null_blk: restart request processing on completion handler
authorAkinobu Mita <akinobu.mita@gmail.com>
Mon, 1 Jun 2015 23:35:10 +0000 (08:35 +0900)
committerJens Axboe <axboe@fb.com>
Tue, 2 Jun 2015 02:09:05 +0000 (20:09 -0600)
commit8b70f45e2eb275da886b9c9dee190436d12d876a
treeae6830a996f4e54980dc8c8bcdf4a2a058e9b38e
parent419c21a3b6275d40a10901f700efcd40515b6db6
null_blk: restart request processing on completion handler

When irqmode=2 (IRQ completion handler is timer) and queue_mode=1
(Block interface to use is rq), the completion handler should restart
request handling for any pending requests on a queue because request
processing stops when the number of commands are queued more than
hw_queue_depth (null_rq_prep_fn returns BLKPREP_DEFER).

Without this change, the following command cannot finish.

# modprobe null_blk irqmode=2 queue_mode=1 hw_queue_depth=1
# fio --name=t --rw=read --size=1g --direct=1 \
  --ioengine=libaio --iodepth=64 --filename=/dev/nullb0

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Jens Axboe <axboe@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
drivers/block/null_blk.c