Add support for NVM Express Zoned Namespaces (ZNS) Command Set defined
in NVM Express TP4053. Zoned namespaces are discovered based on their
Command Set Identifier reported in the namespaces Namespace
Identification Descriptor list. A successfully discovered Zoned
Namespace will be registered with the block layer as a host managed
zoned block device with Zone Append command support. A namespace that
does not support append is not supported by the driver.
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: NJohannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Reviewed-by: NJavier González <javier.gonz@samsung.com>
Reviewed-by: NHimanshu Madhani <himanshu.madhani@oracle.com>
Signed-off-by: NHans Holmberg <hans.holmberg@wdc.com>
Signed-off-by: NDmitry Fomichev <dmitry.fomichev@wdc.com>
Signed-off-by: NAjay Joshi <ajay.joshi@wdc.com>
Signed-off-by: NAravind Ramesh <aravind.ramesh@wdc.com>
Signed-off-by: NNiklas Cassel <niklas.cassel@wdc.com>
Signed-off-by: NMatias Bjørling <matias.bjorling@wdc.com>
Signed-off-by: NDamien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: NKeith Busch <keith.busch@wdc.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

The Commands Supported and Effects log page was extended with a CSI
field that enables the host to query the log page for each command set
supported. Retrieve this log page for each command set that an attached
namespace supports, and save a pointer to that log in the namespace head.
Reviewed-by: NMatias Bjørling <matias.bjorling@wdc.com>
Reviewed-by: NJavier González <javier.gonz@samsung.com>
Reviewed-by: NHimanshu Madhani <himanshu.madhani@oracle.com>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Reviewed-by: NJohannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: NDaniel Wagner <dwagner@suse.de>
Signed-off-by: NKeith Busch <keith.busch@wdc.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Implements support for multiple I/O Command Sets.  NVMe TP 4056
introduces a method to enumerate multiple command sets per namespace. If
the command set is exposed, this method for enumeration will be used
instead of the traditional method that uses the CC.CSS register command
set register for command set identification.

For namespaces where the Command Set Identifier is not supported or
recognized, the specific namespace will not be created.
Reviewed-by: NJavier González <javier.gonz@samsung.com>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: NJohannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: NMatias Bjørling <matias.bjorling@wdc.com>
Reviewed-by: NDaniel Wagner <dwagner@suse.de>
Reviewed-by: NHimanshu Madhani <himanshu.madhani@oracle.com>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NNiklas Cassel <niklas.cassel@wdc.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Use USEC_PER_SEC instead of magic numbers to make code more readable.
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NBaolin Wang <baolin.wang@linux.alibaba.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

In nvme_init_identify() when calculating submission queue size use u16
instead of int type in the min_t() since target variable ctrl->sqsize is
of type u16.
Signed-off-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

In nvme_configure_directives() when calculating number of streams use
u16 instead of unsigned type in the min_t() since target variable
ctrl->nr_streams is of type u16.
Signed-off-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Commit 59c7c3ca intended to only silently ignore non retry-able
errors (DNR bit set) such that we can still identify misbehaving
controllers, and in the other hand propagate retry-able errors (DNR bit
cleared) so we don't wrongly abandon a namespace just because it happens
to be temporarily inaccessible.

The goal remains the same as the original commit where this was
introduced but unfortunately had the logic backwards.

Fixes: 59c7c3ca ("nvme: fix possible hang when ns scanning fails during error recovery")
Reported-by: NKeith Busch <kbusch@kernel.org>
Signed-off-by: NSagi Grimberg <sagi@grimberg.me>
Reviewed-by: NKeith Busch <kbusch@kernel.org>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

The make_request_fn is a little weird in that it sits directly in
struct request_queue instead of an operation vector.  Replace it with
a block_device_operations method called submit_bio (which describes much
better what it does).  Also remove the request_queue argument to it, as
the queue can be derived pretty trivially from the bio.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Revert fab7772b ("nvme-multipath: revalidate nvme_ns_head gendisk
in nvme_validate_ns")

When adding a new namespace to the head disk (via nvme_mpath_set_live)
we will see partition scan which triggers I/O on the mpath device node.
This process will usually be triggered from the scan_work which holds
the scan_lock. If I/O blocks (if we got ana change currently have only
available paths but none are accessible) this can deadlock on the head
disk bd_mutex as both partition scan I/O takes it, and head disk revalidation
takes it to check for resize (also triggered from scan_work on a different
path). See trace [1].

