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dm-zone.c
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dm-zone.c
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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2021 Western Digital Corporation or its affiliates.
*/
#include <linux/blkdev.h>
#include <linux/mm.h>
#include <linux/sched/mm.h>
#include <linux/slab.h>
#include "dm-core.h"
#define DM_MSG_PREFIX "zone"
#define DM_ZONE_INVALID_WP_OFST UINT_MAX
/*
* For internal zone reports bypassing the top BIO submission path.
*/
static int dm_blk_do_report_zones(struct mapped_device *md, struct dm_table *t,
sector_t sector, unsigned int nr_zones,
report_zones_cb cb, void *data)
{
struct gendisk *disk = md->disk;
int ret;
struct dm_report_zones_args args = {
.next_sector = sector,
.orig_data = data,
.orig_cb = cb,
};
do {
struct dm_target *tgt;
tgt = dm_table_find_target(t, args.next_sector);
if (WARN_ON_ONCE(!tgt->type->report_zones))
return -EIO;
args.tgt = tgt;
ret = tgt->type->report_zones(tgt, &args,
nr_zones - args.zone_idx);
if (ret < 0)
return ret;
} while (args.zone_idx < nr_zones &&
args.next_sector < get_capacity(disk));
return args.zone_idx;
}
/*
* User facing dm device block device report zone operation. This calls the
* report_zones operation for each target of a device table. This operation is
* generally implemented by targets using dm_report_zones().
*/
int dm_blk_report_zones(struct gendisk *disk, sector_t sector,
unsigned int nr_zones, report_zones_cb cb, void *data)
{
struct mapped_device *md = disk->private_data;
struct dm_table *map;
int srcu_idx, ret;
if (dm_suspended_md(md))
return -EAGAIN;
map = dm_get_live_table(md, &srcu_idx);
if (!map)
return -EIO;
ret = dm_blk_do_report_zones(md, map, sector, nr_zones, cb, data);
dm_put_live_table(md, srcu_idx);
return ret;
}
static int dm_report_zones_cb(struct blk_zone *zone, unsigned int idx,
void *data)
{
struct dm_report_zones_args *args = data;
sector_t sector_diff = args->tgt->begin - args->start;
/*
* Ignore zones beyond the target range.
*/
if (zone->start >= args->start + args->tgt->len)
return 0;
/*
* Remap the start sector and write pointer position of the zone
* to match its position in the target range.
*/
zone->start += sector_diff;
if (zone->type != BLK_ZONE_TYPE_CONVENTIONAL) {
if (zone->cond == BLK_ZONE_COND_FULL)
zone->wp = zone->start + zone->len;
else if (zone->cond == BLK_ZONE_COND_EMPTY)
zone->wp = zone->start;
else
zone->wp += sector_diff;
}
args->next_sector = zone->start + zone->len;
return args->orig_cb(zone, args->zone_idx++, args->orig_data);
}
/*
* Helper for drivers of zoned targets to implement struct target_type
* report_zones operation.
*/
int dm_report_zones(struct block_device *bdev, sector_t start, sector_t sector,
struct dm_report_zones_args *args, unsigned int nr_zones)
{
/*
* Set the target mapping start sector first so that
* dm_report_zones_cb() can correctly remap zone information.
