linux-imx

firewire: sbp2: allow WRITE SAME and REPORT SUPPORTED OPERATION CODES

The commits
    3c6bdaeab4fd "[SCSI] Add a report opcode helper"
    5db44863b6eb "[SCSI] sd: Implement support for WRITE SAME"
introduced in-kernel uses of the mentioned commands but cautiously
blacklisted them for any IEEE 1394 (SBP-2/3) targets and some other
transports.

I looked through a range of SBP devices and found that the blacklist
flags can be removed:

The kernel never attempts these commands if the device's INQUIRY
data claim a SCSI revision of less than 0x05.  This is the case with
all SBP devices that I checked, except for three more recent devices
which claimed a revision of 0x05 i.e. conformance with SPC-3 (two
devices based on the OXUF936QSE chip but having different firmwares,
one based on OXUF934DSB.)

I tried "sg_opcodes" from sg3_utils on several older and newer devices
and did not encounter any apparent firmware bugs with it.  All devices
returned Illegal Request/ Invalid command operation code and carried on.
I furthermore tried "sg_write_same -U" on the OXUF934DSB device with the
same result.  Alas I did not have a TRIM enabled SSD available for these
tests.  All of the bridges were correctly identified by the kernel as
"fully provisioned", CD-ROM devices aside.

The kernel won't issue WRITE SAME to fully provisioned devices, nor
would it attempt REPORT SUPPORTED OPERATION CODES or WRITE SAME with
UNMAP bit on devices which do not claim conformance to SPC-3 or later.

Hence let's remove the no_report_opcodes and no_write_same blacklist
flags so that these commands can be used on newer targets with
respective capabilities.  I guess the Linux sbp-target could be such a
target.

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>