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From: Jens Axboe <axboe@kernel.dk>
To: io-uring@vger.kernel.org, linux-xfs@vger.kernel.org
Cc: hch@lst.de, andres@anarazel.de, david@fromorbit.com,
	djwong@kernel.org, Jens Axboe <axboe@kernel.dk>
Subject: [PATCH 1/9] iomap: cleanup up iomap_dio_bio_end_io()
Date: Fri, 21 Jul 2023 10:16:42 -0600	[thread overview]
Message-ID: <20230721161650.319414-2-axboe@kernel.dk> (raw)
In-Reply-To: <20230721161650.319414-1-axboe@kernel.dk>

Make the logic a bit easier to follow:

1) Add a release_bio out path, as everybody needs to touch that, and
   have our bio ref check jump there if it's non-zero.
2) Add a kiocb local variable.
3) Add comments for each of the three conditions (sync, inline, or
   async workqueue punt).

No functional changes in this patch.

Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
 fs/iomap/direct-io.c | 46 +++++++++++++++++++++++++++++---------------
 1 file changed, 31 insertions(+), 15 deletions(-)

diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c
index ea3b868c8355..0ce60e80c901 100644
--- a/fs/iomap/direct-io.c
+++ b/fs/iomap/direct-io.c
@@ -152,27 +152,43 @@ void iomap_dio_bio_end_io(struct bio *bio)
 {
 	struct iomap_dio *dio = bio->bi_private;
 	bool should_dirty = (dio->flags & IOMAP_DIO_DIRTY);
+	struct kiocb *iocb = dio->iocb;
 
 	if (bio->bi_status)
 		iomap_dio_set_error(dio, blk_status_to_errno(bio->bi_status));
+	if (!atomic_dec_and_test(&dio->ref))
+		goto release_bio;
 
-	if (atomic_dec_and_test(&dio->ref)) {
-		if (dio->wait_for_completion) {
-			struct task_struct *waiter = dio->submit.waiter;
-			WRITE_ONCE(dio->submit.waiter, NULL);
-			blk_wake_io_task(waiter);
-		} else if (dio->flags & IOMAP_DIO_WRITE) {
-			struct inode *inode = file_inode(dio->iocb->ki_filp);
-
-			WRITE_ONCE(dio->iocb->private, NULL);
-			INIT_WORK(&dio->aio.work, iomap_dio_complete_work);
-			queue_work(inode->i_sb->s_dio_done_wq, &dio->aio.work);
-		} else {
-			WRITE_ONCE(dio->iocb->private, NULL);
-			iomap_dio_complete_work(&dio->aio.work);
-		}
+	/*
+	 * Synchronous dio, task itself will handle any completion work
+	 * that needs after IO. All we need to do is wake the task.
+	 */
+	if (dio->wait_for_completion) {
+		struct task_struct *waiter = dio->submit.waiter;
+
+		WRITE_ONCE(dio->submit.waiter, NULL);
+		blk_wake_io_task(waiter);
+		goto release_bio;
+	}
+
+	/* Read completion can always complete inline. */
+	if (!(dio->flags & IOMAP_DIO_WRITE)) {
+		WRITE_ONCE(iocb->private, NULL);
+		iomap_dio_complete_work(&dio->aio.work);
+		goto release_bio;
 	}
 
+	/*
+	 * Async DIO completion that requires filesystem level completion work
+	 * gets punted to a work queue to complete as the operation may require
+	 * more IO to be issued to finalise filesystem metadata changes or
+	 * guarantee data integrity.
+	 */
+	WRITE_ONCE(iocb->private, NULL);
+	INIT_WORK(&dio->aio.work, iomap_dio_complete_work);
+	queue_work(file_inode(iocb->ki_filp)->i_sb->s_dio_done_wq,
+			&dio->aio.work);
+release_bio:
 	if (should_dirty) {
 		bio_check_pages_dirty(bio);
 	} else {
-- 
2.40.1


  reply	other threads:[~2023-07-21 16:18 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-07-21 16:16 [PATCHSET v5 0/9] Improve async iomap DIO performance Jens Axboe
2023-07-21 16:16 ` Jens Axboe [this message]
2023-07-21 16:16 ` [PATCH 2/9] iomap: add IOMAP_DIO_INLINE_COMP Jens Axboe
2023-07-21 16:16 ` [PATCH 3/9] iomap: treat a write through cache the same as FUA Jens Axboe
2023-07-21 16:25   ` Darrick J. Wong
2023-07-21 16:27     ` Jens Axboe
2023-07-21 16:47       ` Darrick J. Wong
2023-07-21 16:52         ` Jens Axboe
2023-07-21 16:16 ` [PATCH 4/9] iomap: completed polled IO inline Jens Axboe
2023-07-21 16:16 ` [PATCH 5/9] iomap: only set iocb->private for polled bio Jens Axboe
2023-07-21 16:16 ` [PATCH 6/9] fs: add IOCB flags related to passing back dio completions Jens Axboe
2023-07-21 16:28   ` Darrick J. Wong
2023-07-21 16:30     ` Jens Axboe
2023-07-21 16:43       ` Jens Axboe
2023-07-21 16:16 ` [PATCH 7/9] io_uring/rw: add write support for IOCB_DIO_CALLER_COMP Jens Axboe
2023-07-21 16:29   ` Darrick J. Wong
2023-07-21 16:16 ` [PATCH 8/9] iomap: support IOCB_DIO_CALLER_COMP Jens Axboe
2023-07-21 16:16 ` [PATCH 9/9] iomap: use an unsigned type for IOMAP_DIO_* defines Jens Axboe
2023-07-21 16:29   ` Darrick J. Wong
2023-07-24 16:36   ` Christoph Hellwig

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