Bug 503248

*** Bug 502195 has been marked as a duplicate of this bug. ***

Jamie,

What is the upstream status of new features included?

* Made both WQ and EQ module configurable for FCP multi-queue support

Rob

Rob,

The change that entry refers to was posted to linux-scsi on 25 May as part of this patch:
http://marc.info/?l=linux-scsi&m=124301831918924&w=2

Thanks,
Jamie

This request was evaluated by Red Hat Product Management for inclusion in a Red
Hat Enterprise Linux maintenance release.  Product Management has requested
further review of this request by Red Hat Engineering, for potential
inclusion in a Red Hat Enterprise Linux Update release for currently deployed
products.  This request is not yet committed for inclusion in an Update
release.

Hi Jamie,

A question came up during review of this patch.  Can you answer this?

Rob

> +static uint32_t
> > +lpfc_sli4_scmd_to_wqidx_distr(struct lpfc_hba *phba, struct lpfc_iocbq *piocb)
> > +{
> > +	static uint32_t fcp_qidx;
> > +
> > +	return fcp_qidx++ % phba->cfg_fcp_wq_count;
> > +}

If the number of queues is not a power of two, this would sometimes
return queue index which is not sequential. I don't think it's important,
but we better ask the authors.

Rob,

Thanks for pointing that out - that little function is odd in a couple of ways.  The rollover is fcp_qidx is not handled well (I believe that's what the reviewer was talking about with the non-powers-of-2).  The static count is also shared by multiple HBA ports, which could have side effects.

We'll modify it in the next lpfc update.

- Jamie

Thanks for the info.

Another issue also came up:

> +lpfc_sli4_eq_flush(struct lpfc_hba *phba, struct lpfc_queue *eq) +{ +
> > struct lpfc_eqe *eqe; + + /* walk all the EQ entries and drop on the
> > floor */ + while ((eqe = lpfc_sli4_eq_get(eq))) + ; + + /* Clear and
> > re-arm the EQ */ + lpfc_sli4_eq_release(eq, LPFC_QUEUE_REARM); +} 

There is a value assigned to eqe and then not used.
I don't understand what should this function do, 
can't it happen that it will loop forever ?

in kernel-2.6.18-153.el5
You can download this test kernel from http://people.redhat.com/dzickus/el5

Please do NOT transition this bugzilla state to VERIFIED until our QE team
has sent specific instructions indicating when to do so.  However feel free
to provide a comment indicating that this fix has been verified.

(In reply to comment #12)
> Thanks for the info.
> 
> Another issue also came up:
> 
> > +lpfc_sli4_eq_flush(struct lpfc_hba *phba, struct lpfc_queue *eq) +{ +
> > > struct lpfc_eqe *eqe; + + /* walk all the EQ entries and drop on the
> > > floor */ + while ((eqe = lpfc_sli4_eq_get(eq))) + ; + + /* Clear and
> > > re-arm the EQ */ + lpfc_sli4_eq_release(eq, LPFC_QUEUE_REARM); +} 
> 
> There is a value assigned to eqe and then not used.
> I don't understand what should this function do, 
> can't it happen that it will loop forever ?  

The lpfc_sli4_eq_get() function cycles through a finite circular array, so the loop is bounded.  As the "flush" name implies (or is intended to imply), this function is simply clearing the event queue.  It's called when the link has gone down.

The unused variable and the comment about "drop on the floor" was intended to show that the entries are intentionally not being processed here.

Thanks, Jamie

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Verified EEH recovery functions as expected in RHEL5.4 snapshot 1 with lpfc driver version 8.2.0.46 on Power PC platforms.

Verified that the patch is included in kernel-2.6.18-160.el5

Emulex, do you expect to test and report back test results for this item?

Verified by Emulex.

Laurie

Thanks. Please make sure to check that all additional emulex bugs are updated after verification.

An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on therefore solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.

http://rhn.redhat.com/errata/RHSA-2009-1243.html

The needinfo request[s] on this closed bug have been removed as they have been unresolved for 1000 days