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Commit 7b6620d7 authored by Jens Axboe's avatar Jens Axboe
Browse files

block: remove REQ_NOWAIT_INLINE 



We had a few issues with this code, and there's still a problem around
how we deal with error handling for chained/split bios. For now, just
revert the code and we'll try again with a thoroug solution. This
reverts commits:

e15c2ffa ("block: fix O_DIRECT error handling for bio fragments")
0eb6ddfb ("block: Fix __blkdev_direct_IO() for bio fragments")
6a43074e ("block: properly handle IOCB_NOWAIT for async O_DIRECT IO")
893a1c97 ("blk-mq: allow REQ_NOWAIT to return an error inline")

Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 99c79f66

block/blk-mq.c

+2 −6
Original line number Diff line number Diff line
@@ -1958,13 +1958,9 @@ static blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio) 
	rq = blk_mq_get_request(q, bio, &data);

	if (unlikely(!rq)) {

		rq_qos_cleanup(q, bio);



		cookie = BLK_QC_T_NONE;

		if (bio->bi_opf & REQ_NOWAIT_INLINE)

			cookie = BLK_QC_T_EAGAIN;

		else if (bio->bi_opf & REQ_NOWAIT)

		if (bio->bi_opf & REQ_NOWAIT)

			bio_wouldblock_error(bio);

		return cookie;

		return BLK_QC_T_NONE;

	}



	trace_block_getrq(q, bio, bio->bi_opf);

fs/block_dev.c

+5 −44
Original line number Diff line number Diff line
@@ -345,24 +345,15 @@ __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, int nr_pages) 
	struct bio *bio;

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

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

	bool nowait = (iocb->ki_flags & IOCB_NOWAIT) != 0;

	loff_t pos = iocb->ki_pos;

	blk_qc_t qc = BLK_QC_T_NONE;

	gfp_t gfp;

	int ret;

	int ret = 0;



	if ((pos | iov_iter_alignment(iter)) &

	    (bdev_logical_block_size(bdev) - 1))

		return -EINVAL;



	if (nowait)

		gfp = GFP_NOWAIT;

	else

		gfp = GFP_KERNEL;



	bio = bio_alloc_bioset(gfp, nr_pages, &blkdev_dio_pool);

	if (!bio)

		return -EAGAIN;

	bio = bio_alloc_bioset(GFP_KERNEL, nr_pages, &blkdev_dio_pool);



	dio = container_of(bio, struct blkdev_dio, bio);

	dio->is_sync = is_sync = is_sync_kiocb(iocb);
@@ -384,7 +375,6 @@ __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, int nr_pages) 
	if (!is_poll)

		blk_start_plug(&plug);



	ret = 0;

	for (;;) {

		bio_set_dev(bio, bdev);

		bio->bi_iter.bi_sector = pos >> 9;
@@ -409,14 +399,7 @@ __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, int nr_pages) 
			task_io_account_write(bio->bi_iter.bi_size);

		}



		/*

		 * Tell underlying layer to not block for resource shortage.

		 * And if we would have blocked, return error inline instead

		 * of through the bio->bi_end_io() callback.

		 */

		if (nowait)

			bio->bi_opf |= (REQ_NOWAIT | REQ_NOWAIT_INLINE);



		dio->size += bio->bi_iter.bi_size;

		pos += bio->bi_iter.bi_size;



		nr_pages = iov_iter_npages(iter, BIO_MAX_PAGES);
@@ -428,13 +411,7 @@ __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, int nr_pages) 
				polled = true;

			}



			dio->size += bio->bi_iter.bi_size;

			qc = submit_bio(bio);

			if (qc == BLK_QC_T_EAGAIN) {

				dio->size -= bio->bi_iter.bi_size;

				ret = -EAGAIN;

				goto error;

			}



			if (polled)

				WRITE_ONCE(iocb->ki_cookie, qc);
@@ -455,19 +432,8 @@ __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, int nr_pages) 
			atomic_inc(&dio->ref);

		}



		dio->size += bio->bi_iter.bi_size;

		qc = submit_bio(bio);

		if (qc == BLK_QC_T_EAGAIN) {

			dio->size -= bio->bi_iter.bi_size;

			ret = -EAGAIN;

			goto error;

		}



		bio = bio_alloc(gfp, nr_pages);

		if (!bio) {

			ret = -EAGAIN;

			goto error;

		}

		submit_bio(bio);

		bio = bio_alloc(GFP_KERNEL, nr_pages);

	}



	if (!is_poll)
@@ -487,7 +453,6 @@ __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, int nr_pages) 
	}

	__set_current_state(TASK_RUNNING);



out:

	if (!ret)

		ret = blk_status_to_errno(dio->bio.bi_status);

	if (likely(!ret))
@@ -495,10 +460,6 @@ __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, int nr_pages) 


	bio_put(&dio->bio);

	return ret;

error:

	if (!is_poll)

		blk_finish_plug(&plug);

	goto out;

}



static ssize_t

include/linux/blk_types.h

+1 −4
Original line number Diff line number Diff line
@@ -311,7 +311,6 @@ enum req_flag_bits { 
	__REQ_RAHEAD,		/* read ahead, can fail anytime */

	__REQ_BACKGROUND,	/* background IO */

	__REQ_NOWAIT,           /* Don't wait if request will block */

	__REQ_NOWAIT_INLINE,	/* Return would-block error inline */

	/*

	 * When a shared kthread needs to issue a bio for a cgroup, doing

	 * so synchronously can lead to priority inversions as the kthread
@@ -346,7 +345,6 @@ enum req_flag_bits { 
#define REQ_RAHEAD		(1ULL << __REQ_RAHEAD)

#define REQ_BACKGROUND		(1ULL << __REQ_BACKGROUND)

#define REQ_NOWAIT		(1ULL << __REQ_NOWAIT)

#define REQ_NOWAIT_INLINE	(1ULL << __REQ_NOWAIT_INLINE)

#define REQ_CGROUP_PUNT		(1ULL << __REQ_CGROUP_PUNT)



#define REQ_NOUNMAP		(1ULL << __REQ_NOUNMAP)
@@ -420,13 +418,12 @@ static inline int op_stat_group(unsigned int op) 


typedef unsigned int blk_qc_t;

#define BLK_QC_T_NONE		-1U

#define BLK_QC_T_EAGAIN		-2U

#define BLK_QC_T_SHIFT		16

#define BLK_QC_T_INTERNAL	(1U << 31)



static inline bool blk_qc_t_valid(blk_qc_t cookie)

{

	return cookie != BLK_QC_T_NONE && cookie != BLK_QC_T_EAGAIN;

	return cookie != BLK_QC_T_NONE;

}



static inline unsigned int blk_qc_t_to_queue_num(blk_qc_t cookie)