linux-toradex.git/drivers/block/null_blk_main.c, branch v4.20

block: Introduce blk_revalidate_disk_zones()

2018-10-25T17:17:40+00:00

Drivers exposing zoned block devices have to initialize and maintain
correctness (i.e. revalidate) of the device zone bitmaps attached to
the device request queue (seq_zones_bitmap and seq_zones_wlock).

To simplify coding this, introduce a generic helper function
blk_revalidate_disk_zones() suitable for most (and likely all) cases.
This new function always update the seq_zones_bitmap and seq_zones_wlock
bitmaps as well as the queue nr_zones field when called for a disk
using a request based queue. For a disk using a BIO based queue, only
the number of zones is updated since these queues do not have
schedulers and so do not need the zone bitmaps.

With this change, the zone bitmap initialization code in sd_zbc.c can be
replaced with a call to this function in sd_zbc_read_zones(), which is
called from the disk revalidate block operation method.

A call to blk_revalidate_disk_zones() is also added to the null_blk
driver for devices created with the zoned mode enabled.

Finally, to ensure that zoned devices created with dm-linear or
dm-flakey expose the correct number of zones through sysfs, a call to
blk_revalidate_disk_zones() is added to dm_table_set_restrictions().

The zone bitmaps allocated and initialized with
blk_revalidate_disk_zones() are freed automatically from
__blk_release_queue() using the block internal function
blk_queue_free_zone_bitmaps().

Reviewed-by: Hannes Reinecke 
Reviewed-by: Christoph Hellwig 
Reviewed-by: Martin K. Petersen 
Reviewed-by: Mike Snitzer 
Signed-off-by: Damien Le Moal 
Signed-off-by: Jens Axboe

block: add a report_zones method

2018-10-25T17:17:40+00:00

Dispatching a report zones command through the request queue is a major
pain due to the command reply payload rewriting necessary. Given that
blkdev_report_zones() is executing everything synchronously, implement
report zones as a block device file operation instead, allowing major
simplification of the code in many places.

sd, null-blk, dm-linear and dm-flakey being the only block device
drivers supporting exposing zoned block devices, these drivers are
modified to provide the device side implementation of the
report_zones() block device file operation.

For device mappers, a new report_zones() target type operation is
defined so that the upper block layer calls blkdev_report_zones() can
be propagated down to the underlying devices of the dm targets.
Implementation for this new operation is added to the dm-linear and
dm-flakey targets.

Reviewed-by: Hannes Reinecke 
Signed-off-by: Christoph Hellwig 
[Damien]
* Changed method block_device argument to gendisk
* Various bug fixes and improvements
* Added support for null_blk, dm-linear and dm-flakey.
Reviewed-by: Martin K. Petersen 
Reviewed-by: Mike Snitzer 
Signed-off-by: Damien Le Moal 
Signed-off-by: Jens Axboe

null_blk: remove set but not used variable 'q'

2018-10-16T02:02:59+00:00

Fixes gcc '-Wunused-but-set-variable' warning:

drivers/block/null_blk_main.c: In function 'end_cmd':
drivers/block/null_blk_main.c:609:24: warning:
 variable 'q' set but not used [-Wunused-but-set-variable]

It not used any more after commit
e50b1e327aeb ("null_blk: remove legacy IO path")

Signed-off-by: YueHaibing 
Signed-off-by: Jens Axboe

null_blk: remove legacy IO path

2018-10-14T18:49:31+00:00

We're planning on removing this code completely, kill the old
path.

Signed-off-by: Jens Axboe

null_blk: fix zoned support for non-rq based operation

2018-09-13T00:21:11+00:00

The supported added for zones in null_blk seem to assume that only rq
based operation is possible. But this depends on the queue_mode setting,
if this is set to 0, then cmd->bio is what we need to be operating on.
Right now any attempt to load null_blk with queue_mode=0 will
insta-crash, since cmd->rq is NULL and null_handle_cmd() assumes it to
always be set.

Make the zoned code deal with bio's instead, or pass in the
appropriate sector/nr_sectors instead.

Fixes: ca4b2a011948 ("null_blk: add zone support")
Tested-by: Omar Sandoval 
Signed-off-by: Jens Axboe

null_blk: add lock drop/acquire annotation

2018-08-09T20:22:41+00:00

sparse complains:

drivers/block/null_blk_main.c:816:24: sparse: context imbalance in 'null_insert_page' - unexpected unlock

Fix it by adding the necessary annotations to the function.

Signed-off-by: Jens Axboe

block: Rename the null_blk_mod kernel module back into null_blk

2018-07-24T15:54:36+00:00

Commit ca4b2a011948 ("null_blk: add zone support") breaks several
blktests scripts because it renamed the null_blk kernel module into
null_blk_mod. Hence rename null_blk_mod back into null_blk.

Fixes: ca4b2a011948 ("null_blk: add zone support")
Signed-off-by: Bart Van Assche 
Cc: Matias Bjorling 
Cc: Christoph Hellwig 
Cc: Ming Lei 
Cc: Damien Le Moal 
Signed-off-by: Jens Axboe