[PATCH] block: don't ignore REQ_NOWAIT for direct IO

From: Pavel Begunkov
Date: Fri Nov 20 2020 - 12:13:46 EST


io_uring's direct nowait requests end up waiting on io_schedule() in
sbitmap, that's seems to be so because blkdev_direct_IO() fails to
propagate IOCB_NOWAIT to a bio and hence to blk-mq.

Signed-off-by: Pavel Begunkov <asml.silence@xxxxxxxxx>
---
fs/block_dev.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/fs/block_dev.c b/fs/block_dev.c
index 9e84b1928b94..e7e860c78d93 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -263,6 +263,8 @@ __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);

@@ -416,6 +418,8 @@ __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, int nr_pages)
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;
--
2.24.0