linux-toradex.git/drivers/lightnvm/pblk-read.c, branch v5.3-rc1

lightnvm: pblk: simplify partial read path

2019-05-06T16:19:19+00:00

This patch changes the approach to handling partial read path.

In old approach merging of data from round buffer and drive was fully
made by drive. This had some disadvantages - code was complex and
relies on bio internals, so it was hard to maintain and was strongly
dependent on bio changes.

In new approach most of the handling is done mostly by block layer
functions such as bio_split(), bio_chain() and generic_make request()
and generally is less complex and easier to maintain. Below some more
details of the new approach.

When read bio arrives, it is cloned for pblk internal purposes. All
the L2P mapping, which includes copying data from round buffer to bio
and thus bio_advance() calls is done on the cloned bio, so the original
bio is untouched. If we found that we have partial read case, we
still have original bio untouched, so we can split it and continue to
process only first part of it in current context, when the rest will be
called as separate bio request which is passed to generic_make_request()
for further processing.

Signed-off-by: Igor Konopko 
Reviewed-by: Heiner Litz 
Reviewed-by: Javier González 
Signed-off-by: Matias Bjørling 
Signed-off-by: Jens Axboe

lightnvm: pblk: IO path reorganization

2019-05-06T16:19:19+00:00

This patch is made in order to prepare read path for new approach to
partial read handling, which is simpler in compare with previous one.

The most important change is to move the handling of completed and
failed bio from the pblk_make_rq() to particular read and write
functions. This is needed, since after partial read path changes,
sometimes completed/failed bio will be different from original one, so
we cannot do this any longer in pblk_make_rq().

Other changes are small read path refactor in order to reduce the size
of the following patch with partial read changes.

Generally the goal of this patch is not to change the functionality,
but just to prepare the code for the following changes.

Signed-off-by: Igor Konopko 
Reviewed-by: Javier González 
Signed-off-by: Matias Bjørling 
Signed-off-by: Jens Axboe

lightnvm: pblk: GC error handling

2019-05-06T16:19:18+00:00

Currently when there is an IO error (or similar) on GC read path, pblk
still move the line, which was currently under GC process to free state.
Such a behaviour can lead to silent data mismatch issue.

With this patch, the line which was under GC process on which some IO
errors occurred, will be putted back to closed state (instead of free
state as it was without this patch) and the L2P mapping for such a
failed sectors will not be updated.

Then in case of any user IOs to such a failed sectors, pblk would be
able to return at least real IO error instead of stale data as it is
right now.

Signed-off-by: Igor Konopko 
Reviewed-by: Javier González 
Reviewed-by: Hans Holmberg 
Signed-off-by: Matias Bjørling 
Signed-off-by: Jens Axboe

lightnvm: pblk: set proper read status in bio

2019-05-06T16:19:17+00:00

Currently in case of read errors, bi_status is not set properly which
leads to returning inproper data to layers above. This patch fix that
by setting proper status in case of read errors.

Also remove unnecessary warn_once(), which does not make sense
in that place, since user bio is not used for interation with drive
and thus bi_status will not be set here.

Signed-off-by: Igor Konopko 
Reviewed-by: Javier González 
Reviewed-by: Hans Holmberg 
Signed-off-by: Matias Bjørling 
Signed-off-by: Jens Axboe

lightnvm: pblk: reduce L2P memory footprint

2019-05-06T16:19:16+00:00

Currently L2P map size is calculated based on the total number of
available sectors, which is redundant, since it contains mapping for
overprovisioning as well (11% by default).

Change this size to the real capacity and thus reduce the memory
footprint significantly - with default op value it is approx.
110MB of DRAM less for every 1TB of media.

Signed-off-by: Igor Konopko 
Reviewed-by: Hans Holmberg 
Reviewed-by: Javier González 
Signed-off-by: Matias Bjørling 
Signed-off-by: Jens Axboe

lightnvm: pblk: fix crash in pblk_end_partial_read due to multipage bvecs

2019-04-10T18:17:01+00:00

The introduction of multipage bio vectors broke pblk's partial read
logic due to it not being prepared for multipage bio vectors.

Use bio vector iterators instead of direct bio vector indexing.

Fixes: 07173c3ec276 ("block: enable multipage bvecs")
Reported-by: Klaus Jensen 
Signed-off-by: Hans Holmberg 
Updated description.
Signed-off-by: Matias Bjørling 
Signed-off-by: Jens Axboe

lightnvm: pblk: support packed metadata

2018-12-11T19:22:35+00:00

pblk performs recovery of open lines by storing the LBA in the per LBA
metadata field. Recovery therefore only works for drives that has this
field.

This patch adds support for packed metadata, which store l2p mapping
for open lines in last sector of every write unit and enables drives
without per IO metadata to recover open lines.

After this patch, drives with OOB size <16B will use packed metadata
and metadata size larger than16B will continue to use the device per
IO metadata.

Reviewed-by: Javier González 
Signed-off-by: Igor Konopko 
Signed-off-by: Matias Bjørling 
Signed-off-by: Jens Axboe

lightnvm: pblk: add helpers for OOB metadata

2018-12-11T19:22:35+00:00

pblk currently assumes that size of OOB metadata on drive is always
equal to size of pblk_sec_meta struct. This commit add helpers which will
allow to handle different sizes of OOB metadata on drive in the future.

After this patch only OOB metadata equal to 16 bytes is supported.

Reviewed-by: Javier González 
Signed-off-by: Igor Konopko 
Signed-off-by: Matias Bjørling 
Signed-off-by: Jens Axboe

lightnvm: pblk: move lba list to partial read context

2018-12-11T19:22:34+00:00

Currently DMA allocated memory is reused on partial read
for lba_list_mem and lba_list_media arrays. In preparation
for dynamic DMA pool sizes we need to move this arrays
into pblk_pr_ctx structures.

Reviewed-by: Javier González 
Signed-off-by: Igor Konopko 
Signed-off-by: Matias Bjørling 
Signed-off-by: Jens Axboe

lightnvm: pblk: add SPDX license tag

2018-10-09T14:25:08+00:00

Add GLP-2.0 SPDX license tag to all pblk files

Signed-off-by: Javier González 
Signed-off-by: Matias Bjørling 
Signed-off-by: Jens Axboe