Re: [libvirt] PATCH: 12/28: Thread safety for UML driver

[Daniel Veillard <veillard redhat com>]

On Tue, Dec 02, 2008 at 11:06:38AM +0000, Daniel P. Berrange wrote:
> On Tue, Dec 02, 2008 at 12:05:10PM +0100, Daniel Veillard wrote:
> > On Sun, Nov 30, 2008 at 11:53:17PM +0000, Daniel P. Berrange wrote:
> > > This patch makes the UML driver thread safe
> > 
> > [...]
> > > @@ -1395,21 +1485,27 @@ static int umlListDefinedDomains(virConn
> > >      struct uml_driver *driver = conn->privateData;
> > >      int got = 0, i;
> > >  
> > > +    umlDriverLock(driver);
> > >      for (i = 0 ; i < driver->domains.count && got < nnames ; i++) {
> > > +        virDomainObjLock(driver->domains.objs[i]);
> > >          if (!virDomainIsActive(driver->domains.objs[i])) {
> > >              if (!(names[got++] = strdup(driver->domains.objs[i]->def->name))) {
> > >                  umlReportError(conn, NULL, NULL, VIR_ERR_NO_MEMORY,
> > >                                   "%s", _("failed to allocate space for VM name string"));
> > > +                virDomainObjUnlock(driver->domains.objs[i]);
> > >                  goto cleanup;
> > >              }
> > >          }
> > > +        virDomainObjUnlock(driver->domains.objs[i]);
> > >      }
> > > +    umlDriverUnlock(driver);
> > >  
> > >      return got;
> > >  
> > >   cleanup:
> > 
> >   since this is an error code path, I would rather change the label to
> > error: ...
> 
> That's a good idea - we should define a standard naming for this usage
> 
>   'cleanup' to be used where error & normal conditions shared the same
>             exit path of a method.
> 
>   'error' to be used where error path is completely separate from the
>           normal exit path.

  yup since we're going to have labels on a lot of functions for exit we
should try to standardize their use and name. The set of patches does
this mostly, just a small incremental improvement, and then we can
document it in the HACKING file.

Daniel

-- 
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