md/raid1: count resync requests in nr_pending.

Both normal IO and resync IO can be retried with reschedule_retry()
and so be counted into ->nr_queued, but only normal IO gets counted in
->nr_pending.

Before the recent improvement to RAID1 resync there could only
possibly have been one or the other on the queue.  When handling a
read failure it could only be normal IO.  So when handle_read_error()
called freeze_array() the fact that freeze_array only compares
->nr_queued against ->nr_pending was safe.

But now that these two types can interleave, we can have both normal
and resync IO requests queued, so we need to count them both in
nr_pending.

Reported-by: Brassow Jonathan <jbrassow@redhat.com>
Signed-off-by: NeilBrown <neilb@suse.de>
md: Make sync_page_io aware of underlying block size.

sync_page_io is sometimes called on to read an object smaller than a
page.  If that happens to be smaller than the physical block size
of the device, the size needs to be rounded up.

This is particularly import for use of sync_page_io by dm-raid.

This is a simple fix for a bug that stops dm-raid from working on 4K
phys-sector devices.  So it seems suitable for -stable at low
priority.

Signed-off-by: NeilBrown  <neilb@suse.de>
Cc: stable@vger.kernel.org (After release of 3.18)
Reported-by: Liuhua Wang <lwang@suse.com>
md/bitmap: remove bev_logical_block_size rounding where not needed.

Now that sync_page_io rounds up the size, read_sb_page() doesn't
need too.

Signed-off-by: NeilBrown <neilb@suse.de>