zloop: clear nowait flag in workqueue context

zloop: clear nowait flag in workqueue context

The zloop driver advertises REQ_NOWAIT support through BLK_FEAT_NOWAIT
(enabled by default for all blk-mq devices), and honors the nowait
behavior throughout zloop_queue_rq().

However, actual I/O to the backing file is performed in a workqueue,
where blocking is allowed.

To avoid imposing unnecessary non-blocking constraints in this blocking
context, clear the REQ_NOWAIT flag before processing the request in the
workqueue context.

Signed-off-by: Chaitanya Kulkarni <ckulkarnilinux@gmail.com>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>