Re: [Qemu-devel] [PATCH 03/11] pseries: Clean up hash page table allocation error handling

[David Gibson <david@gibson.dropbear.id.au>]

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On Fri, Dec 11, 2015 at 02:10:40PM +0530, Bharata B Rao wrote:
> On Fri, Dec 11, 2015 at 5:41 AM, David Gibson
> <david@gibson.dropbear.id.au> wrote:
> > The spapr_alloc_htab() and spapr_reset_htab() functions currently handle
> > all errors with error_setg(&error_abort, ...).  That's correct for
> > spapr_reset_htab() - if anything goes wrong there, there's really nothing
> > we can do about it.  For spapr_alloc_htab() &error_fatal would make more
> > sense, since it occurs during initialization.
> >
> > But in any case the callers are really better placed to decide on the error
> > handling.  So, instead make the functions use the error propagation
> > infrastructure.
> >
> > While we're at it improve the messages themselves a bit, and clean up the
> > indentation a little.
> >
> > Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
> > ---
> >  hw/ppc/spapr.c | 26 ++++++++++++++++++--------
> >  1 file changed, 18 insertions(+), 8 deletions(-)
> >
> > diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> > index 91396cc..85474ee 100644
> > --- a/hw/ppc/spapr.c
> > +++ b/hw/ppc/spapr.c
> > @@ -1015,7 +1015,7 @@ static void emulate_spapr_hypercall(PowerPCCPU *cpu)
> >  #define CLEAN_HPTE(_hpte)  ((*(uint64_t *)(_hpte)) &= tswap64(~HPTE64_V_HPTE_DIRTY))
> >  #define DIRTY_HPTE(_hpte)  ((*(uint64_t *)(_hpte)) |= tswap64(HPTE64_V_HPTE_DIRTY))
> >
> > -static void spapr_alloc_htab(sPAPRMachineState *spapr)
> > +static void spapr_alloc_htab(sPAPRMachineState *spapr, Error **errp)
> >  {
> >      long shift;
> >      int index;
> > @@ -1030,7 +1030,9 @@ static void spapr_alloc_htab(sPAPRMachineState *spapr)
> >           * For HV KVM, host kernel will return -ENOMEM when requested
> >           * HTAB size can't be allocated.
> >           */
> > -        error_setg(&error_abort, "Failed to allocate HTAB of requested size, try with smaller maxmem");
> > +        error_setg(errp,
> > +            "Error allocating KVM hash page table, try smaller maxmem: %s",
> > +            strerror(-shift));
> 
> Do you want to explicitly "return" from here and other places in this
> patch like you do in 4/11 to improve readability ?

Given we still need the if (shift > 0), I don't think it really makes
any difference to readability.

-- 
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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