[PATCH v4 0/4] scsi: target: COMPARE AND WRITE miscompare sense

[David Disseldorp <ddiss@suse.de>]

This patchset adds missing functionality to return the offset of
non-matching read/compare data in the sense INFORMATION field on
COMPARE AND WRITE miscompare.

The functionality can be tested using the libiscsi
CompareAndWrite.MiscompareSense test proposed via:
  https://github.com/sahlberg/libiscsi/pull/344

Changes since v3:
- (4/4) optimize for equality, as suggested by Doug
  + perform byte-by-byte offset check only after memcmp() failure
  + drop Mike's RB tag due to this rework

Changes since v2:
- perform bad_sector->sense_info rename in overlooked ib_isert
- drop scatterlist change queued via Jens' tree
- add Mike's reviewed-by tag
- rebase against Martin's 5.11/scsi-queue branch

Changes since v1:
- drop unnecessary WARN_ON()
- fix two checkpatch warnings
- drop single-use nlbas variable
- avoid compare_len recalculation

Cheers, David

 drivers/infiniband/ulp/isert/ib_isert.c |   4 +-
 drivers/target/target_core_sbc.c        | 138 ++++++++++++++----------
 drivers/target/target_core_transport.c  |  33 +++---
 include/target/target_core_base.h       |   2 +-
 4 files changed, 104 insertions(+), 73 deletions(-)