linux-toradex.git/drivers/lightnvm, branch v4.20-rc3

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: consider max hw sectors supported for max_write_pgs

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

When do GC, the number of read/write sectors are determined
by max_write_pgs(see gc_rq preparation in pblk_gc_line_prepare_ws).

Due to max_write_pgs doesn't consider max hw sectors
supported by nvme controller(128K), which leads to GC
tries to read 64 * 4K in one command, and see below error
caused by pblk_bio_map_addr in function pblk_submit_read_gc.

[ 2923.005376] pblk: could not add page to bio
[ 2923.005377] pblk: could not allocate GC bio (18446744073709551604)

Signed-off-by: Zhoujie Wu 
Reviewed-by: Javier González 
Signed-off-by: Matias Bjørling 
Signed-off-by: Jens Axboe

lightnvm: pblk: fix error handling of pblk_lines_init()

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

In the too many bad blocks error handling case, we should release all
the allocated resources, otherwise it will cause memory leak.

Fixes: 2deeefc02dff ("lightnvm: pblk: fail gracefully on line alloc. failure")
Signed-off-by: Wei Yongjun 
Reviewed-by: Hans Holmberg 
Signed-off-by: Matias Bjørling 
Signed-off-by: Jens Axboe

lightnvm: pblk: guarantee mw_cunits on read buffer

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

OCSSD 2.0 defines the amount of data that the host must buffer per chunk
to guarantee reads through the geometry field mw_cunits. This value is
the base that pblk uses to determine the size of its read buffer.
Currently, this size is set to be the closes power-of-2 to mw_cunits
times the number of parallel units available to the pblk instance for
each open line (currently one). When an entry (4KB) is put in the
buffer, the L2P table points to it. As the buffer wraps up, the L2P is
updated to point to addresses on the device, thus guaranteeing mw_cunits
at a chunk level.

However, given that pblk cannot write to the device under ws_min
(normally ws_opt), there might be a window in which the buffer starts
wrapping up and updating L2P entries before the mw_cunits value in a
chunk has been surpassed.

In order not to violate the mw_cunits constrain in this case, account
for ws_opt on the read buffer creation.

Signed-off-by: Javier González 
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

lightnvm: pblk: remove unused function

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

Removed unused function in pblk-rb.c

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

lightnvm: pblk: fix race on sysfs line state

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

pblk exposes a sysfs interface that represents its internal state. Part
of this state is the map bitmap for the current open line, which should
be protected by the line lock to avoid a race when freeing the line
metadata. Currently, it is not.

This patch makes sure that the line state is consistent and NULL
bitmap pointers are not dereferenced.

Signed-off-by: Javier González 
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

lightnvm: pblk: recover open lines on 2.0 devices

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

In the OCSSD 2.0 spec, each chunk reports its write pointer. This means
that pblk does not need to scan open lines to find the write pointer,
but instead, it can retrieve it directly (and verify it).

This patch uses the write pointer on open lines to (i) recover the line
up until the last written lba and (ii) reconstruct the map bitmap and
rest of line metadata so that the line can be used for new data.

Since the 1.2 path in lightnvm core has been re-implemented to populate
the chunk structure and thus recover the write pointer on
initialization, this patch removes 1.2 specific recovery, as the 2.0
path can be reused.

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