The mpath disk revalidation was originally added to detect online disk
size change, but this is no longer needed since commit cb224c3a
("nvme: Convert to use set_capacity_revalidate_and_notify") which already
updates resize info without unnecessarily revalidating the disk (the
mpath disk doesn't even implement .revalidate_disk fop).

[1]:
--
kernel: INFO: task kworker/u65:9:494 blocked for more than 241 seconds.
kernel:       Tainted: G           OE     5.3.5-050305-generic #201910071830
kernel: "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
kernel: kworker/u65:9   D    0   494      2 0x80004000
kernel: Workqueue: nvme-wq nvme_scan_work [nvme_core]
kernel: Call Trace:
kernel:  __schedule+0x2b9/0x6c0
kernel:  schedule+0x42/0xb0
kernel:  schedule_preempt_disabled+0xe/0x10
kernel:  __mutex_lock.isra.0+0x182/0x4f0
kernel:  __mutex_lock_slowpath+0x13/0x20
kernel:  mutex_lock+0x2e/0x40
kernel:  revalidate_disk+0x63/0xa0
kernel:  __nvme_revalidate_disk+0xfe/0x110 [nvme_core]
kernel:  nvme_revalidate_disk+0xa4/0x160 [nvme_core]
kernel:  ? evict+0x14c/0x1b0
kernel:  revalidate_disk+0x2b/0xa0
kernel:  nvme_validate_ns+0x49/0x940 [nvme_core]
kernel:  ? blk_mq_free_request+0xd2/0x100
kernel:  ? __nvme_submit_sync_cmd+0xbe/0x1e0 [nvme_core]
kernel:  nvme_scan_work+0x24f/0x380 [nvme_core]
kernel:  process_one_work+0x1db/0x380
kernel:  worker_thread+0x249/0x400
kernel:  kthread+0x104/0x140
kernel:  ? process_one_work+0x380/0x380
kernel:  ? kthread_park+0x80/0x80
kernel:  ret_from_fork+0x1f/0x40
...
kernel: INFO: task kworker/u65:1:2630 blocked for more than 241 seconds.
kernel:       Tainted: G           OE     5.3.5-050305-generic #201910071830
kernel: "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
kernel: kworker/u65:1   D    0  2630      2 0x80004000
kernel: Workqueue: nvme-wq nvme_scan_work [nvme_core]
kernel: Call Trace:
kernel:  __schedule+0x2b9/0x6c0
kernel:  schedule+0x42/0xb0
kernel:  io_schedule+0x16/0x40
kernel:  do_read_cache_page+0x438/0x830
kernel:  ? __switch_to_asm+0x34/0x70
kernel:  ? file_fdatawait_range+0x30/0x30
kernel:  read_cache_page+0x12/0x20
kernel:  read_dev_sector+0x27/0xc0
kernel:  read_lba+0xc1/0x220
kernel:  ? kmem_cache_alloc_trace+0x19c/0x230
kernel:  efi_partition+0x1e6/0x708
kernel:  ? vsnprintf+0x39e/0x4e0
kernel:  ? snprintf+0x49/0x60
kernel:  check_partition+0x154/0x244
kernel:  rescan_partitions+0xae/0x280
kernel:  __blkdev_get+0x40f/0x560
kernel:  blkdev_get+0x3d/0x140
kernel:  __device_add_disk+0x388/0x480
kernel:  device_add_disk+0x13/0x20
kernel:  nvme_mpath_set_live+0x119/0x140 [nvme_core]
kernel:  nvme_update_ns_ana_state+0x5c/0x60 [nvme_core]
kernel:  nvme_set_ns_ana_state+0x1e/0x30 [nvme_core]
kernel:  nvme_parse_ana_log+0xa1/0x180 [nvme_core]
kernel:  ? nvme_update_ns_ana_state+0x60/0x60 [nvme_core]
kernel:  nvme_mpath_add_disk+0x47/0x90 [nvme_core]
kernel:  nvme_validate_ns+0x396/0x940 [nvme_core]
kernel:  ? blk_mq_free_request+0xd2/0x100
kernel:  nvme_scan_work+0x24f/0x380 [nvme_core]
kernel:  process_one_work+0x1db/0x380
kernel:  worker_thread+0x249/0x400
kernel:  kthread+0x104/0x140
kernel:  ? process_one_work+0x380/0x380
kernel:  ? kthread_park+0x80/0x80
kernel:  ret_from_fork+0x1f/0x40
--