*/
args->start = start;
return blkdev_report_zones(bdev, sector, nr_zones,
dm_report_zones_cb, args);
}
EXPORT_SYMBOL_GPL(dm_report_zones);
bool dm_is_zone_write(struct mapped_device *md, struct bio *bio)
{
struct request_queue *q = md->queue;
if (!blk_queue_is_zoned(q))
return false;
switch (bio_op(bio)) {
case REQ_OP_WRITE_ZEROES:
case REQ_OP_WRITE:
return !op_is_flush(bio->bi_opf) && bio_sectors(bio);
default:
return false;
}
}
void dm_cleanup_zoned_dev(struct mapped_device *md)
{
struct request_queue *q = md->queue;
if (q) {
kfree(q->conv_zones_bitmap);
q->conv_zones_bitmap = NULL;
kfree(q->seq_zones_wlock);
q->seq_zones_wlock = NULL;
}
kvfree(md->zwp_offset);
md->zwp_offset = NULL;
md->nr_zones = 0;
}
static unsigned int dm_get_zone_wp_offset(struct blk_zone *zone)
{
switch (zone->cond) {
case BLK_ZONE_COND_IMP_OPEN:
case BLK_ZONE_COND_EXP_OPEN:
case BLK_ZONE_COND_CLOSED:
return zone->wp - zone->start;
case BLK_ZONE_COND_FULL:
return zone->len;
case BLK_ZONE_COND_EMPTY:
case BLK_ZONE_COND_NOT_WP:
case BLK_ZONE_COND_OFFLINE:
case BLK_ZONE_COND_READONLY:
default:
/*
* Conventional, offline and read-only zones do not have a valid
* write pointer. Use 0 as for an empty zone.
*/
return 0;
}
}
static int dm_zone_revalidate_cb(struct blk_zone *zone, unsigned int idx,
void *data)
{
struct mapped_device *md = data;
struct request_queue *q = md->queue;
switch (zone->type) {
case BLK_ZONE_TYPE_CONVENTIONAL:
if (!q->conv_zones_bitmap) {
q->conv_zones_bitmap =
kcalloc(BITS_TO_LONGS(q->nr_zones),
sizeof(unsigned long), GFP_NOIO);
if (!q->conv_zones_bitmap)
return -ENOMEM;
}
set_bit(idx, q->conv_zones_bitmap);
break;
case BLK_ZONE_TYPE_SEQWRITE_REQ:
case BLK_ZONE_TYPE_SEQWRITE_PREF:
if (!q->seq_zones_wlock) {
q->seq_zones_wlock =
kcalloc(BITS_TO_LONGS(q->nr_zones),
sizeof(unsigned long), GFP_NOIO);
if (!q->seq_zones_wlock)
return -ENOMEM;
}
if (!md->zwp_offset) {
md->zwp_offset =
kvcalloc(q->nr_zones, sizeof(unsigned int),
GFP_KERNEL);
if (!md->zwp_offset)
return -ENOMEM;
}
md->zwp_offset[idx] = dm_get_zone_wp_offset(zone);
break;
default:
DMERR("Invalid zone type 0x%x at sectors %llu",
(int)zone->type, zone->start);
return -ENODEV;
}
return 0;
}
/*
* Revalidate the zones of a mapped device to initialize resource necessary
* for zone append emulation. Note that we cannot simply use the block layer
* blk_revalidate_disk_zones() function here as the mapped device is suspended
* (this is called from __bind() context).
*/
static int dm_revalidate_zones(struct mapped_device *md, struct dm_table *t)
{
struct request_queue *q = md->queue;
unsigned int noio_flag;
int ret;
/*
* Check if something changed. If yes, cleanup the current resources
* and reallocate everything.
*/
if (!q->nr_zones || q->nr_zones != md->nr_zones)
dm_cleanup_zoned_dev(md);
if (md->nr_zones)
return 0;
/*
* Scan all zones to initialize everything. Ensure that all vmalloc
* operations in this context are done as if GFP_NOIO was specified.
*/
noio_flag = memalloc_noio_save();
ret = dm_blk_do_report_zones(md, t, 0, q->nr_zones,
dm_zone_revalidate_cb, md);
memalloc_noio_restore(noio_flag);
if (ret < 0)
goto err;
if (ret != q->nr_zones) {
ret = -EIO;
goto err;
}
md->nr_zones = q->nr_zones;
return 0;
err:
DMERR("Revalidate zones failed %d", ret);
dm_cleanup_zoned_dev(md);
return ret;
}
static int device_not_zone_append_capable(struct dm_target *ti,
struct dm_dev *dev, sector_t start,
sector_t len, void *data)
{
return !blk_queue_is_zoned(bdev_get_queue(dev->bdev));
}
static bool dm_table_supports_zone_append(struct dm_table *t)
{
struct dm_target *ti;
unsigned int i;
for (i = 0; i < dm_table_get_num_targets(t); i++) {
ti = dm_table_get_target(t, i);
if (ti->emulate_zone_append)
return false;
if (!ti->type->iterate_devices ||
ti->type->iterate_devices(ti, device_not_zone_append_capable, NULL))
return false;
}
return true;
}
int dm_set_zones_restrictions(struct dm_table *t, struct request_queue *q)
{
struct mapped_device *md = t->md;
/*
* For a zoned target, the number of zones should be updated for the
* correct value to be exposed in sysfs queue/nr_zones.
