Re: [Qemu-devel] [PATCH 03/10] pseries: Clean up hash page table allocation error handling

[Alexey Kardashevskiy]

On 01/18/2016 04:35 PM, David Gibson wrote:
> On Mon, Jan 18, 2016 at 04:17:08PM +1100, Alexey Kardashevskiy wrote:
> > On 01/18/2016 03:42 PM, David Gibson wrote:
> > > On Mon, Jan 18, 2016 at 01:44:00PM +1100, Alexey Kardashevskiy wrote:
> > > > On 01/15/2016 11:00 PM, David Gibson wrote:
> > > > > The spapr_alloc_htab() and spapr_reset_htab() functions currently handle
> > > > > all errors with error_setg(&error_abort, ...).
> > > > >
> > > > > But really, the callers are really better placed to decide on the error
> > > > > handling.  So, instead make the functions use the error propagation
> > > > > infrastructure.
> > > > >
> > > > > In the callers we change to &error_fatal instead of &error_abort, since
> > > > > this can be triggered by a bad configuration or kernel error rather than
> > > > > indicating a programming error in qemu.
> > > > >
> > > > > While we're at it improve the messages themselves a bit, and clean up the
> > > > > indentation a little.
> > > > >
> > > > > Signed-off-by: David Gibson <address@hidden>
> > > > > ---
> > > > >   hw/ppc/spapr.c | 24 ++++++++++++++++--------
> > > > >   1 file changed, 16 insertions(+), 8 deletions(-)
> > > > >
> > > > > diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> > > > > index b7fd09a..d28e349 100644
> > > > > --- a/hw/ppc/spapr.c
> > > > > +++ b/hw/ppc/spapr.c
> > > > > @@ -1016,7 +1016,7 @@ 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;
> > > > > @@ -1031,7 +1031,8 @@ 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_errno(errp, -shift,
> > > > > +                         "Error allocating KVM hash page table, try smaller 
> > > > > maxmem");
> > > > >       } else if (shift > 0) {
> > > > >           /*
> > > > >            * Kernel handles htab, we don't need to allocate one
> > > > > @@ -1040,7 +1041,10 @@ static void spapr_alloc_htab(sPAPRMachineState *spapr)
> > > > >            * but we don't allow booting of such guests.
> > > > >            */
> > > > >           if (shift != spapr->htab_shift) {
> > > > > -            error_setg(&error_abort, "Failed to allocate HTAB of requested size, 
> > > > > try with smaller maxmem");
> > > > > +            error_setg(errp,
> > > > > +                "Small allocation for KVM hash page table (%ld < %"
> > > > > +                PRIu32 "), try smaller maxmem",
> > > >
> > > >
> > > >
> > > > Even though it is not in the CODING_STYLE, I have not seen anyone objecting
> > > > the very good kernel's "never break user-visible strings" rule or rejecting
> > > > patches with user-visible strings failing to fit 80 chars limit.
> > >
> > > I'm not.  Or rather, the string is already broken by the PRIu32, so
> > > the newline doesn't make it any less greppable.
> >
> >
> > "KVM hash page table.*smaller maxmem" stopped working. Not a big deal but I
> > do not see any win in breaking strings anyway.
>
> The problem is that the current pre-commit hooks don't agree with
> you.  They seem to allow long unbroken strings, but if there's a break
> like the PRIu32, they won't permit the commit.


checkpatch.pl reports it as "WARNING: line over 80 characters", not an 
ERROR, so I'd say the hook has a problem.



--
Alexey