kernel/git/stable/linux.git/drivers/lightnvm/pblk-rb.c, branch master

remove the lightnvm subsystem

2021-08-14T21:54:09+00:00

Lightnvm supports the OCSSD 1.x and 2.0 specs which were early attempts to produce Open Channel SSDs and never made it into the NVMe spec proper. They have since been superceeded by NVMe enhancements such as ZNS support. Remove the support per the deprecation schedule. Signed-off-by: Christoph Hellwig Link: https://lore.kernel.org/r/20210812132308.38486-1-hch@lst.de Reviewed-by: Matias Bjørling Reviewed-by: Javier González Signed-off-by: Jens Axboe

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: fix lock order in pblk_rb_tear_down_check

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

In pblk_rb_tear_down_check() the spinlock functions are not called in proper order. Fixes: a4bd217 ("lightnvm: physical block device (pblk) target") 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: fix race condition on GC

2019-02-11T15:18:08+00:00

This patch fixes a race condition where a write is mapped to the last sectors of a line. The write is synced to the device but the L2P is not updated yet. When the line is garbage collected before the L2P update is performed, the sectors are ignored by the GC logic and the line is freed before all sectors are moved. When the L2P is finally updated, it contains a mapping to a freed line, subsequent reads of the corresponding LBAs fail. This patch introduces a per line counter specifying the number of sectors that are synced to the device but have not been updated in the L2P. Lines with a counter of greater than zero will not be selected for GC. Signed-off-by: Heiner Litz Reviewed-by: Hans Holmberg Reviewed-by: Javier González Signed-off-by: Matias Bjørling Signed-off-by: Jens Axboe

lightnvm: pblk: prevent stall due to wb threshold

2019-02-11T15:18:08+00:00

In order to respect mw_cuinits, pblk's write buffer maintains a backpointer to protect data not yet persisted; when writing to the write buffer, this backpointer defines a threshold that pblk's rate-limiter enforces. On small PU configurations, the following scenarios might take place: (i) the threshold is larger than the write buffer and (ii) the threshold is smaller than the write buffer, but larger than the maximun allowed split bio - 256KB at this moment (Note that writes are not always split - we only do this when we the size of the buffer is smaller than the buffer). In both cases, pblk's rate-limiter prevents the I/O to be written to the buffer, thus stalling. This patch fixes the original backpointer implementation by considering the threshold both on buffer creation and on the rate-limiters path, when bio_split is triggered (case (ii) above). Fixes: 766c8ceb16fc ("lightnvm: pblk: guarantee that backpointer is respected on writer stall") Signed-off-by: Javier González Reviewed-by: Hans Holmberg 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: fix spelling in comment

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

Signed-off-by: Hua Su Updated description. Signed-off-by: Matias Bjørling Signed-off-by: Jens Axboe

lightnvm: pblk: guarantee that backpointer is respected on writer stall

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

pblk's write buffer must guarantee that it respects the device's constrains for reads (i.e., mw_cunits). This is done by maintaining a backpointer that updates the L2P table as entries wrap up, making them point to the media instead of pointing to the write buffer. This mechanism can race in case that the write thread stalls, as the write pointer will protect the last written entry, thus disregarding the read constrains. This patch adds an extra check on wrap up, making sure that the threshold is respected at all times, preventing new entries to overwrite committed data, also in case of write thread stall. Reported-by: Heiner Litz Signed-off-by: Javier González Reviewed-by: Heiner Litz Signed-off-by: Matias Bjørling Signed-off-by: Jens Axboe

lightnvm: pblk: move ring buffer alloc/free rb init

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

pblk's read/write buffer currently takes a buffer and its size and uses it to create the metadata around it to use it as a ring buffer. This puts the responsibility of allocating/freeing ring buffer memory on the ring buffer user. Instead, move it inside of the ring buffer helpers (pblk-rb.c). This simplifies creation/destruction routines. Signed-off-by: Javier González Signed-off-by: Matias Bjørling Signed-off-by: Jens Axboe

lightnvm: pblk: encapsulate rb pointer operations

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

pblk's read/write buffer is always a power-of-2, thus wrapping up the buffer can be done with a bit mask. Since this is an implementation detail internal to the write buffer, make a helper that hides pointer increment + wrap, and allows to transparently relax this assumption in the future. Signed-off-by: Javier González Signed-off-by: Matias Bjørling Signed-off-by: Jens Axboe