Commit 71fc3f5e authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Jens Axboe
Browse files

block: don't try to poll multi-bio I/Os in __blkdev_direct_IO 



If an iocb is split into multiple bios we can't poll for both.  So don't
even bother to try to poll in that case.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211012111226.760968-3-hch@lst.de


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 94c2ed58

block/fops.c

+7 −14
Original line number Diff line number Diff line
@@ -197,7 +197,7 @@ static ssize_t __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, 
	struct blk_plug plug;

	struct blkdev_dio *dio;

	struct bio *bio;

	bool is_poll = (iocb->ki_flags & IOCB_HIPRI) != 0;

	bool do_poll = (iocb->ki_flags & IOCB_HIPRI);

	bool is_read = (iov_iter_rw(iter) == READ), is_sync;

	loff_t pos = iocb->ki_pos;

	blk_qc_t qc = BLK_QC_T_NONE;
@@ -226,7 +226,7 @@ static ssize_t __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, 
	 * Don't plug for HIPRI/polled IO, as those should go straight

	 * to issue

	 */

	if (!is_poll)

	if (!(iocb->ki_flags & IOCB_HIPRI))

		blk_start_plug(&plug);



	for (;;) {
@@ -260,20 +260,13 @@ static ssize_t __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, 


		nr_pages = bio_iov_vecs_to_alloc(iter, BIO_MAX_VECS);

		if (!nr_pages) {

			bool polled = false;



			if (iocb->ki_flags & IOCB_HIPRI) {

			if (do_poll)

				bio_set_polled(bio, iocb);

				polled = true;

			}



			qc = submit_bio(bio);



			if (polled)

			if (do_poll)

				WRITE_ONCE(iocb->ki_cookie, qc);

			break;

		}



		if (!dio->multi_bio) {

			/*

			 * AIO needs an extra reference to ensure the dio
@@ -284,6 +277,7 @@ static ssize_t __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, 
				bio_get(bio);

			dio->multi_bio = true;

			atomic_set(&dio->ref, 2);

			do_poll = false;

		} else {

			atomic_inc(&dio->ref);

		}
@@ -292,7 +286,7 @@ static ssize_t __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, 
		bio = bio_alloc(GFP_KERNEL, nr_pages);

	}



	if (!is_poll)

	if (!(iocb->ki_flags & IOCB_HIPRI))

		blk_finish_plug(&plug);



	if (!is_sync)
@@ -303,8 +297,7 @@ static ssize_t __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, 
		if (!READ_ONCE(dio->waiter))

			break;



		if (!(iocb->ki_flags & IOCB_HIPRI) ||

		    !blk_poll(bdev_get_queue(bdev), qc, true))

		if (!do_poll || !blk_poll(bdev_get_queue(bdev), qc, true))

			blk_io_schedule();

	}

	__set_current_state(TASK_RUNNING);