null_blk: pass queue_limits to blk_mq_alloc_disk

Pass the queue limits directly to blk_mq_alloc_disk instead of
setting them one at a time.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Tested-by: Damien Le Moal <dlemoal@kernel.org>
Link: https://lore.kernel.org/r/20240220093248.3290292-6-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

null_blk: remove the bio based I/O path

The bio based I/O path complicates null_blk and also make various
data structures, including the per-command one way bigger than
required for the main request based interface. As the bio-based
path is mostly used by stacking drivers and simple memory based
drivers, and brd is a good example driver for the latter there is
no need to have a bio based path in null_blk. Remove the path
to simplify the driver and make future block layer API changes
simpler by not having to deal with the complex two API setup in
null_blk.

Note that the queue_mode field in struct nullb_device is kept as
that is simpler than having two different places to check the
value and fully open coding the debugfs helpers as the existing
ones won't work without a named struct member.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Tested-by: Damien Le Moal <dlemoal@kernel.org>
Link: https://lore.kernel.org/r/20240220093248.3290292-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: simplify disk_set_zoned

Only use disk_set_zoned to actually enable zoned device support.
For clearing it, call disk_clear_zoned, which is renamed from
disk_clear_zone_settings and now directly clears the zoned flag as
well.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20231217165359.604246-5-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: remove support for the host aware zone model

When zones were first added the SCSI and ATA specs, two different
models were supported (in addition to the drive managed one that
is invisible to the host):

- host managed where non-conventional zones there is strict requirement
to write at the write pointer, or else an error is returned
- host aware where a write point is maintained if writes always happen
at it, otherwise it is left in an under-defined state and the
sequential write preferred zones behave like conventional zones
(probably very badly performing ones, though)

Not surprisingly this lukewarm model didn't prove to be very useful and
was finally removed from the ZBC and SBC specs (NVMe never implemented
it). Due to to the easily disappearing write pointer host software
could never rely on the write pointer to actually be useful for say
recovery.

Fortunately only a few HDD prototypes shipped using this model which
never made it to mass production. Drop the support before it is too
late. Note that any such host aware prototype HDD can still be used
with Linux as we'll now treat it as a conventional HDD.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20231217165359.604246-4-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

scsi: block: nullblk: Set zone limits before revalidating zones

In null_register_zoned_dev(), execute blk_queue_chunk_sectors() and
blk_queue_max_zone_append_sectors() to respectively set the zoned device
zone size and maximum zone append sector limit before executing
blk_revalidate_disk_zones(). This is to allow the block layer zone
reavlidation to check these device characteristics prior to checking all
zones of the device.

Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Link: https://lore.kernel.org/r/20230703024812.76778-4-dlemoal@kernel.org
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

null_blk: support read-only and offline zone conditions

In zoned mode, zones with write pointers can have conditions "read-only"
or "offline". In read-only condition, zones can not be written. In
offline condition, the zones can be neither written nor read. These
conditions are intended for zones with media failures, then it is
difficult to set those conditions to zones on real devices.

To test handling of zones in the conditions, add a feature to null_blk
to set up zones in read-only or offline condition. Add new configuration
attributes "zone_readonly" and "zone_offline". Write a sector to the
attribute files to specify the target zone to set the zone conditions.
For example, following command lines do it:

echo 0 > nullb1/zone_readonly
echo 524288 > nullb1/zone_offline

When the specified zones are already in read-only or offline condition,
normal empty condition is restored to the zones. These condition changes
can be done only after the null_blk device get powered, since status
area of each zone is not yet allocated before power-on.

Also improve zone condition checks to inhibit all commands for zones in
offline conditions. In same manner, inhibit write and zone management
commands for zones in read-only condition.

Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Link: https://lore.kernel.org/r/20221201061036.2342206-1-shinichiro.kawasaki@wdc.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

treewide: Rename enum req_opf into enum req_op

The type name enum req_opf is misleading since it suggests that values of
this type include both an operation type and flags. Since values of this
type represent an operation only, change the type name into enum req_op.

