On Mon, 10 Feb 2014 18:00:39 +0100
Laszlo Ersek <ler...@redhat.com> wrote:
> comments below
>
> On 02/06/14 09:16, Igor Mammedov wrote:
> > From: Paolo Bonzini <pbonz...@redhat.com>
> >
> > Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>
> > Signed-off-by: Igor Mammedov <imamm...@redhat.com>
> > ---
> > include/qemu/config-file.h | 2 ++
> > util/qemu-config.c | 14 ++++++++++++++
> > vl.c | 11 +----------
> > 3 files changed, 17 insertions(+), 10 deletions(-)
> >
> > diff --git a/include/qemu/config-file.h b/include/qemu/config-file.h
> > index dbd97c4..d4ba20e 100644
> > --- a/include/qemu/config-file.h
> > +++ b/include/qemu/config-file.h
> > @@ -8,6 +8,8 @@
> >
> > QemuOptsList *qemu_find_opts(const char *group);
> > QemuOptsList *qemu_find_opts_err(const char *group, Error **errp);
> > +QemuOpts *qemu_find_opts_singleton(const char *group);
> > +
> > void qemu_add_opts(QemuOptsList *list);
> > void qemu_add_drive_opts(QemuOptsList *list);
> > int qemu_set_option(const char *str);
> > diff --git a/util/qemu-config.c b/util/qemu-config.c
> > index 9298f55..9dfacbc 100644
> > --- a/util/qemu-config.c
> > +++ b/util/qemu-config.c
> > @@ -39,6 +39,20 @@ QemuOptsList *qemu_find_opts(const char *group)
> > return ret;
> > }
> >
> > +QemuOpts *qemu_find_opts_singleton(const char *group)
> > +{
> > + QemuOptsList *list;
> > + QemuOpts *opts;
> > +
> > + list = qemu_find_opts(group);
> > + assert(list);
> > + opts = qemu_opts_find(list, NULL);
> > + if (!opts) {
> > + opts = qemu_opts_create(list, NULL, 0, &error_abort);
> > + }
> > + return opts;
> > +}
>
> First of all, the commit message body is empty, and the subject line
> doesn't really say much, plus there are no comments, so I have no clue
> what we're trying to implement here *in general*.
>
> For example, if you look into qemu_opts_create(), you'll see that when
> (id==NULL), then you don't actually need the
>
> qemu_opts_find(list, NULL)
>
> call, because qemu_opts_create() calls that itself anyway. Of course,
> this behavior *also* depends on merge_lists being "true", but in case of
> "machine", that *is* a given.
>
> Hence a specification for the function would help deciding if we can
> take merge_lists for granted, or if we want something more general. In
> the former case, the code above is unnecessarily pessimistic.
>
> (Basically the qemu_find_opts_singleton() should be a *very* thin
> wrapper around qemu_opts_create(), because the latter already has this
> "O_CREAT without O_EXCL" semantics.)
I'd guess function qemu_find_opts_singleton() is called so to express
common idiom and shouldn't have an expectation for merge_lists == true
being granted. So it could be reused with other options as well.
>
> > +
> > static CommandLineParameterInfoList *query_option_descs(const QemuOptDesc
> > *desc)
> > {
> > CommandLineParameterInfoList *param_list = NULL, *entry;
> > diff --git a/vl.c b/vl.c
> > index 383be1b..7f2595c 100644
> > --- a/vl.c
> > +++ b/vl.c
> > @@ -539,16 +539,7 @@ static QemuOptsList qemu_msg_opts = {
> > */
> > QemuOpts *qemu_get_machine_opts(void)
> > {
> > - QemuOptsList *list;
> > - QemuOpts *opts;
> > -
> > - list = qemu_find_opts("machine");
> > - assert(list);
> > - opts = qemu_opts_find(list, NULL);
> > - if (!opts) {
> > - opts = qemu_opts_create(list, NULL, 0, &error_abort);
> > - }
> > - return opts;
> > + return qemu_find_opts_singleton("machine");
> > }
> >
> > const char *qemu_get_vm_name(void)
> >
>
> I also kinda hate that "error_abort" -- while used in several
> option-specific parser functions (balloon_parse, virtcon_parse,
> QEMU_OPTION_virtfs, QEMU_OPTION_virtfs_synth) -- now makes it into a
> generic-looking options function. qemu_find_opts_singleton() should take
> an errp.
looking at possible call paths qemu_opts_create() with given arguments should
never fail so assert like behavior here seems to be just fine, so we would
notice for certain if/when it breaks.
>
> Anyway I don't care enough to insist on a respin.
>
> Reviewed-by: Laszlo Ersek <ler...@redhat.com>
>
