Quoting James Bottomley <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx>:
On Mon, 2013-04-15 at 16:55 -0500, Brian King wrote:
On 04/15/2013 03:45 PM, James Bottomley wrote:
> On Mon, 2013-04-15 at 13:39 -0500, wenxiong@xxxxxxxxxxxxxxxxxx wrote:
>> In scsi_send_eh_cmnd(), this fix will check the return code of
queuecomamnd
>> when sending commands and retry for a bit if the driver returns a
>> busy response.
>
> This is already handled by the timeout, I think. If a driver
> continuously returns MLQUEUE BUSY, then we'll fail the request after the
> timeout on the command expires.
If we get a timeout in scsi_send_eh_cmnd we call scsi_abort_eh_cmnd. If the
abort works, we return FAILED out of scsi_send_eh_cmnd, which results in
no retry being performed, since scsi_eh_tur only retries once and
only if NEEDS_RETRY is returned. Or am I missing something?
Sorry, I'm not being clear. It comes with being at a conference. What
I mean is that if you do this, the criterion for success or faiure
should be the amount of time left not the number of retries. This is
what the non-eh submission path also does for retries of events that
don't count against the retry limit ... so something like this patch
(uncompiled and untested #include stddisclaimer.h)
James
Hi James,
The failing case for us is: Doesn't matter what timeout value we set in
wait_for_completion_timeout(), it always returns with timeleft = 0.
For example, if I set timeout = 50 secs, wait_for_completion_timeout()
always returns with timeleft =0(even adapter is already in good shape in
20 secs). We never gets a chance to call into if (timeleft) leg.
My understanding is: if shost->host->queuecommand() failed with MLQUEUE busy
response at the first time, wait_for_completion_timeout() always wakes
up by expired.
Here is log when I enabled scsi log:
Apr 15 18:44:35 ltcsatiocp5 kernel: scsi_send_eh_cmnd: scmd:
c0000000f88bc980, timeleft: 0
I applied your patch. Because timeleft is always zero, never got a
chance to call into
if(timeleft) { leg.
Thanks,
Wendy
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