Hi,

There was a recent commit in mainline for the scsi devices which do not
respond properly to medium access command:

commit    18a4d0a22ed6c54b67af7718c305cd010f09ddf8

[SCSI] Handle disk devices which can not process medium access commands
We have experienced several devices which fail in a fashion we do not
currently handle gracefully in SCSI. After a failure these devices will
respond to the SCSI primary command set (INQUIRY, TEST UNIT READY, etc.)
but any command accessing the storage medium will time out.

I came across a USB drive which showed similar problem and what I see is
usb storage is still not able to cope with such devices properly.

The control flow downwards is like:
scsi_times_out --> Setting cmd->result as DID_TIME_OUT
scsi_error_handler
scsi_unjam_host
scsi_eh_abort_cmds
command_abort    (sets US_FLIDX_TIMED_OUT for us->dflags
                                    calls stop_transport,
                                    and waits for)    usb_stor_control_thread (which is waiting for
                                                                     transport call to return inside
                                                                     usb_stor_invoke_transport)
                                                                     both usb_stor_control_thread and
                                                                     usb_stor_invoke_transport
                                                      check for us->dflags timed_out bit and
                                                       set the result as DID_ABORT
                                                       and signal completion for command_abort
                                                       to complete
......
sd_eh_action
checks for cmd->result and finds out that it's DID_ABORT rather than
DID_TIME_OUT.

This patch updates the command result to be TIME_OUT explicitly before
returning from command_abort in scsiglue.c.

I would like to know if this patch can work out for such USB Storage
devices? What would be the better way to do the same?


Regards,
Vishal Annapurve


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