1 (offset 3 lines).
Hunk #10 succeeded at 263 (offset 3 lines).
Hunk #11 succeeded at 304 (offset 3 lines).
Hunk #12 succeeded at 943 (offset 578 lines).
Hunk #13 succeeded at 995 (offset 578 lines).
Hunk #14 succeeded at 1015 (offset 578 lines).
Hunk #15 succeeded at 1124 (offset 578 lines).
Hunk #16 succeeded at 1136 (offset 578 lines).
Hunk #17 succeeded at 1155 (offset 578 lines).
Hunk #18 succeeded at 1206 (offset 578 lines).
Hunk #19 succeeded at 1251 (offset 578 lines).
Hunk #20 succeeded at 1269 (offset 578 lines).
Hunk #21 succeeded at 1278 (offset 578 lines).
Hunk #22 FAILED at 1524.
Hunk #23 FAILED at 1555.
Hunk #24 succeeded at 1541 (offset 547 lines).
Hunk #25 succeeded at 1989 with fuzz 2 (offset 978 lines).
Hunk #26 FAILED at 2009.
Hunk #27 FAILED at 2056.
Hunk #28 FAILED at 2064.
Hunk #29 FAILED at 2084.
Hunk #30 FAILED at 2094.
Hunk #31 FAILED at 2135.
Hunk #32 FAILED at 2182.
Hunk #33 FAILED at 2193.
Hunk #34 FAILED at 2215.
Hunk #35 FAILED at 2225.
Hunk #36 FAILED at 2242.
Hunk #37 FAILED at 2278.
Hunk #38 succeeded at 3381 with fuzz 1 (offset 2026 lines).
Hunk #39 FAILED at 4002.
Hunk #40 FAILED at 4016.
Hunk #41 FAILED at 4054.
Hunk #42 FAILED at 4216.
Hunk #43 FAILED at 4235.
Hunk #44 FAILED at 4253.
Hunk #45 FAILED at 4282.
Hunk #46 FAILED at 4309.
Hunk #47 FAILED at 4330.
Hunk #48 FAILED at 4358.
Hunk #49 FAILED at 4400.
Hunk #50 FAILED at 4419.
Hunk #51 FAILED at 4427.
Hunk #52 FAILED at 4482.
Hunk #53 FAILED at 4501.
Hunk #54 FAILED at 4534.
Hunk #55 FAILED at 4564.
Hunk #56 FAILED at 4619.
Hunk #57 FAILED at 4663.
Hunk #58 succeeded at 3377 (offset 648 lines).
Hunk #59 succeeded at 3415 (offset 648 lines).
Hunk #60 succeeded at 3503 (offset 648 lines).
Hunk #61 succeeded at 3538 (offset 648 lines).
Hunk #62 succeeded at 3580 (offset 648 lines).
Hunk #63 succeeded at 3617 (offset 648 lines).
Hunk #64 succeeded at 3814 (offset 648 lines).
Hunk #65 succeeded at 3865 (offset 648 lines).
Hunk #66 succeeded at 3918 (offset 648 lines).
Hunk #67 succeeded at 3972 (offset 650 lines).
Hunk #68 succeeded at 4032 (offset 650 lines).
Hunk #69 succeeded at 4123 (offset 650 lines).
Hunk #70 succeeded at 4157 (offset 650 lines).
Hunk #71 succeeded at 4197 (offset 650 lines).
Hunk #72 succeeded at 4228 (offset 650 lines).
Hunk #73 succeeded at 4340 (offset 650 lines).
Hunk #74 succeeded at 4375 (offset 650 lines).
Hunk #75 succeeded at 4514 (offset 650 lines).
Hunk #76 succeeded at 4549 (offset 650 lines).
Hunk #77 succeeded at 4633 (offset 650 lines).
Hunk #78 succeeded at 4652 (offset 650 lines).
Hunk #79 succeeded at 4670 (offset 650 lines).
Hunk #80 succeeded at 4699 (offset 650 lines).
34 out of 80 hunks FAILED -- saving rejects to file drivers/md/raid5.c.rej
patching file include/linux/raid/raid5.h
Hunk #2 FAILED at 118.
Hunk #3 FAILED at 192.
Hunk #4 succeeded at 302 (offset 57 lines).
Hunk #5 succeeded at 335 (offset 57 lines).
Hunk #6 succeeded at 370 (offset 57 lines).
2 out of 6 hunks FAILED -- saving rejects to file include/linux/raid/raid5.h.rej

I assume that you're prepared to repair all that damage to your tree, but
it seems a bit masochistic?