Re: [PATCH v3 1/2] scsi: Handle Unit Attention when issuing SCSI command

[James Bottomley <jejb@linux.vnet.ibm.com>]

On Tue, 2016-10-25 at 23:18 +0000, Bart Van Assche wrote:
> On Tue, 2016-10-25 at 15:23 -0700, James Bottomley wrote:
> > Because scsi_execute uses REQ_BLOCK_PC which is completed before 
> > you get to that code.
> 
> Hello James,
> 
> Do you perhaps mean that scsi_io_completion() returns early for
> REQ_TYPE_BLOCK_PC requests? Can you clarify this further?

I'm not sure how much simpler I can make it.  How about: the first if
block gives a non zero value in error causing scsi_end_request to
signal an immediate return?

> Anyway, currently the following functions interpret the SCSI sense
> buffer:
> * scsi_io_completion() in scsi_lib.c.
> * scsi_mode_sense() in scsi_lib.c.
> * scsi_test_unit_ready_flags() in scsi_lib.c.
> * scsi_probe_lun() in scsi_scan.c.
> * scsi_report_lun_scan() in scsi_scan.c.
> * ioctl_internal_command() in scsi_ioctl.c.
> * sg_rq_end_io() in sg.c.
> * scsi_check_sense() in scsi_error.c.
> * spi_execute() in scsi_transport_spi.c.
> 
> Are you sure we should add sense code interpretation code in a tenth
> function in the SCSI core?

In the absence of a better proposal, yes.  I originally looked into
better BLOCK_PC error handling in scsi_io_completion, but that has some
knock on problems, so it seems best to leave it alone.

James