Pull MD changes from Song:
"Summary:
1. Fix race condition in md_ioctl(), by Dae R. Jeong;
2. Initialize read_slot properly for raid10, by Kevin Vigor;
3. Code cleanup, by Pankaj Gupta;
4. md-cluster resync/reshape fix, by Zhao Heming."
* 'md-next' of https://git.kernel.org/pub/scm/linux/kernel/git/song/md:
md/cluster: fix deadlock when node is doing resync job
md/cluster: block reshape with remote resync job
md: use current request time as base for ktime comparisons
md: add comments in md_flush_request()
md: improve variable names in md_flush_request()
md/raid10: initialize r10_bio->read_slot before use.
md: fix a warning caused by a race between concurrent md_ioctl()s