According to FCP-4 there are several possibilities for target to react on
incorrect data length field value in CDB:
a) process the command normally except that data beyond the FCP_DL count
shall not be requested or transferred;
b) transfer no data and return CHECK CONDITION status with the sense key
set to ILLEGAL REQUEST and the additional sense code set to
INVALID FIELD IN COMMAND INFORMATION UNIT;
Add check to support the second one and accept no data write.
Looking at test_write10_residuals.c, test_write12_residuals.c and
test_write16_residuals.c tests the similarity of the testing scenario
can be found. There are several EDTL and SPDTL combinations which are
the same for different length write command tests. They form the core
of testing scenario of these commands. There aren't so much differences
in the way of testing these combinations itself either. It is possible
to move the main parameters describing the testing scenario into a
separate structure and move the scenario itself into a separate function.
It will increase the readability and reduce the duplicate code of these tests.
