[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [PATCH v2 for-5.0 0/8] ppc: Consolidate QOM links and pointers to th
From: |
Greg Kurz |
Subject: |
Re: [PATCH v2 for-5.0 0/8] ppc: Consolidate QOM links and pointers to the same object |
Date: |
Mon, 18 Nov 2019 12:01:28 +0100 |
On Mon, 18 Nov 2019 10:26:12 +0100
Markus Armbruster <address@hidden> wrote:
> Greg Kurz <address@hidden> writes:
>
> > There's a recurring pattern in the code where a const link is added to a
> > newly instanciated object and the link is then used in the object's realize
> > function to keep a pointer to the QOM entity which the link points to.
> >
> > void create_obj_b(Object *obj_a)
> > {
> > Object *obj_b;
> >
> > obj_b = object_new(TYPE_B);
> > object_property_add_const_link(obj_b, "link-to-a", obj_a, &error_abort);
> > object_property_set_bool(obj_b, true, "realized", &error_abort);
> > }
> >
> > void object_b_realize(DeviceState *dev, Error **errp)
> > {
> > Object *obj_a;
> >
> > obj_a = object_property_get_link(OBJECT(dev), "link-to-a", errp);
> > if (!obj_a) {
> > return;
> > }
> >
> > obj_b->obj_a = A(obj_a); // If obj_b->obj_a is changed, the link
> > property
> > // still points to the original obj_a that was
> > // passed to object_property_add_const_link()
> > }
> >
> > Confusing bugs could arise if the pointer and the link go out of sync for
> > some reason. This can be avoided if the property is defined to directly use
> > the pointer with the DEFINE_PROP_LINK() macro.
> >
> > This series just does that for all occurences of the fragile pattern in
> > the XIVE and PNV code.
>
> Have you looked for the pattern elsewhere?
>
No I was focusing on the XICS/XIVE interrupt controller code for PPC machines
only. I'll have a broader look.
- [PATCH v2 for-5.0 2/8] xive: Link "xive" property to XiveSource::xive pointer, (continued)
- [PATCH v2 for-5.0 2/8] xive: Link "xive" property to XiveSource::xive pointer, Greg Kurz, 2019/11/15
- [PATCH v2 for-5.0 3/8] xive: Link "xive" property to XiveEndSource::xrtr pointer, Greg Kurz, 2019/11/15
- [PATCH v2 for-5.0 4/8] ppc/pnv: Link "psi" property to PnvLpc::psi pointer, Greg Kurz, 2019/11/15
- [PATCH v2 for-5.0 5/8] ppc/pnv: Link "psi" property to PnvOCC::psi pointer, Greg Kurz, 2019/11/15
- [PATCH v2 for-5.0 6/8] ppc/pnv: Link "chip" property to PnvHomer::chip pointer, Greg Kurz, 2019/11/15
- [PATCH v2 for-5.0 7/8] ppc/pnv: Link "chip" property to PnvCore::chip pointer, Greg Kurz, 2019/11/15
- [PATCH v2 for-5.0 8/8] ppc/pnv: Link "chip" property to PnvXive::chip pointer, Greg Kurz, 2019/11/15
- Re: [PATCH v2 for-5.0 0/8] ppc: Consolidate QOM links and pointers to the same object, David Gibson, 2019/11/15
- Re: [PATCH v2 for-5.0 0/8] ppc: Consolidate QOM links and pointers to the same object, Markus Armbruster, 2019/11/18