path: root/drivers/md/dm-zoned-target.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2017 Western Digital Corporation or its affiliates.
 *
 * This file is released under the GPL.
 */

#include "dm-zoned.h"

#include <linux/module.h>

#define	DM_MSG_PREFIX		"zoned"

#define DMZ_MIN_BIOS		8192

/*
 * Zone BIO context.
 */
struct dmz_bioctx {
	struct dmz_dev		*dev;
	struct dm_zone		*zone;
	struct bio		*bio;
	refcount_t		ref;
};

/*
 * Chunk work descriptor.
 */
struct dm_chunk_work {
	struct work_struct	work;
	refcount_t		refcount;
	struct dmz_target	*target;
	unsigned int		chunk;
	struct bio_list		bio_list;
};

/*
 * Target descriptor.
 */
struct dmz_target {
	struct dm_dev		**ddev;
	unsigned int		nr_ddevs;

	unsigned int		flags;

	/* Zoned block device information */
	struct dmz_dev		*dev;

	/* For metadata handling */
	struct dmz_metadata     *metadata;

	/* For chunk work */
	struct radix_tree_root	chunk_rxtree;
	struct workqueue_struct *chunk_wq;
	struct mutex		chunk_lock;

	/* For cloned BIOs to zones */
	struct bio_set		bio_set;

	/* For flush */
	spinlock_t		flush_lock;
	struct bio_list		flush_list;
	struct delayed_work	flush_work;
	struct workqueue_struct *flush_wq;
};

/*
 * Flush intervals (seconds).
 */
#define DMZ_FLUSH_PERIOD	(10 * HZ)

/*
 * Target BIO completion.
 */
static inline void dmz_bio_endio(struct bio *bio, blk_status_t status)
{
	struct dmz_bioctx *bioctx =
		dm_per_bio_data(bio, sizeof(struct dmz_bioctx));

	if (status != BLK_STS_OK && bio->bi_status == BLK_STS_OK)
		bio->bi_status = status;
	if (bioctx->dev && bio->bi_status != BLK_STS_OK)
		bioctx->dev->flags |= DMZ_CHECK_BDEV;

	if (refcount_dec_and_test(&bioctx->ref)) {
		struct dm_zone *zone = bioctx->zone;

		if (zone) {
			if (bio->bi_status != BLK_STS_OK &&
			    bio_op(bio) == REQ_OP_WRITE &&
			    dmz_is_seq(zone))
				set_bit(DMZ_SEQ_WRITE_ERR, &zone->flags);
			dmz_deactivate_zone(zone);
		}
		bio_endio(bio);
	}
}

/*
 * Completion callback for an internally cloned target BIO. This terminates the
 * target BIO when there are no more references to its context.
 */
static void dmz_clone_endio(struct bio *clone)
{
	struct dmz_bioctx *bioctx = clone->bi_private;
	blk_status_t status = clone->bi_status;

	bio_put(clone);
	dmz_bio_endio(bioctx->bio, status);
}

/*
 * Issue a clone of a target BIO. The clone may only partially process the
 * original target BIO.
 */
static int dmz_submit_bio(struct dmz_target *dmz, struct dm_zone *zone,
			  struct bio *bio, sector_t chunk_block,
			  unsigned int nr_blocks)
{
	struct dmz_bioctx *bioctx =
		dm_per_bio_data(bio, sizeof(struct dmz_bioctx));
	struct dmz_dev *dev = zone->dev;
	struct bio *clone;

	if (dev->flags & DMZ_BDEV_DYING)
		return -EIO;

	clone = bio_clone_fast(bio, GFP_NOIO, &dmz->bio_set);
	if (!clone)
		return -ENOMEM;

	bio_set_dev(clone, dev->bdev);
	bioctx->dev = dev;
	clone->bi_iter.bi_sector =
		dmz_start_sect(dmz->metadata, zone) + dmz_blk2sect(chunk_block);
	clone->bi_iter.bi_size = dmz_blk2sect(nr_blocks) << SECTOR_SHIFT;
	clone->bi_end_io = dmz_clone_endio;
	clone->bi_private = bioctx;

	bio_advance(bio, clone->bi_iter.bi_size);

	refcount_inc(&bioctx->ref);
	submit_bio_noacct(clone);

	if (bio_op(bio) == REQ_OP_WRITE && dmz_is_seq(zone))
		zone->wp_block += nr_blocks;

	return 0;
}

/*
 * Zero out pages of discarded blocks accessed by a read BIO.
 */
static void dmz_handle_read_zero(struct dmz_target *dmz, struct bio *bio,
				 sector_t chunk_block, unsigned int nr_blocks)
{
	unsigned int