On 08/19/05 01:40, Tejun Heo wrote:

  I genearally agree that the events are somewhat standard for block 
devices but IMHO SCSI EH also has fair amount SCSI-specific assumptions 
and ATA is a bit too different from SCSI to fit cleanly into it.  For 
example, when handling NCQ errors, the whole task set is aborted and the 
status is retrieved with read log page.  This can be worked around in 
one of the hooks and emulate SCSI behavior, but it just doesn't really 
fit well.  And I think that recovering via translation layer is a bit 
too much translation.

  So, my thought is that SCSI EH assumptions are a bit too specific to 
be used as standard for block devices.

Ok, so everyone seems to agree on this.
 

  It's true that we must do SCSI specific tasks inside libata if we use 
eh_strategy_handler but I don't think switching to fine-grained EH will 
reduce the amount of SCSI-specific things inside libata.  I think as 
long as we can insulate LLDD's from SCSI layer, either way should be 
okay later.

True, this is the goal.  Separation between device management
and how that device got to you, is the future and should be the
a goal.

  I agree that being the only user does incur difficulties, but my very 
subjective feeling is that the original libata EH implementation was 
just a bit too fragile to start with.  eg. not grabbing host lock on EH 
entrance causing command completion vs. EH handling race and handling 
errors in several different ways.

  Heh... Maybe I'm just reluctant to let go of my patches.  Anyways, 
I'll now stand down and see how things go and try to help.

Please don't do that.  One thing everyone in the Linux community knows
is that Linux-SCSI needs fresh minds and fresh ideas.  Especially from
knowlegable folks in the storage protocols and standards.

	Luben