block: add a bio_submit_or_kill helper

block: add a bio_submit_or_kill helper

Factor the common logic for the ioctl helpers to either submit a bio or
end if the process is being killed.  As this is now the only user of
bio_await_chain, open code that.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Link: https://patch.msgid.link/20260407140538.633364-5-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>