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 <[email protected]> Signed-off-by: Jens Axboe <[email protected]>
kawasaki · Apr 2, 2021 · f8b78ca · f8b78ca
1 parent de3510e
commit f8b78ca
Showing 1 changed file with 4 additions and 0 deletions.
diff --git 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;