*/
WARN_ON_ONCE(queue_is_mq(q));
q->nr_zones = blkdev_nr_zones(md->disk);
/* Check if zone append is natively supported */
if (dm_table_supports_zone_append(t)) {
clear_bit(DMF_EMULATE_ZONE_APPEND, &md->flags);
dm_cleanup_zoned_dev(md);
return 0;
}
/*
* Mark the mapped device as needing zone append emulation and
* initialize the emulation resources once the capacity is set.
*/
set_bit(DMF_EMULATE_ZONE_APPEND, &md->flags);
if (!get_capacity(md->disk))
return 0;
return dm_revalidate_zones(md, t);
}
static int dm_update_zone_wp_offset_cb(struct blk_zone *zone, unsigned int idx,
void *data)
{
unsigned int *wp_offset = data;
*wp_offset = dm_get_zone_wp_offset(zone);
return 0;
}
static int dm_update_zone_wp_offset(struct mapped_device *md, unsigned int zno,
unsigned int *wp_ofst)
{
sector_t sector = zno * blk_queue_zone_sectors(md->queue);
unsigned int noio_flag;
struct dm_table *t;
int srcu_idx, ret;
t = dm_get_live_table(md, &srcu_idx);
if (!t)
return -EIO;
/*
* Ensure that all memory allocations in this context are done as if
* GFP_NOIO was specified.
*/
noio_flag = memalloc_noio_save();
ret = dm_blk_do_report_zones(md, t, sector, 1,
dm_update_zone_wp_offset_cb, wp_ofst);
memalloc_noio_restore(noio_flag);
dm_put_live_table(md, srcu_idx);
if (ret != 1)
return -EIO;
return 0;
}
struct orig_bio_details {
unsigned int op;
unsigned int nr_sectors;
};
/*
* First phase of BIO mapping for targets with zone append emulation:
* check all BIO that change a zone writer pointer and change zone
* append operations into regular write operations.
*/
static bool dm_zone_map_bio_begin(struct mapped_device *md,
unsigned int zno, struct bio *clone)
{
sector_t zsectors = blk_queue_zone_sectors(md->queue);
unsigned int zwp_offset = READ_ONCE(md->zwp_offset[zno]);
/*
* If the target zone is in an error state, recover by inspecting the
* zone to get its current write pointer position. Note that since the
* target zone is already locked, a BIO issuing context should never
* see the zone write in the DM_ZONE_UPDATING_WP_OFST state.
*/
if (zwp_offset == DM_ZONE_INVALID_WP_OFST) {
if (dm_update_zone_wp_offset(md, zno, &zwp_offset))
return false;
WRITE_ONCE(md->zwp_offset[zno], zwp_offset);
}
switch (bio_op(clone)) {
case REQ_OP_ZONE_RESET:
case REQ_OP_ZONE_FINISH:
return true;
case REQ_OP_WRITE_ZEROES:
case REQ_OP_WRITE:
/* Writes must be aligned to the zone write pointer */
if ((clone->bi_iter.bi_sector & (zsectors - 1)) != zwp_offset)
return false;
break;
case REQ_OP_ZONE_APPEND:
/*
* Change zone append operations into a non-mergeable regular
* writes directed at the current write pointer position of the
* target zone.
