While creating new device with NVM_DEV_CREATE if LUNs are already
allocated ioctl would return -ENOMEM which is wrong.  This patch
propagates -EBUSY from nvm_reserve_luns which is correct response.

Fixes: ade69e24 ("lightnvm: merge gennvm with core")
Reviewed-by: NFrans Klaver <fransklaver@gmail.com>
Signed-off-by: NRakesh Pandit <rakesh@tuxera.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Due to user writes being decoupled from media writes because of the need
of an intermediate write buffer, irrecoverable media write errors lead
to pblk stalling; user writes fill up the buffer and end up in an
infinite retry loop.

In order to let user writes fail gracefully, it is necessary for pblk to
keep track of its own internal state and prevent further writes from
being placed into the write buffer.

This patch implements a state machine to keep track of internal errors
and, in case of failure, fail further user writes in an standard way.
Depending on the type of error, pblk will do its best to persist
buffered writes (which are already acknowledged) and close down on a
graceful manner. This way, data might be recovered by re-instantiating
pblk. Such state machine paves out the way for a state-based FTL log.
Signed-off-by: NJavier González <javier@cnexlabs.com>
Signed-off-by: NMatias Bjørling <matias@cnexlabs.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Make constants to define sizes for internal mempools and workqueues. In
this process, adjust the values to be more meaningful given the internal
constrains of the FTL. In order to do this for workqueues, separate the
current auxiliary workqueue into two dedicated workqueues to manage
lines being closed and bad blocks.
Signed-off-by: NJavier González <javier@cnexlabs.com>
Signed-off-by: NMatias Bjørling <matias@cnexlabs.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

At the moment, in order to get enough read parallelism, we have recycled
several lines at the same time. This approach has proven not to work
well when reaching capacity, since we end up mixing valid data from all
lines, thus not maintaining a sustainable free/recycled line ratio.

The new design, relies on a two level workqueue mechanism. In the first
level, we read the metadata for a number of lines based on the GC list
they reside on (this is governed by the number of valid sectors in each
line). In the second level, we recycle a single line at a time. Here, we
issue reads in parallel, while a single GC write thread places data in
the write buffer. This design allows to (i) only move data from one line
at a time, thus maintaining a sane free/recycled ration and (ii)
maintain the GC writer busy with recycled data.
Signed-off-by: NJavier González <javier@cnexlabs.com>
Signed-off-by: NMatias Bjørling <matias@cnexlabs.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Add lockdep assertions on helper functions.
Signed-off-by: NJavier González <javier@cnexlabs.com>
Signed-off-by: NMatias Bjørling <matias@cnexlabs.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Cleanup unnecessary headers and code lines.
Signed-off-by: NJavier González <javier@cnexlabs.com>
Signed-off-by: NMatias Bjørling <matias@cnexlabs.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Set a dma area for all I/Os in order to read/write from/to the metadata
stored on the per-sector out-of-bound area.
Signed-off-by: NJavier González <javier@cnexlabs.com>
Signed-off-by: NMatias Bjørling <matias@cnexlabs.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

At the moment, we separate the closed lines on three different list
based on their number of valid sectors. GC recycles lines from each list
based on capacity. Lines from each list are taken in a FIFO fashion.

Since the number of lines is limited (it corresponds to the number of
blocks in a LUN, which is somewhere between 1000-2000), we can afford
scanning the lists to choose the optimal line to be recycled. This helps
specially in lines with a high number of valid sectors.

