hunk by hunk:
- CHECK_CONDITION is what happens to cmnd->status >> 1
or after status_byte() macro. But here it is used
directly on status which means 0x1 which is an undefined
bit in the standard. And is a status that will never
return from a target.
- in busfree_run at the DONE_SC phase we have 3 distinct
operation:
1-if(DONE_SC->SCp.phase & check_condition)
The REQUEST_SENSE command return.
- Restore original command
- Than continue to operation 3.
2-if(DONE_SC->SCp.Status==SAM_STAT_CHECK_CONDITION)
A regular command returned with a status.
- Internally re-Q a REQUEST_SENSE.
- Do not do operation 3.
3-
- Complete the command and return it to scsi-ml
So the 0x2 in both these operations (1,2) means the scsi
check-condition status, hence SAM_STAT_CHECK_CONDITION
- Here the code asks about !(DONE_SC->SCp.Status & not_issued)
but "not_issued" is an enum belonging to the "phase" member
and not to the Status returned from target. The reason this
works is because not_issued==1 and Also CHECK_CONDITION==1
(remember from hunk 1). So actually the code was asking
!(DONE_SC->SCp.Status & CHECK_CONDITION). Which means
"Has the status been read from target yet?"
Staus is read at status_run(). "not_issued" is
cleared in seldo_run() which is usually earlier than
status_run().
So this patch does nothing as far as assembly is concerned
but it does let the reader understand what is going on.
Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
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