*/
clone->bi_opf = REQ_OP_WRITE | REQ_NOMERGE |
(clone->bi_opf & (~REQ_OP_MASK));
clone->bi_iter.bi_sector += zwp_offset;
break;
default:
DMWARN_LIMIT("Invalid BIO operation");
return false;
}
/* Cannot write to a full zone */
if (zwp_offset >= zsectors)
return false;
return true;
}
/*
* Second phase of BIO mapping for targets with zone append emulation:
* update the zone write pointer offset array to account for the additional
* data written to a zone. Note that at this point, the remapped clone BIO
* may already have completed, so we do not touch it.
*/
static blk_status_t dm_zone_map_bio_end(struct mapped_device *md, unsigned int zno,
struct orig_bio_details *orig_bio_details,
unsigned int nr_sectors)
{
unsigned int zwp_offset = READ_ONCE(md->zwp_offset[zno]);
/* The clone BIO may already have been completed and failed */
if (zwp_offset == DM_ZONE_INVALID_WP_OFST)
return BLK_STS_IOERR;
/* Update the zone wp offset */
switch (orig_bio_details->op) {
case REQ_OP_ZONE_RESET:
WRITE_ONCE(md->zwp_offset[zno], 0);
return BLK_STS_OK;
case REQ_OP_ZONE_FINISH:
WRITE_ONCE(md->zwp_offset[zno],
blk_queue_zone_sectors(md->queue));
return BLK_STS_OK;
case REQ_OP_WRITE_ZEROES:
case REQ_OP_WRITE:
WRITE_ONCE(md->zwp_offset[zno], zwp_offset + nr_sectors);
return BLK_STS_OK;
case REQ_OP_ZONE_APPEND:
/*
* Check that the target did not truncate the write operation
* emulating a zone append.
*/
if (nr_sectors != orig_bio_details->nr_sectors) {
DMWARN_LIMIT("Truncated write for zone append");
return BLK_STS_IOERR;
}
WRITE_ONCE(md->zwp_offset[zno], zwp_offset + nr_sectors);
return BLK_STS_OK;
default:
DMWARN_LIMIT("Invalid BIO operation");
return BLK_STS_IOERR;
}
}
static inline void dm_zone_lock(struct request_queue *q,
unsigned int zno, struct bio *clone)
{
if (WARN_ON_ONCE(bio_flagged(clone, BIO_ZONE_WRITE_LOCKED)))
return;
wait_on_bit_lock_io(q->seq_zones_wlock, zno, TASK_UNINTERRUPTIBLE);
bio_set_flag(clone, BIO_ZONE_WRITE_LOCKED);
}
static inline void dm_zone_unlock(struct request_queue *q,
unsigned int zno, struct bio *clone)
{
if (!bio_flagged(clone, BIO_ZONE_WRITE_LOCKED))
return;
WARN_ON_ONCE(!test_bit(zno, q->seq_zones_wlock));
clear_bit_unlock(zno, q->seq_zones_wlock);
smp_mb__after_atomic();
wake_up_bit(q->seq_zones_wlock, zno);
bio_clear_flag(clone, BIO_ZONE_WRITE_LOCKED);
}
static bool dm_need_zone_wp_tracking(struct bio *bio)
{
/*
* Special processing is not needed for operations that do not need the
* zone write lock, that is, all operations that target conventional
* zones and all operations that do not modify directly a sequential
* zone write pointer.
*/
if (op_is_flush(bio->bi_opf) && !bio_sectors(bio))
return false;
switch (bio_op(bio)) {
case REQ_OP_WRITE_ZEROES:
case REQ_OP_WRITE:
case REQ_OP_ZONE_RESET:
case REQ_OP_ZONE_FINISH:
case REQ_OP_ZONE_APPEND:
return bio_zone_is_seq(bio);
default:
return false;
}
}
/*
* Special IO mapping for targets needing zone append emulation.
*/
int dm_zone_map_bio(struct dm_target_io *tio)
{
struct dm_io *io = tio->io;
struct dm_target *ti = tio->ti;
struct mapped_device *md = io->md;
struct request_queue *q = md->queue;
struct bio *clone = &tio->clone;
struct orig_bio_details orig_bio_details;
unsigned int zno;
blk_status_t sts;
int r;
/*
* IOs that do not change a zone write pointer do not need
* any additional special processing.
