[PATCH 5/5] aio: add support for file based polled IO

[Jens Axboe <axboe@kernel.dk>]

Needs further work, but this should work fine on normal setups
with a file system on a pollable block device.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
 fs/aio.c       | 2 ++
 fs/direct-io.c | 4 +++-
 fs/iomap.c     | 7 +++++--
 3 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/fs/aio.c b/fs/aio.c
index 500da3ffc376..e02085fe10d7 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -1310,6 +1310,8 @@ static struct block_device *aio_bdev_host(struct kiocb *req)
 
 	if (S_ISBLK(inode->i_mode))
 		return I_BDEV(inode);
+	else if (inode->i_sb && inode->i_sb->s_bdev)
+		return inode->i_sb->s_bdev;
 
 	return NULL;
 }
diff --git a/fs/direct-io.c b/fs/direct-io.c
index a5a4e5a1423e..34de494e9061 100644
--- a/fs/direct-io.c
+++ b/fs/direct-io.c
@@ -477,8 +477,10 @@ static inline void dio_bio_submit(struct dio *dio, struct dio_submit *sdio)
 	if (sdio->submit_io) {
 		sdio->submit_io(bio, dio->inode, sdio->logical_offset_in_bio);
 		dio->bio_cookie = BLK_QC_T_NONE;
-	} else
+	} else {
 		dio->bio_cookie = submit_bio(bio);
+		WRITE_ONCE(dio->iocb->ki_blk_qc, dio->bio_cookie);
+	}
 
 	sdio->bio = NULL;
 	sdio->boundary = 0;
diff --git a/fs/iomap.c b/fs/iomap.c
index 74c1f37f0fd6..4cf412b6230a 100644
--- a/fs/iomap.c
+++ b/fs/iomap.c
@@ -1555,6 +1555,7 @@ iomap_dio_zero(struct iomap_dio *dio, struct iomap *iomap, loff_t pos,
 	struct page *page = ZERO_PAGE(0);
 	int flags = REQ_SYNC | REQ_IDLE;
 	struct bio *bio;
+	blk_qc_t qc;
 
 	bio = bio_alloc(GFP_KERNEL, 1);
 	bio_set_dev(bio, iomap->bdev);
@@ -1570,7 +1571,9 @@ iomap_dio_zero(struct iomap_dio *dio, struct iomap *iomap, loff_t pos,
 	bio_set_op_attrs(bio, REQ_OP_WRITE, flags);
 
 	atomic_inc(&dio->ref);
-	return submit_bio(bio);
+	qc = submit_bio(bio);
+	WRITE_ONCE(dio->iocb->ki_blk_qc, qc);
+	return qc;
 }
 
 static loff_t
@@ -1680,7 +1683,7 @@ iomap_dio_bio_actor(struct inode *inode, loff_t pos, loff_t length,
 		atomic_inc(&dio->ref);
 
 		dio->submit.last_queue = bdev_get_queue(iomap->bdev);
-		dio->submit.cookie = submit_bio(bio);
+		dio->iocb->ki_blk_qc = dio->submit.cookie = submit_bio(bio);
 	} while (nr_pages);
 
 	if (need_zeroout) {
-- 
2.17.1