block: don't ignore REQ_NOWAIT for direct IO

If IOCB_NOWAIT is set on submission, then that needs to get propagated to
REQ_NOWAIT on the block side. Otherwise we completely lose this
information, and any issuer of IOCB_NOWAIT IO will potentially end up
blocking on eg request allocation on the storage side.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/fs/block_dev.c b/fs/block_dev.c
index 28d583f..09d6f72 100644 (file)
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -275,6 +275,8 @@ __blkdev_direct_IO_simple(struct kiocb *iocb, struct iov_iter *iter,
                bio.bi_opf = dio_bio_write_op(iocb);
                task_io_account_write(ret);
        }
+       if (iocb->ki_flags & IOCB_NOWAIT)
+               bio.bi_opf |= REQ_NOWAIT;
        if (iocb->ki_flags & IOCB_HIPRI)
                bio_set_polled(&bio, iocb);
 
@@ -428,6 +430,8 @@ static ssize_t __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
                        bio->bi_opf = dio_bio_write_op(iocb);
                        task_io_account_write(bio->bi_iter.bi_size);
                }
+               if (iocb->ki_flags & IOCB_NOWAIT)
+                       bio->bi_opf |= REQ_NOWAIT;
 
                dio->size += bio->bi_iter.bi_size;
                pos += bio->bi_iter.bi_size;