Convert the enum req_op documentation into kernel-doc format. Move a few
definitions such that the enum req_op documentation occurs just above
the enum req_op definition.

The name "req_opf" was introduced by commit ef295ecf090d ("block: better op
and flags encoding").

Cc: Christoph Hellwig <hch@lst.de>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Damien Le Moal <damien.lemoal@wdc.com>
Cc: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20220714180729.1065367-2-bvanassche@acm.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: move zone related fields to struct gendisk

Move the zone related fields that are currently stored in
struct request_queue to struct gendisk as these are part of the highlevel
block layer API and are only used for non-passthrough I/O that requires
the gendisk.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20220706070350.1703384-17-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: replace blkdev_nr_zones with bdev_nr_zones

Pass a block_device instead of a request_queue as that is what most
callers have at hand.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Acked-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Link: https://lore.kernel.org/r/20220706070350.1703384-12-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: pass a gendisk to blk_queue_max_open_zones and blk_queue_max_active_zones

Switch to a gendisk based API in preparation for moving all zone related
fields from the request_queue to the gendisk.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20220706070350.1703384-11-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: pass a gendisk to blk_queue_set_zoned

Prepare for storing the zone related field in struct gendisk instead
of struct request_queue.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20220706070350.1703384-7-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: null_blk: Fix null_zone_write()

The bio and rq fields of struct nullb_cmd are now overlapping in a
union. So we cannot use a test on ->bio being non-NULL to detect the
NULL_Q_BIO queue mode. null_zone_write() use such broken test to set the
sector position of a zone append write in the command bio or request.
When the null_blk device uses the NULL_Q_MQ queue mode,
null_zone_write() wrongly end up setting the bio sector position,
resulting in the command request to be broken and random crashes
following.

Fix this by testing the device queue mode directly.

Fixes: 8ba816b23abd ("null-blk: save memory footprint for struct nullb_cmd")
Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20220602120344.1365329-1-damien.lemoal@opensource.wdc.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: null_blk: Cleanup messages

Use the pr_fmt() macro to prefix all null_blk pr_xxx() messages with
"null_blk:" to clarify which module is printing the messages. Also add
a pr_info() message in null_add_dev() to print the name of a newly
created disk.

Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20220420005718.3780004-4-damien.lemoal@opensource.wdc.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

drivers/block/null_blk/main: Fix a double free in null_init.

In null_init, null_add_dev(dev) is called.
In null_add_dev, it calls null_free_zoned_dev(dev) to free dev->zones
via kvfree(dev->zones) in out_cleanup_zone branch and returns err.
Then null_init accept the err code and then calls null_free_dev(dev).

But in null_free_dev(dev), dev->zones is freed again by
null_free_zoned_dev().

My patch set dev->zones to NULL in null_free_zoned_dev() after
kvfree(dev->zones) is called, to avoid the double free.

Fixes: 2984c8684f962 ("nullb: factor disk parameters")
Signed-off-by: Lv Yunlong <lyl2019@mail.ustc.edu.cn>
Link: https://lore.kernel.org/r/20210426143229.7374-1-lyl2019@mail.ustc.edu.cn
Signed-off-by: Jens Axboe <axboe@kernel.dk>

nullb: use blk_queue_set_zoned() to setup zoned devices

Use blk_queue_set_zoned() to set a nullb device zone model instead of
directly assigning the device queue zoned limit. This initialization of
the devicve zoned model as well as the setup of the queue flag
QUEUE_FLAG_ZONE_RESETALL and of the device queue elevator feature are
moved from null_init_zoned_dev() to null_register_zoned_dev() so that
the initialization of the queue limits is done when the gendisk of the
nullb device is available.

Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@edc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

null_blk: cleanup zoned mode initialization

To avoid potential compilation problems, replaced the badly written
MB_TO_SECTS() macro (missing parenthesis around the argument use) with
the inline function mb_to_sects(). And while at it, simplify the
calculation of the total number of zones of the device using the
round_up() macro.

Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

null_blk: Move driver into its own directory

Move null_blk driver code into the new sub-directory
drivers/block/null_blk.

Suggested-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>