Command allocation is the thing that takes the longest in the main i/o
path, so check for controller lockup immediately after this to prevent
submitting commands to locked up controller as much as possible.
Reviewed-by: NScott Teel <scott.teel@pmcs.com>
Signed-off-by: NDon Brace <don.brace@pmcs.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>