Eliminate duplicate boilerplate code for simple modules that contain
a single DM target driver without any additional setup code.

Add a new module_dm() macro, which replaces the module_init() and
module_exit() with template functions that call dm_register_target()
and dm_unregister_target() respectively.

Signed-off-by: Yangtao Li <frank.li@vivo.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>

Simplifies each DM target's init method by making dm_register_target()
responsible for its error reporting (on behalf of targets).

Signed-off-by: Yangtao Li <frank.li@vivo.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>

Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>

'GPL-2.0-only' is used instead of 'GPL-2.0' because SPDX has
deprecated its use.

Suggested-by: John Wiele <jwiele@redhat.com>
Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>

Remove needless factoring and remap bi_sector regardless of
bio_sectors() being non-zero.

Signed-off-by: Mike Snitzer <snitzer@kernel.org>

Remove the from_wq argument from dm_sumbit_bio_remap(). Eliminates the
need for dm_sumbit_bio_remap() callers to know whether they are
calling for a workqueue or from the original dm_submit_bio().

Add map_task to dm_io struct, record the map_task in alloc_io and
clear it after all target ->map() calls have completed. Update
dm_sumbit_bio_remap to check if 'current' matches io->map_task rather
than rely on passed 'from_rq' argument.

This change really simplifies the chore of porting each DM target to
using dm_sumbit_bio_remap() because there is no longer the risk of
programming error by not completely knowing all the different contexts
a particular method that calls dm_sumbit_bio_remap() might be used in.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>

Reviewed-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

For device mapper targets to take advantage of IMA's measurement
capabilities, the status functions for the individual targets need to be
updated to handle the status_type_t case for value STATUSTYPE_IMA.

Update status functions for the following target types, to log their
respective attributes to be measured using IMA.
 01. cache
 02. crypt
 03. integrity
 04. linear
 05. mirror
 06. multipath
 07. raid
 08. snapshot
 09. striped
 10. verity

For rest of the targets, handle the STATUSTYPE_IMA case by setting the
measurement buffer to NULL.

For IMA to measure the data on a given system, the IMA policy on the
system needs to be updated to have the following line, and the system
needs to be restarted for the measurements to take effect.

/etc/ima/ima-policy
 measure func=CRITICAL_DATA label=device-mapper template=ima-buf

The measurements will be reflected in the IMA logs, which are located at:

/sys/kernel/security/integrity/ima/ascii_runtime_measurements
/sys/kernel/security/integrity/ima/binary_runtime_measurements

These IMA logs can later be consumed by various attestation clients
running on the system, and send them to external services for attesting
the system.

The DM target data measured by IMA subsystem can alternatively
be queried from userspace by setting DM_IMA_MEASUREMENT_FLAG with
DM_TABLE_STATUS_CMD.

Signed-off-by: Tushar Sugandhi <tusharsu@linux.microsoft.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

generic_make_request has always been very confusingly misnamed, so rename
it to submit_bio_noacct to make it clear that it is submit_bio minus
accounting and a few checks.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

When the target line contains an invalid device, delay_ctr() will call
delay_dtr() with NULL workqueue.  Attempting to destroy the NULL
workqueue causes a crash.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Mike Snitzer <snitzer@redhat.com>