If the number of blocks per LUN increases, we will consider a more
efficient policy.
Signed-off-by: NJavier González <javier@cnexlabs.com>
Signed-off-by: NMatias Bjørling <matias@cnexlabs.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Decouple bad block discovery from line allocation logic. This allows to
return meaningful error codes in case of bad block discovery failure.
Signed-off-by: NJavier González <javier@cnexlabs.com>
Signed-off-by: NMatias Bjørling <matias@cnexlabs.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

smeta size will always be suitable for a kmalloc allocation. Simplify
the code and leave the vmalloc fallback only for emeta, where the pblk
configuration has an impact.
Signed-off-by: NJavier González <javier@cnexlabs.com>
Signed-off-by: NMatias Bjørling <matias@cnexlabs.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

If a read request is sequential and its size aligns with a
multi-plane page size, use the multi-plane hint to process the I/O in
parallel in the controller.
Signed-off-by: NJavier González <javier@cnexlabs.com>
Signed-off-by: NMatias Bjørling <matias@cnexlabs.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

After refactoring the metadata path, the backpointer controlling
synced I/Os in a line becomes unnecessary; metadata is scheduled
on the write thread, thus we know when the end of the line is reached
and act on it directly.
Signed-off-by: NJavier González <javier@cnexlabs.com>
Signed-off-by: NMatias Bjørling <matias@cnexlabs.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Remove a legacy variable that helped verifying the consistency of the
run-time metadata for the free line list. With the new metadata layout,
this check is no longer necessary.
Signed-off-by: NJavier González <javier@cnexlabs.com>
Signed-off-by: NMatias Bjørling <matias@cnexlabs.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

At the moment, line metadata is persisted on a separate work queue, that
is kicked each time that a line is closed. The assumption when designing
this was that freeing the write thread from creating a new write request
was better than the potential impact of writes colliding on the media
(user I/O and metadata I/O). Experimentation has proven that this
assumption is wrong; collision can cause up to 25% of bandwidth and
introduce long tail latencies on the write thread, which potentially
cause user write threads to spend more time spinning to get a free entry
on the write buffer.

This patch moves the metadata logic to the write thread. When a line is
closed, remaining metadata is written in memory and is placed on a
metadata queue. The write thread then takes the metadata corresponding
to the previous line, creates the write request and schedules it to
minimize collisions on the media. Using this approach, we see that we
can saturate the media's bandwidth, which helps reducing both write
latencies and the spinning time for user writer threads.
Signed-off-by: NJavier González <javier@cnexlabs.com>
Signed-off-by: NMatias Bjørling <matias@cnexlabs.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Read requests allocate some extra memory to store its per I/O context.
Instead of requiring yet another memory pool for other type of requests,
generalize this context allocation (and change naming accordingly).
Signed-off-by: NJavier González <javier@cnexlabs.com>
Signed-off-by: NMatias Bjørling <matias@cnexlabs.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Erase I/Os are scheduled with the following goals in mind: (i) minimize
LUNs collisions with write I/Os, and (ii) even out the price of erasing
on every write, instead of putting all the burden on when garbage
collection runs. This works well on the current design, but is specific
to the default mapping algorithm.

This patch generalizes the erase path so that other mapping algorithms
can select an arbitrary line to be erased instead. It also gets rid of
the erase semaphore since it creates jittering for user writes.
Signed-off-by: NJavier González <javier@cnexlabs.com>
Signed-off-by: NMatias Bjørling <matias@cnexlabs.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Allow to configure the number of maximum sectors per write command
through sysfs. This makes it easier to tune write command sizes for
different controller configurations.
Signed-off-by: NJavier González <javier@cnexlabs.com>
Signed-off-by: NMatias Bjørling <matias@cnexlabs.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Add a new debug counter to measure cache hits on the read path
Signed-off-by: NJavier González <javier@cnexlabs.com>
Signed-off-by: NMatias Bjørling <matias@cnexlabs.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Spare a double calculation on the fast write path.
Signed-off-by: NJavier González <javier@cnexlabs.com>
Signed-off-by: NMatias Bjørling <matias@cnexlabs.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

In case of a failure when submitting a request, convert the ppa_list
addresses to the target format so that it can interpret ppas for
recovery
Signed-off-by: NJavier González <javier@cnexlabs.com>
Signed-off-by: NMatias Bjørling <matias@cnexlabs.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

pblk_submit_read() uses bio_clone_bioset() but doesn't change the
io_vec, so bio_clone_fast() is a better choice.

