Pull MD updates and fixes from Song:
"1. Various raid5 fix and clean up, by Logan Gunthorpe and David Sloan.
2. Raid10 performance optimization, by Yu Kuai."
* 'md-next' of https://git.kernel.org/pub/scm/linux/kernel/git/song/md:
md: Fix spelling mistake in comments of r5l_log
md/raid5: Wait for MD_SB_CHANGE_PENDING in raid5d
md/raid10: convert resync_lock to use seqlock
md/raid10: fix improper BUG_ON() in raise_barrier()
md/raid10: prevent unnecessary calls to wake_up() in fast path
md/raid10: don't modify 'nr_waitng' in wait_barrier() for the case nowait
md/raid10: factor out code from wait_barrier() to stop_waiting_barrier()
md: Remove extra mddev_get() in md_seq_start()
md/raid5: Remove unnecessary bio_put() in raid5_read_one_chunk()
md/raid5: Ensure stripe_fill happens on non-read IO with journal
md/raid5: Don't read ->active_stripes if it's not needed
md/raid5: Cleanup prototype of raid5_get_active_stripe()
md/raid5: Drop extern on function declarations in raid5.h
md/raid5: Refactor raid5_get_active_stripe()
md: Replace snprintf with scnprintf
md/raid10: fix compile warning
md/raid5: Fix spelling mistakes in comments