/*
* 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_target *target;
struct dm_zone *zone;
struct bio *bio;
atomic_t ref;
blk_status_t status;
};
/*
* Chunk work descriptor.
*/
struct dm_chunk_work {
struct work_struct work;
atomic_t refcount;
struct dmz_target *target;
unsigned int chunk;
struct bio_list bio_list;
};
/*
* Target descriptor.
*/
struct dmz_target {
struct dm_dev *ddev;
unsigned long flags;
/* Zoned block device information */
struct dmz_dev *dev;
/* For metadata handling */
struct dmz_metadata *metadata;
/* For reclaim */
struct dmz_reclaim *reclaim;
/* For chunk work */
struct mutex chunk_lock;
struct radix_tree_root chunk_rxtree;
struct workqueue_struct *chunk_wq;
/* 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 (bioctx->status == BLK_STS_OK && status != BLK_STS_OK)
bioctx->status = status;
bio_endio(bio);
}
/*
* Partial clone read BIO completion callback. This terminates the
* target BIO when there are no more references to its context.
*/
static void dmz_read_bio_end_io(struct bio *bio)
{
struct dmz_bioctx *bioctx = bio->bi_private;
blk_status_t status = bio->bi_status;
bio_put(bio);
dmz_bio_endio(bioctx->bio, status);
}
/*
* Issue a BIO to a zone. The BIO may only partially process the
* original target BIO.
*/
static int dmz_submit_read_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));
sector_t sector;
struct bio *clone;
/* BIO remap sector */
sector = dmz_start_sect(dmz->metadata, zone) + dmz_blk2sect(chunk_block);
/* If the read is not partial, there is no need to clone the BIO */
if (nr_blocks == dmz_bio_blocks(bio)) {
/* Setup and submit the BIO */
bio->bi_iter.bi_sector = sector;
atomic_inc(&bioctx->ref);
generic_make_request(bio);
return 0;
}
/* Partial BIO: we need to clone the BIO */
clone = bio_clone_fast(bio, GFP_NOIO, dmz->bio_set);
if (!clone)
return -ENOMEM;
/* Setup the clone */
clone->bi_iter.bi_sector = sector;
clone->bi_iter.bi_size = dmz_blk2sect(nr_blocks) << SECTOR_SHIFT;
clone->bi_end_io = dmz_read_bio_end_io;
clone->bi_private = bioctx;
bio_advance(bio, clone->bi_iter.bi_size);
/* Submit the clone */
atomic_inc(&bioctx->ref);
generic_make_request(clone);
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 size = nr_blocks << DMZ_BLOCK_SHIFT;
/* Clear nr_blocks */
swap(bio->bi_iter.bi_size, size);
zero_fill_bio(bio);
swap(bio->bi_iter.bi_size, size);
bio_advance(bio, size);
}
/*
* Process a read BIO.
*/
static int dmz_handle_read(struct dmz_target *dmz, struct dm_zone *zone,
struct bio *bio)
{
sector_t chunk_block = dmz_chunk_block(dmz->dev, dmz_bio_block(bio));
unsigned int nr_blocks = dmz_bio_blocks(bio);
sector_t end_block = chunk_block + nr_blocks;
struct dm_zone *rzone, *bzone;
int ret;
/* Read into unmapped chunks need only zeroing the BIO buffer */
if (!zone) {
zero_fill_bio(bio);
return 0;
}
dmz_dev_debug(dmz->dev, "READ chunk %llu -> %s zone %u, block %llu, %u blocks",