From: Keith Busch <kbusch@xxxxxxxxxx>
Some users of the dmapool need their allocations to happen in ascending
order. The recent optimizations pushed the blocks in reverse order, so
restore the previous behavior by linking the next available block from
low-to-high.
Fixes: ced6d06a81fb69 ("dmapool: link blocks across pages")
Reported-by: Bryan O'Donoghue <bryan.odonoghue@xxxxxxxxxx>
Signed-off-by: Keith Busch <kbusch@xxxxxxxxxx>