*/
if (!dm_need_zone_wp_tracking(clone))
return ti->type->map(ti, clone);
/* Lock the target zone */
zno = bio_zone_no(clone);
dm_zone_lock(q, zno, clone);
orig_bio_details.nr_sectors = bio_sectors(clone);
orig_bio_details.op = bio_op(clone);
/*
* Check that the bio and the target zone write pointer offset are
* both valid, and if the bio is a zone append, remap it to a write.
*/
if (!dm_zone_map_bio_begin(md, zno, clone)) {
dm_zone_unlock(q, zno, clone);
return DM_MAPIO_KILL;
}
/*
* The target map function may issue and complete the IO quickly.
* Take an extra reference on the IO to make sure it does disappear
* until we run dm_zone_map_bio_end().
*/
dm_io_inc_pending(io);
/* Let the target do its work */
r = ti->type->map(ti, clone);
switch (r) {
case DM_MAPIO_SUBMITTED:
/*
* The target submitted the clone BIO. The target zone will
* be unlocked on completion of the clone.
*/
sts = dm_zone_map_bio_end(md, zno, &orig_bio_details,
*tio->len_ptr);
break;
case DM_MAPIO_REMAPPED:
/*
* The target only remapped the clone BIO. In case of error,
* unlock the target zone here as the clone will not be
* submitted.
*/
sts = dm_zone_map_bio_end(md, zno, &orig_bio_details,
*tio->len_ptr);
if (sts != BLK_STS_OK)
dm_zone_unlock(q, zno, clone);
break;
case DM_MAPIO_REQUEUE:
case DM_MAPIO_KILL:
default:
dm_zone_unlock(q, zno, clone);
sts = BLK_STS_IOERR;
break;
}
/* Drop the extra reference on the IO */
dm_io_dec_pending(io, sts);
if (sts != BLK_STS_OK)
return DM_MAPIO_KILL;
return r;
}
/*
* IO completion callback called from clone_endio().
*/
void dm_zone_endio(struct dm_io *io, struct bio *clone)
{
struct mapped_device *md = io->md;
struct request_queue *q = md->queue;
struct bio *orig_bio = io->orig_bio;
unsigned int zwp_offset;
unsigned int zno;
/*
* For targets that do not emulate zone append, we only need to
* handle native zone-append bios.
*/
if (!dm_emulate_zone_append(md)) {
/*
* Get the offset within the zone of the written sector
* and add that to the original bio sector position.
*/
if (clone->bi_status == BLK_STS_OK &&
bio_op(clone) == REQ_OP_ZONE_APPEND) {
sector_t mask = (sector_t)blk_queue_zone_sectors(q) - 1;
orig_bio->bi_iter.bi_sector +=
clone->bi_iter.bi_sector & mask;
}
return;
}
/*
* For targets that do emulate zone append, if the clone BIO does not
* own the target zone write lock, we have nothing to do.
*/
if (!bio_flagged(clone, BIO_ZONE_WRITE_LOCKED))
return;
zno = bio_zone_no(orig_bio);
if (clone->bi_status != BLK_STS_OK) {
/*
* BIOs that modify a zone write pointer may leave the zone
* in an unknown state in case of failure (e.g. the write
* pointer was only partially advanced). In this case, set
* the target zone write pointer as invalid unless it is
* already being updated.
*/
WRITE_ONCE(md->zwp_offset[zno], DM_ZONE_INVALID_WP_OFST);
} else if (bio_op(orig_bio) == REQ_OP_ZONE_APPEND) {
/*
* Get the written sector for zone append operation that were
* emulated using regular write operations.
*/
zwp_offset = READ_ONCE(md->zwp_offset[zno]);
if (WARN_ON_ONCE(zwp_offset < bio_sectors(orig_bio)))
WRITE_ONCE(md->zwp_offset[zno],
DM_ZONE_INVALID_WP_OFST);
else
orig_bio->bi_iter.bi_sector +=
zwp_offset - bio_sectors(orig_bio);
}
dm_zone_unlock(q, zno, clone);
}