Fixes: fab7772b ("nvme-multipath: revalidate nvme_ns_head gendisk
in nvme_validate_ns")
Signed-off-by: NAnton Eidelman <anton@lightbitslabs.com>
Signed-off-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Initialize the node to NUMA_NO_NODE value. Transports that are aware of
numa node affinity can override it (e.g. RDMA transport set the affinity
according to the RDMA HCA).
Signed-off-by: NMax Gurtovoy <maxg@mellanox.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Move the call to blk_should_fake_timeout out of blk_mq_complete_request
and into the drivers, skipping call sites that are obvious error
handlers, and remove the now superflous blk_mq_force_complete_rq helper.
This ensures we don't keep injecting errors into completions that just
terminate the Linux request after the hardware has been reset or the
command has been aborted.
Reviewed-by: NDaniel Wagner <dwagner@suse.de>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

device_add_disk() is negated by del_gendisk().
alloc_disk_node() is negated by put_disk().

In nvme_alloc_ns(), device_add_disk() is one of the last things being
called in the success case, and only void functions are being called
after this. Therefore this call should not be negated in the error path.

The superfluous call to del_gendisk() leads to the following prints:
[    7.839975] kobject: '(null)' (000000001ff73734): is not initialized, yet kobject_put() is being called.
[    7.840865] WARNING: CPU: 2 PID: 361 at lib/kobject.c:736 kobject_put+0x70/0x120

Fixes: 33cfdc2a ("nvme: enforce extended LBA format for fabrics metadata")
Signed-off-by: NNiklas Cassel <niklas.cassel@wdc.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Reviewed-by: NMax Gurtovoy <maxg@mellanox.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Use blk_mq_foce_complete_rq() to bypass fake timeout error injection so
that request reclaim may proceed.
Signed-off-by: NKeith Busch <kbusch@kernel.org>
Reviewed-by: NJohannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: NMing Lei <ming.lei@redhat.com>
Reviewed-by: NDaniel Wagner <dwagner@suse.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

The default dma alignment mask is 511, which is much larger than any nvme
controller requires. NVMe controllers accept qword aligned DMA addresses,
so set the request_queue constraints to that. This can help avoid bounce
buffers on user passthrough commands.
Signed-off-by: NKeith Busch <kbusch@kernel.org>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

An extended LBA is a larger LBA that is created when metadata associated
with the LBA is transferred contiguously with the LBA data (AKA
interleaved). The metadata may be either transferred as part of the LBA
(creating an extended LBA) or it may be transferred as a separate
contiguous buffer of data. According to the NVMeoF spec, a fabrics ctrl
supports only an Extended LBA format. Fail revalidation in case we have a
spec violation. Also add a flag that will imply on capable transports and
controllers as part of a preparation for allowing end-to-end protection
information for fabric controllers.
Suggested-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NMax Gurtovoy <maxg@mellanox.com>
Signed-off-by: NIsrael Rukshin <israelr@mellanox.com>
Reviewed-by: NJames Smart <james.smart@broadcom.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

This patch doesn't change any logic, and is needed as a preparation
for adding PI support for fabrics drivers that will use an extended
LBA format for metadata and will support more than 1 integrity segment.
Signed-off-by: NMax Gurtovoy <maxg@mellanox.com>
Signed-off-by: NIsrael Rukshin <israelr@mellanox.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: NJames Smart <james.smart@broadcom.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Move the nvme_ns_has_pi() inline from core.c to the nvme.h header.
This allows use by the transports.
Signed-off-by: NJames Smart <jsmart2021@gmail.com>
[maxg: added a comment for nvme_ns_has_pi()]
Signed-off-by: NMax Gurtovoy <maxg@mellanox.com>
Reviewed-by: NIsrael Rukshin <israelr@mellanox.com>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

This is a preparation for adding support for metadata in fabric
controllers. New flag will imply that NVMe namespace supports getting
metadata that was originally generated by host's block layer.
Signed-off-by: NMax Gurtovoy <maxg@mellanox.com>
Reviewed-by: NIsrael Rukshin <israelr@mellanox.com>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: NJames Smart <james.smart@broadcom.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Replace the specific ext boolean (that implies on extended LBA format)
with a feature in the new namespace features flag. This is a preparation
for adding more namespace features (such as metadata specific features).
Signed-off-by: NMax Gurtovoy <maxg@mellanox.com>
Reviewed-by: NIsrael Rukshin <israelr@mellanox.com>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: NJames Smart <james.smart@broadcom.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Currently, a namespace io_opt queue limit is set by default to the
physical sector size of the namespace and to the the write optimal
size (NOWS) when the namespace reports optimal IO sizes. This causes
problems with block limits stacking in blk_stack_limits() when a
namespace block device is combined with an HDD which generally do not
report any optimal transfer size (io_opt limit is 0). The code:

/* Optimal I/O a multiple of the physical block size? */
if (t->io_opt & (t->physical_block_size - 1)) {
	t->io_opt = 0;
	t->misaligned = 1;
	ret = -1;
}

in blk_stack_limits() results in an error return for this function when
the combined devices have different but compatible physical sector
sizes (e.g. 512B sector SSD with 4KB sector disks).

