md/raid5: separate out the easy conditions in need_this_block.
authorNeilBrown <neilb@suse.de>
Mon, 2 Feb 2015 00:37:59 +0000 (11:37 +1100)
committerNeilBrown <neilb@suse.de>
Tue, 3 Feb 2015 21:35:51 +0000 (08:35 +1100)
Some of the conditions in need_this_block have very straight
forward motivation.  Separate those out and document them.

Signed-off-by: NeilBrown <neilb@suse.de>
drivers/md/raid5.c

Simple merge