On Tue, 15 Sep 2020 13:58:53 +0300
Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> wrote:
14.09.2020 15:35, Greg Kurz wrote:
As recommended in "qapi/error.h", add a bool return value to
spapr_add_lmbs() and spapr_add_nvdimm(), and use them instead
of local_err in spapr_memory_plug().
Since object_property_get_uint() only returns 0 on failure, use
that as well.
Why are you sure? Can't the property be 0 itself?
Hmmm... I've based this assumption on the header:
* Returns: the value of the property, converted to an unsigned integer, or 0
* an error occurs (including when the property value is not an integer).
but looking at the implementation, I don't see any check that
a property cannot be 0 indeed...
It's a bit misleading to mention this in the header though. I
understand that the function should return something, which
should have a some explicitly assigned value to avoid compilers
or static analyzers to yell, but the written contract should be
that the value is _undefined_ IMHO.
In its present form, the only way to know if the property is
valid is to pass a non-NULL errp actually. I'd rather even see
that in the contract, and an assert() in the code.
An alternative would be to convert it to have a bool return
value and get the actual uint result with a pointer argument.
Also call ERRP_GUARD() to be able to check the status of void
function pc_dimm_plug() with *errp.
I'm now hesitating to either check *errp for object_property_get_uint()
too or simply drop this patch...