It also uses fs_bio_set which is intended for filesystems.  Using it
in a device driver can deadlock.
So allocate a new bioset, and and use bio_clone_fast().
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NJavier González <javier@cnexlabs.com>
Tested-by: NJavier González <javier@cnexlabs.com>
Signed-off-by: NNeilBrown <neilb@suse.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

blk_queue_split() is always called with the last arg being q->bio_split,
where 'q' is the first arg.

Also blk_queue_split() sometimes uses the passed-in 'bs' and sometimes uses
q->bio_split.

This is inconsistent and unnecessary.  Remove the last arg and always use
q->bio_split inside blk_queue_split()
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NMing Lei <ming.lei@redhat.com>
Credit-to: Javier González <jg@lightnvm.io> (Noticed that lightnvm was missed)
Reviewed-by: NJavier González <javier@cnexlabs.com>
Tested-by: NJavier González <javier@cnexlabs.com>
Signed-off-by: NNeilBrown <neilb@suse.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Replace bi_error with a new bi_status to allow for a clear conversion.
Note that device mapper overloaded bi_error with a private value, which
we'll have to keep arround at least for now and thus propagate to a
proper blk_status_t value.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@fb.com>

Free memory correctly when an allocation fails on a loop and we free
backwards previously successful allocations.
Signed-off-by: NJavier González <javier@cnexlabs.com>
Reviewed-by: NMatias Bjørling <matias@cnexlabs.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@fb.com>

'blks' is malloced in pblk_bb_discovery() and should be freed
before leaving from the nvm_get_tgt_bb_tbl() error handling cases,
otherwise it will cause memory leak. Also skip assign blks to
rlun->bb_list when error.

Fixes: a4bd217b ("lightnvm: physical block device (pblk) target")
Signed-off-by: NWei Yongjun <weiyongjun1@huawei.com>
Reviewed-by: NJavier González <javier@cnexlabs.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

When block erases fail, these blocks are marked bad. The number of valid
blocks in the line was not updated, which could cause an infinite loop
on the erase path.

Fix this atomic counter and, in order to avoid taking an irq lock on the
interrupt context, make the erase counters atomic too.

Also, in the case that a significant number of blocks become bad in a
line, the result is the double shared metadata buffer (emeta) to stop
the pipeline until all metadata is flushed to the media. Increase the
number of metadata lines from 2 to 4 to avoid this case.

Fixes: a4bd217b "lightnvm: physical block device (pblk) target"
Signed-off-by: NJavier González <javier@cnexlabs.com>
Reviewed-by: NMatias Bjørling <matias@cnexlabs.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

When a line allocation fails, for example, due to having too many bad
blocks, free its metadata correctly.

Fixes: a4bd217b "lightnvm: physical block device (pblk) target"
Signed-off-by: NJavier González <javier@cnexlabs.com>
Reviewed-by: NMatias Bjørling <matias@cnexlabs.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

When write recovery fails, Free memory for the recovery structure.

Fixes: a4bd217b "lightnvm: physical block device (pblk) target"
Signed-off-by: NJavier González <javier@cnexlabs.com>
Reviewed-by: NMatias Bjørling <matias@cnexlabs.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

Fix bad error check

Fixes: a4bd217b "lightnvm: physical block device (pblk) target"
Signed-off-by: NJavier González <javier@cnexlabs.com>
Reviewed-by: NMatias Bjørling <matias@cnexlabs.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

When a pblk line fails (or is recovered), make sure to take the line
management lock.

Fixes: a4bd217b "lightnvm: physical block device (pblk) target"
Signed-off-by: NJavier González <javier@cnexlabs.com>
Reviewed-by: NMatias Bjørling <matias@cnexlabs.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

Reading from ADDR_EMPTY is out of bounds.  The current code generates a
static checker warning because we check for out of bounds "lba" before
we check for ADDR_EMPTY, so the second check is always false.  It looks
like we intended ADDR_EMPTY to be a no-op without printing a warning.

