[Skiboot] [PATCH v2 12/52] libflash/ipmi-hiomap: Overhaul event handling

[Andrew Jeffery]

On Tue, 26 Feb 2019, at 02:55, Vasant Hegde wrote:
> On 02/21/2019 11:58 AM, Andrew Jeffery wrote:
> > Reworking the event handling was inspired by a bug report by Vasant
> > where the host would get wedged on multiple flash access attempts in the
> > face of a persistent error state on the BMC-side. The cause of this bug
> > was the early-exit based on ctx->update, which erronously assumed that
> > all events had been completely handled in prior calls to
> > ipmi_hiomap_handle_events(). This is not true if e.g.
> > HIOMAP_E_DAEMON_READY is clear in the prior calls.
> > 
> > Regardless, there were other correctness and efficiency problems with
> > the handling strategy:
> > 
> > * Ack-able event state was not restored in the face of errors in the
> >    process of re-establishing protocol state
> > 
> > * It forced needless window restoration with respect to the context in
> >    which ipmi_hiomap_handle_events() was called.
> > 
> > * Tests for HIOMAP_E_DAEMON_READY and HIOMAP_E_FLASH_LOST were redundant
> >    with the overhauled error handling introduced in the previous patch
> > 
> > Fix all of the above issues and add comments to explain the event
> > handling flow.
> > 
> > Tests for correctness follow later in the series.
> > 
> > Cc: stable
> > Cc: Vasant Hegde <hegdevasant at linux.vnet.ibm.com>
> 
> Looks like your mail client did not like me.  I was not CCed.

I ended up using --supress-cc=body with git send-email to avoid headaches
from adding Cc: stable.

I was intending to ping you to point you to the patch but it didn't quite happen
before Stewart merged the series.

> 
> 
> > Signed-off-by: Andrew Jeffery <andrew at aj.id.au>
> 
> I have reviewed/tested this patch. Looks good. This will help to reduce the the 
> hard lockup issue.

Great! Thanks for taking a look.

Andrew

> 
> -Vasant
> 
> 
>