Re: [PATCH 17/20] spapr: Remove unused return value in claim path

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

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On Thu, Sep 26, 2019 at 10:36:02AM +0200, Greg Kurz wrote:
> On Wed, 25 Sep 2019 16:45:31 +1000
> David Gibson <david@gibson.dropbear.id.au> wrote:
> 
> > spapr_irq_claim() and the hooks it is based on return an integer error code
> > as well as taking an Error ** parameter.  But none of the callers check the
> > integer, so we can remove it and just use the richer Error **.
> > 
> > Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
> > ---
> 
> FYI, the very same topic of using the return value versus Error ** to
> check errors was discussed recently in this thread:
> 
> https://lists.gnu.org/archive/html/qemu-devel/2019-09/msg04197.html
> 
> I tend to agree with Daniel (Cc'd) at first thought, but I don't have a strong
> opinion about this yet. It is mostly to inform you that people are currently
> discussing/working on it.

So, I made this change mostly because redundant encodings give me an
itch.  But having read that post and then experimented a bit, I found
the approach he proposes does cut down a noticeable amount of
boilerplate.

So I think I'll move towards that approach and drop this patch.

> 
> >  hw/ppc/spapr_irq.c         | 32 +++++++++++++-------------------
> >  include/hw/ppc/spapr_irq.h |  4 ++--
> >  2 files changed, 15 insertions(+), 21 deletions(-)
> > 
> > diff --git a/hw/ppc/spapr_irq.c b/hw/ppc/spapr_irq.c
> > index 261d66ba17..2673a90604 100644
> > --- a/hw/ppc/spapr_irq.c
> > +++ b/hw/ppc/spapr_irq.c
> > @@ -112,8 +112,8 @@ static void spapr_irq_init_xics(SpaprMachineState *spapr, Error **errp)
> >      spapr->ics = ICS_SPAPR(obj);
> >  }
> >  
> > -static int spapr_irq_claim_xics(SpaprMachineState *spapr, int irq, bool lsi,
> > -                                Error **errp)
> > +static void spapr_irq_claim_xics(SpaprMachineState *spapr, int irq, bool lsi,
> > +                                 Error **errp)
> >  {
> >      ICSState *ics = spapr->ics;
> >  
> > @@ -122,11 +122,10 @@ static int spapr_irq_claim_xics(SpaprMachineState *spapr, int irq, bool lsi,
> >  
> >      if (!ics_irq_free(ics, irq - ics->offset)) {
> >          error_setg(errp, "IRQ %d is not free", irq);
> > -        return -1;
> > +        return;
> >      }
> >  
> >      ics_set_irq_type(ics, irq - ics->offset, lsi);
> > -    return 0;
> >  }
> >  
> >  static void spapr_irq_free_xics(SpaprMachineState *spapr, int irq)
> > @@ -252,14 +251,12 @@ static void spapr_irq_init_xive(SpaprMachineState *spapr, Error **errp)
> >      spapr_xive_hcall_init(spapr);
> >  }
> >  
> > -static int spapr_irq_claim_xive(SpaprMachineState *spapr, int irq, bool lsi,
> > -                                Error **errp)
> > +static void spapr_irq_claim_xive(SpaprMachineState *spapr, int irq, bool lsi,
> > +                                 Error **errp)
> >  {
> >      if (!spapr_xive_irq_claim(spapr->xive, irq, lsi)) {
> >          error_setg(errp, "IRQ %d is invalid", irq);
> > -        return -1;
> >      }
> > -    return 0;
> >  }
> >  
> >  static void spapr_irq_free_xive(SpaprMachineState *spapr, int irq)
> > @@ -406,25 +403,22 @@ static void spapr_irq_init_dual(SpaprMachineState *spapr, Error **errp)
> >      }
> >  }
> >  
> > -static int spapr_irq_claim_dual(SpaprMachineState *spapr, int irq, bool lsi,
> > -                                Error **errp)
> > +static void spapr_irq_claim_dual(SpaprMachineState *spapr, int irq, bool lsi,
> > +                                 Error **errp)
> >  {
> >      Error *local_err = NULL;
> > -    int ret;
> >  
> > -    ret = spapr_irq_xics.claim(spapr, irq, lsi, &local_err);
> > +    spapr_irq_xics.claim(spapr, irq, lsi, &local_err);
> >      if (local_err) {
> >          error_propagate(errp, local_err);
> > -        return ret;
> > +        return;
> >      }
> >  
> > -    ret = spapr_irq_xive.claim(spapr, irq, lsi, &local_err);
> > +    spapr_irq_xive.claim(spapr, irq, lsi, &local_err);
> >      if (local_err) {
> >          error_propagate(errp, local_err);
> > -        return ret;
> > +        return;
> >      }
> > -
> > -    return ret;
> >  }
> >  
> >  static void spapr_irq_free_dual(SpaprMachineState *spapr, int irq)
> > @@ -622,12 +616,12 @@ void spapr_irq_init(SpaprMachineState *spapr, Error **errp)
> >                                        spapr->irq->nr_xirqs + SPAPR_XIRQ_BASE);
> >  }
> >  
> > -int spapr_irq_claim(SpaprMachineState *spapr, int irq, bool lsi, Error **errp)
> > +void spapr_irq_claim(SpaprMachineState *spapr, int irq, bool lsi, Error **errp)
> >  {
> >      assert(irq >= SPAPR_XIRQ_BASE);
> >      assert(irq < (spapr->irq->nr_xirqs + SPAPR_XIRQ_BASE));
> >  
> > -    return spapr->irq->claim(spapr, irq, lsi, errp);
> > +    spapr->irq->claim(spapr, irq, lsi, errp);
> >  }
> >  
> >  void spapr_irq_free(SpaprMachineState *spapr, int irq, int num)
> > diff --git a/include/hw/ppc/spapr_irq.h b/include/hw/ppc/spapr_irq.h
> > index ed88b4599a..75279ca137 100644
> > --- a/include/hw/ppc/spapr_irq.h
> > +++ b/include/hw/ppc/spapr_irq.h
> > @@ -42,7 +42,7 @@ typedef struct SpaprIrq {
> >      uint8_t     ov5;
> >  
> >      void (*init)(SpaprMachineState *spapr, Error **errp);
> > -    int (*claim)(SpaprMachineState *spapr, int irq, bool lsi, Error **errp);
> > +    void (*claim)(SpaprMachineState *spapr, int irq, bool lsi, Error **errp);
> >      void (*free)(SpaprMachineState *spapr, int irq);
> >      void (*print_info)(SpaprMachineState *spapr, Monitor *mon);
> >      void (*dt_populate)(SpaprMachineState *spapr, uint32_t nr_servers,
> > @@ -61,7 +61,7 @@ extern SpaprIrq spapr_irq_xive;
> >  extern SpaprIrq spapr_irq_dual;
> >  
> >  void spapr_irq_init(SpaprMachineState *spapr, Error **errp);
> > -int spapr_irq_claim(SpaprMachineState *spapr, int irq, bool lsi, Error **errp);
> > +void spapr_irq_claim(SpaprMachineState *spapr, int irq, bool lsi, Error **errp);
> >  void spapr_irq_free(SpaprMachineState *spapr, int irq, int num);
> >  qemu_irq spapr_qirq(SpaprMachineState *spapr, int irq);
> >  int spapr_irq_post_load(SpaprMachineState *spapr, int version_id);
> 

-- 
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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