Fixes: a4bd217b ("lightnvm: physical block device (pblk) target")
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: NJavier González <javier@cnexlabs.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

This is a static checker fix, and perhaps not a real bug.  The static
checker thinks that nr_secs could be negative.  It would result in
zeroing more memory than intended.  Anyway, even if it's not a bug,
changing this variable to unsigned makes the code easier to audit.

Fixes: a4bd217b ("lightnvm: physical block device (pblk) target")
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: NJavier González <javier@cnexlabs.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

From userspace calling ioctl(NVM_DEV_CREATE) was returning ENOMEM for
invalid arguments even though pblk (pblk_init) was returning correctly
-EINVAL to nvm_create_tgt inside core.  This patch propagates the
correct return value to userspace.

Because pblk was introduced recently this only needs to go in 4.12.

Fixes: a4bd217b ("lightnvm: physical block device (pblk) target")
Signed-off-by: NRakesh Pandit <rakesh@tuxera.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

On an error path in NVM_DEV_CREATE ioctl blk_put_queue is being called
twice: one via blk_cleanup_queue and another via put_disk.  Straight fix
seems to remove queue pointer so that disk_release never ends up caling
blk_put_queue again.

  [  391.808827] WARNING: CPU: 1 PID: 1250 at lib/refcount.c:128 refcount_sub_and_test+0x70/0x80
  [  391.808830] refcount_t: underflow; use-after-free.
  [ 391.808832] Modules linked in: nf_conntrack_netbios_ns............
  [  391.809052] CPU: 1 PID: 1250 Comm: nvme Not tainted.........
  [  391.809057] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
             BIOS rel-1.7.5-0-ge51488c-20140602_164612-nilsson.home.kraxel.org 04/01/2014
  [  391.809060] Call Trace:
  [  391.809079]  dump_stack+0x63/0x86
  [  391.809094]  __warn+0xcb/0xf0
  [  391.809103]  warn_slowpath_fmt+0x5f/0x80
  [  391.809118]  refcount_sub_and_test+0x70/0x80
  [  391.809125]  refcount_dec_and_test+0x11/0x20
  [  391.809136]  kobject_put+0x1f/0x60
  [  391.809149]  blk_put_queue+0x15/0x20
  [  391.809159]  disk_release+0xae/0xf0
  [  391.809172]  device_release+0x32/0x90
  [  391.809184]  kobject_release+0x6a/0x170
  [  391.809196]  kobject_put+0x2f/0x60
  [  391.809206]  put_disk+0x17/0x20
  [  391.809219]  nvm_ioctl_dev_create.isra.16+0x897/0xa30
  [  391.809236]  nvm_ctl_ioctl+0x23c/0x4c0
  [  391.809248]  do_vfs_ioctl+0xa3/0x5f0
  [  391.809258]  SyS_ioctl+0x79/0x90
  [  391.809271]  entry_SYSCALL_64_fastpath+0x1a/0xa9
  [  391.809280] RIP: 0033:0x7f5d3ef363c7
  [  391.809286] RSP: 002b:00007ffc72ed8d78 EFLAGS: 00000206 ORIG_RAX: 0000000000000010
  [  391.809296] RAX: ffffffffffffffda RBX: 00007ffc72edb552 RCX: 00007f5d3ef363c7
  [  391.809301] RDX: 00007ffc72ed8d90 RSI: 0000000040804c22 RDI: 0000000000000003
  [  391.809306] RBP: 0000000000000001 R08: 0000000000000020 R09: 0000000000000001
  [  391.809311] R10: 000000000000053f R11: 0000000000000206 R12: 0000000000000000
  [  391.809316] R13: 0000000000000000 R14: 00007ffc72edb58d R15: 00007ffc72edb581
Signed-off-by: NRakesh Pandit <rakesh@tuxera.com>
Reviewed-by: NMatias Bjørling <matias@cnexlabs.com>
Fixes: 7d1ef2f4 "lightnvm: fix cleanup order of disk on init error"
Signed-off-by: NJens Axboe <axboe@fb.com>

