Re: [PATCH 26/44] kdbus: Cleanup kdbus_pin_dst()

[Sergei Zviagintsev]

Hi,

On Thu, Oct 08, 2015 at 04:40:33PM +0200, David Herrmann wrote:
> Hi
> 
> On Thu, Oct 8, 2015 at 1:31 PM, Sergei Zviagintsev <sergei@xxxxxxxx> wrote:
> >  - Reduce scope of `owner' var to the block where it is actually used.
> >    Use conditional operator to set its value.
> >
> >  - Drop initialization of `dst' as it gets value later.
> >
> >  - Drop separate exit point as we have only one use case of it.
> >
> > Signed-off-by: Sergei Zviagintsev <sergei@xxxxxxxx>
> > ---
> >  ipc/kdbus/connection.c | 17 ++++++-----------
> >  1 file changed, 6 insertions(+), 11 deletions(-)
> >
> > diff --git a/ipc/kdbus/connection.c b/ipc/kdbus/connection.c
> > index 6a73ac3f444d..ace587ee951a 100644
> > --- a/ipc/kdbus/connection.c
> > +++ b/ipc/kdbus/connection.c
> > @@ -1048,10 +1048,8 @@ static int kdbus_pin_dst(struct kdbus_bus *bus,
> >                          struct kdbus_conn **out_dst)
> >  {
> >         const struct kdbus_msg *msg = staging->msg;
> > -       struct kdbus_name_owner *owner = NULL;
> >         struct kdbus_name_entry *name = NULL;
> > -       struct kdbus_conn *dst = NULL;
> > -       int ret;
> > +       struct kdbus_conn *dst;
> >
> >         lockdep_assert_held(&bus->name_registry->rwlock);
> >
> > @@ -1061,14 +1059,15 @@ static int kdbus_pin_dst(struct kdbus_bus *bus,
> >                         return -ENXIO;
> >
> >                 if (!kdbus_conn_is_ordinary(dst)) {
> > -                       ret = -ENXIO;
> > -                       goto error;
> > +                       kdbus_conn_unref(dst);
> > +                       return -ENXIO;
> 
> Looks good.
> 
> >                 }
> >         } else {
> > +               struct kdbus_name_owner *owner;
> > +
> 
> I'd prefer if you avoid making this block-local.

What is the rule of keeping (or not) things block-local? I always
thought the less vars we keep in the mind at time, the easier is a
piece of code to read.

> 
> >                 name = kdbus_name_lookup_unlocked(bus->name_registry,
> >                                                   staging->dst_name);
> > -               if (name)
> > -                       owner = kdbus_name_get_owner(name);
> > +               owner = name ? kdbus_name_get_owner(name) : NULL;
> 
> Looks good.
> 
> >                 if (!owner)
> >                         return -ESRCH;
> >
> > @@ -1094,10 +1093,6 @@ static int kdbus_pin_dst(struct kdbus_bus *bus,
> >         *out_name = name;
> >         *out_dst = dst;
> >         return 0;
> > -
> > -error:
> > -       kdbus_conn_unref(dst);
> > -       return ret;
> 
> Looks good.
> 
> Thanks
> David
> 
> >  }
> >
> >  static int kdbus_conn_reply(struct kdbus_conn *src,
> > --
> > 1.8.3.1
> >
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