Fix this by not setting the optimal IO size queue limit if the namespace
does not report an optimal write size value.
Signed-off-by: NDamien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: NBart van Assche <bvanassche@acm.org>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Disable streams again if getting the stream params fails.
Signed-off-by: NWu Bo <wubo40@huawei.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Improve code readability by defining the specification's constants that
the driver is using when decoding identification payloads.
Signed-off-by: NKeith Busch <kbusch@kernel.org>
Reviewed-by: NBart van Assche <bvanassche@acm.org>
Reviewed-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Acked-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

If a passthrough command causes the namespace inventory or capabilities
to change, flush the scan work that handles these changes so the driver
synchronizes with the user command's effects before returning the result
to user space.
Signed-off-by: NKeith Busch <kbusch@kernel.org>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Use a common label for putting the nshead if needed and only convert
nvme status codes for the one case where it actually is needed.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NKeith Busch <kbusch@kernel.org>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

The stream parameters indicating optimal io settings were just getting
overwritten later. Rearrange the settings so the streams parameters can
be preserved if provided.
Signed-off-by: NKeith Busch <kbusch@kernel.org>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

The stream parameters are based on the currently formatted logical block
size. Recheck these parameters on namespace revalidation so the
registered constraints will be accurate.
Signed-off-by: NKeith Busch <kbusch@kernel.org>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Move the quirked chunk_sectors setting to the same location as noiob so
one place registers this setting. And since the noiob value is only used
locally, remove the member from struct nvme_ns.
Signed-off-by: NKeith Busch <kbusch@kernel.org>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

If the namespace identifiers have changed, skip updating the disk
information, as that will register parameters from a mismatched
namespace.
Signed-off-by: NKeith Busch <kbusch@kernel.org>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

The queues' backing device info capabilities don't change with each
namespace revalidation. Set it only when each path's request_queue
is initially added to a multipath queue.
Signed-off-by: NKeith Busch <kbusch@kernel.org>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Reject a new shared namespace if a duplicate unshared namespace exists.
Signed-off-by: NKeith Busch <kbusch@kernel.org>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Even if a namespace reports it is not capable of sharing, search the
subsystem for a matching namespace head. If found, the driver should
reject that namespace since it's coming from an invalid configuration.
Signed-off-by: NKeith Busch <kbusch@kernel.org>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

If a namespace identification does not match the subsystem's head for
that NSID, release the reference that was taken when the matching head
was initially found.
Signed-off-by: NKeith Busch <kbusch@kernel.org>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

The driver had been unlinking the namespace head from the subsystem's
list only after the last reference was released, and outside of the
list's subsys->lock protection.

There is no reason to track an empty head, so unlink the entry from the
subsystem's list when the last namespace using that head is removed and
with the mutex lock protecting the list update. The next namespace to
attach reusing the previous NSID will allocate a new head rather than
find the old head with mismatched identifiers.
Signed-off-by: NKeith Busch <kbusch@kernel.org>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Replace it with a value derived from the identify data and nsid sizes.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NKeith Busch <kbusch@kernel.org>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

The namespace lists are 0-terminated, so we don't really need the NN value
execept for the legacy sequential scan.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NKeith Busch <kbusch@kernel.org>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Factor out a piece of deeply indented and logicaly separate code
from nvme_scan_ns_list into a new helper.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NKeith Busch <kbusch@kernel.org>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Move the check for the supported CNS value into nvme_scan_ns_list, and
limit the life time of the identify controller allocation.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NKeith Busch <kbusch@kernel.org>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Add a helper to check if we can use Identify CNS values > 1, and refine
the Qemu quirk to not apply to reported versions larger than 1.1, as the
Qemu implementation had been fixed by then.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NKeith Busch <kbusch@kernel.org>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

nvme_alloc_ns_head() doesn't use the 'struct nvme_id_ns' parameter.
Remove it, and update caller accordingly.
Signed-off-by: NKeith Busch <kbusch@kernel.org>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Various nvme commands use a zeroes based number of dwords field. Create
a helper function to convert byte lengths to this format.
Signed-off-by: NKeith Busch <kbusch@kernel.org>
Reviewed-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>