Re: [Qemu-devel] [PATCH for-4.0 v9 10/16] qemu_thread: supplement error handling for h_resize_hpt_prepare

[David Gibson]

On Thu, Jan 03, 2019 at 09:41:49PM +0800, Fei Li wrote:
> 
> 在 2019/1/3 上午11:43, David Gibson 写道:
> > On Wed, Jan 02, 2019 at 02:44:17PM +0800, 李菲 wrote:
> > > 在 2019/1/2 上午10:36, David Gibson 写道:
> > > > On Tue, Dec 25, 2018 at 10:04:43PM +0800, Fei Li wrote:
> > > > > Add a local_err to hold the error, and return the corresponding
> > > > > error code to replace the temporary &error_abort.
> > > > > 
> > > > > Cc: Markus Armbruster <address@hidden>
> > > > > Cc: David Gibson <address@hidden>
> > > > > Signed-off-by: Fei Li <address@hidden>
> > > > This looks like a good change, but it no longer applies due to a
> > > > change in the qemu_thread_create() signature.
> > > Sorry that I am not sure whether I understand. Do you mean using
> > > &error_abort is more suitable for this handling, rather than report
> > > the &local_err & return a failure reason?
> > No, I just mean that context has been altered by a global change and
> > the patch will need to be fixed up to cope with that.
> 
> Just to be clearer: does the "global change" mean the "[patch 06/16]
> qemu_thread: Make qemu_thread_create() handle errors properly", or another
> patch not in this patch series?
> 
> If it means the [patch 06/16], I want to explain more: the 06/16 handles all
> qemu_thread_create() by passing &error_abort as the parameter, and the
> following patches are to improve on the &error_abort for callers who can
> handle more properly. E.g. if qemu_thread_create() fails in
> h_resize_hpt_prepare(),
> I think reporting the &local_err & returning the failure reason is more
> proper
> than just abort() inside qemu_thread_create() when calls error_setg_errno().
> 
> In other words, this patch is actually written to apply to patch 06. And I
> have
> no clue where it needs to be fixed up. Please correct me if I understand
> wrong.
> 
> 
> Have a nice day, thanks :)

Ah, sorry.  Since I was only CCed on this patch, not the rest of the
series, I assumed it was independent and didn't think to check the
earlier patches of the series.

So, yes, I think the global change I'm referring to is 6/16, which I
didn't have, so that explains the problem.

In that case it's probably best if this goes in via the same tree the
rest of the series is going to.  So, with the H_HARDWARE change made:

Acked-by: David Gibson <address@hidden>


> Fei
> 
> 
> > 
> > > > > ---
> > > > >    hw/ppc/spapr_hcall.c | 12 ++++++++----
> > > > >    1 file changed, 8 insertions(+), 4 deletions(-)
> > > > > 
> > > > > diff --git a/hw/ppc/spapr_hcall.c b/hw/ppc/spapr_hcall.c
> > > > > index 5bc2cf4540..7c16ade04a 100644
> > > > > --- a/hw/ppc/spapr_hcall.c
> > > > > +++ b/hw/ppc/spapr_hcall.c
> > > > > @@ -478,6 +478,7 @@ static target_ulong 
> > > > > h_resize_hpt_prepare(PowerPCCPU *cpu,
> > > > >        sPAPRPendingHPT *pending = spapr->pending_hpt;
> > > > >        uint64_t current_ram_size;
> > > > >        int rc;
> > > > > +    Error *local_err = NULL;
> > > > >        if (spapr->resize_hpt == SPAPR_RESIZE_HPT_DISABLED) {
> > > > >            return H_AUTHORITY;
> > > > > @@ -538,10 +539,13 @@ static target_ulong 
> > > > > h_resize_hpt_prepare(PowerPCCPU *cpu,
> > > > >        pending->shift = shift;
> > > > >        pending->ret = H_HARDWARE;
> > > > > -    /* TODO: let the further caller handle the error instead of 
> > > > > abort() here */
> > > > > -    qemu_thread_create(&pending->thread, "sPAPR HPT prepare",
> > > > > -                       hpt_prepare_thread, pending,
> > > > > -                       QEMU_THREAD_DETACHED, &error_abort);
> > > > > +    if (!qemu_thread_create(&pending->thread, "sPAPR HPT prepare",
> > > > > +                            hpt_prepare_thread, pending,
> > > > > +                            QEMU_THREAD_DETACHED, &local_err)) {
> > > > > +        error_reportf_err(local_err, "failed to create 
> > > > > hpt_prepare_thread: ");
> > > > > +        g_free(pending);
> > > > > +        return H_RESOURCE;
> > > > I also think H_HARDWARE would be a better choice here.  Although the
> > > > failure is due to a resource constraint, it's not because the guest
> > > > asked for too much, just because the host is in dire straits.  From
> > > > the guest's point of view it's basically a hardware failure.
> > > Ok, thanks. Will use H_HARDWARE instead.
> > > 
> > > Have a nice day, thanks for the review. :)
> > > Fei
> > > > > +    }
> > > > >        spapr->pending_hpt = pending;
> 

-- 
David Gibson                    | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au  | minimalist, thank you.  NOT _the_ _other_
                                | _way_ _around_!
http://www.ozlabs.org/~dgibson

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