The driver uses both u64 and sector_t to refer to offsets, and assigns between the
two. This causes one harmless warning when sector_t is 32-bit:

drivers/lightnvm/pblk-rb.c: In function 'pblk_rb_write_entry_gc':
include/linux/lightnvm.h:215:20: error: large integer implicitly truncated to unsigned type [-Werror=overflow]
drivers/lightnvm/pblk-rb.c:324:22: note: in expansion of macro 'ADDR_EMPTY'

As the driver is already doing this inconsistently, changing the type
won't make it worse and is an easy way to avoid the warning.

Fixes: a4bd217b ("lightnvm: physical block device (pblk) target")
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NJens Axboe <axboe@fb.com>

There were a bunch of places in pblk_lines_init() where we didn't set an
error code.  And in pblk_writer_init() we accidentally return 1 instead
of a correct error code, which would result in a Oops later.

Fixes: 11a5d6fdf919 ("lightnvm: physical block device (pblk) target")
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NMatias Bjørling <matias@cnexlabs.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

WARN_ON() takes a condition, not an error message.  I slightly tweaked
some conditions so hopefully it's more clear.
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NMatias Bjørling <matias@cnexlabs.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

These labels are reversed so we could end up dereferencing an error
pointer or leaking.

Fixes: 7f347ba6bb3a ("lightnvm: physical block device (pblk) target")
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NMatias Bjørling <matias@cnexlabs.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

This patch introduces pblk, a host-side translation layer for
Open-Channel SSDs to expose them like block devices. The translation
layer allows data placement decisions, and I/O scheduling to be
managed by the host, enabling users to optimize the SSD for their
specific workloads.

An open-channel SSD has a set of LUNs (parallel units) and a
collection of blocks. Each block can be read in any order, but
writes must be sequential. Writes may also fail, and if a block
requires it, must also be reset before new writes can be
applied.

To manage the constraints, pblk maintains a logical to
physical address (L2P) table,  write cache, garbage
collection logic, recovery scheme, and logic to rate-limit
user I/Os versus garbage collection I/Os.

The L2P table is fully-associative and manages sectors at a
4KB granularity. Pblk stores the L2P table in two places, in
the out-of-band area of the media and on the last page of a
line. In the cause of a power failure, pblk will perform a
scan to recover the L2P table.

The user data is organized into lines. A line is data
striped across blocks and LUNs. The lines enable the host to
reduce the amount of metadata to maintain besides the user
data and makes it easier to implement RAID or erasure coding
in the future.

pblk implements multi-tenant support and can be instantiated
multiple times on the same drive. Each instance owns a
portion of the SSD - both regarding I/O bandwidth and
capacity - providing I/O isolation for each case.

Finally, pblk also exposes a sysfs interface that allows
user-space to peek into the internals of pblk. The interface
is available at /dev/block/*/pblk/ where * is the block
device name exposed.

This work also contains contributions from:
  Matias Bjørling <matias@cnexlabs.com>
  Simon A. F. Lund <slund@cnexlabs.com>
  Young Tack Jin <youngtack.jin@gmail.com>
  Huaicheng Li <huaicheng@cs.uchicago.edu>
Signed-off-by: NJavier González <javier@cnexlabs.com>
Signed-off-by: NMatias Bjørling <matias@cnexlabs.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

Convert sprintf calls to strlcpy in order to make possible buffer
overflow more obvious.
Signed-off-by: NJavier González <javier@cnexlabs.com>
Signed-off-by: NMatias Bjørling <matias@cnexlabs.com>
Signed-off-by: NJens Axboe <axboe@fb.com>