Hello, Luben.
Luben Tuikov wrote:
--- Tejun Heo <htejun@xxxxxxxxx> wrote:
This patch implements scsi_eh_schedule_cmd() which provides a way to
directly invoke SCSI EH from drivers implementing
->eh_strategy_handler. Combined with scsi_eh_flush_done_q(), this
gives such drivers complete control over when and how to invoke EH and
handle failed commands.
Hi Tejun,
I sent an almost identical patch, albeit much more general, see this:
http://marc.theaimsgroup.com/?l=linux-scsi&m=113833937421677&w=2
Here is the core of it:
--start-quote--
This function requests that SCSI Core start recovery for the
command by deleting the timer and adding the command to the eh
queue. It can be called by either LLDDs or SCSI Core. LLDDs who
implement their own error recovery MAY ignore the timeout event if
they generated scsi_req_abort_cmd.
void scsi_req_abort_cmd(struct scsi_cmnd *cmd)
{
if (!scsi_delete_timer(cmd))
return;
scsi_times_out(cmd);
}
--end-quote---
To have a consistent and complete error recovery solution, given
the current SCSI Core infrastructure, as is requred for your SATA effort,
and other (protocol) work, this is what one needs to implement:
1. eh_timed_out(),
2. eh_strategy_handler(),
3. scsi_req_abort_cmd() (as shown above), and finally,
4. scsi_req_dev_reset().
I keep those in my own git trees. (Had 3 been accepted, I would've sent 4.)
Hmmm... Is scsi_req_dev_reset() similar to scsi_eh_schedule_host()? ie.
Does it request EH without scmd? If so, can you post the patch? I'm
okay with anything that works. All that I need are...
* Non-hackish way to invoke EH on scmd from drivers implementing its own
EH. DID_TIME_OUT solution James talked about in the thread isn't
enough. It needs to invoke EH whatever the command is.
* Invoking EH without scmd.
IMHO, it's better to allow such driver to tap directly into EH rather
than making it pass through normal SCSI EH decision making process
(scsi_device_disposition). It's much simpler that way.
James, can you tell us what you're thinking about this matter?
Thanks.
--
tejun
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