Re: [PATCH 4/4] xen/char: pv_console: Fix MISRA C 2012 Rule 8.4 violation

[Xenia Ragiadakou <burzalodowa@xxxxxxxxx>]

On 7/6/22 10:18, Jan Beulich wrote:
> On 06.07.2022 00:02, Xenia Ragiadakou wrote:
> > Hi Julien,
> >
> > On 7/6/22 00:38, Julien Grall wrote:
> > > Hi Xenia,
> > >
> > > On 05/07/2022 22:02, Xenia Ragiadakou wrote:
> > > > The function pv_console_evtchn() is defined in the header
> > > > <xen/pv_console.h>.
> > > > If the header happens to be included by multiple files, this can
> > > > result in
> > > > linker errors due to multiple definitions,
> > > > So, it is more appropriate to resolve this MISRA C 2012 Rule 8.4
> > > > violation
> > > > warning by making pv_console_evtchn() inline with internal linkage.
> > > There are multiple version of pv_console_evtchn(). The version below is
> > > only used when !CONFIG_XEN_GUEST.
> > >
> > > The header is also included multiple time within Xen. So I am a bit
> > > puzzled why we haven't seen this error before. Maybe this is unused when
> > > !CONFIG_XEN_GUEST?
> > >
> > > If yes, I would remove the call. If no, then I think the commit message
> > > should be clarified.
> > You are right. I had to clarify that this holds when !CONFIG_XEN_GUEST.
> > So when !CONFIG_XEN_GUEST, the function pv_console_evtchn() is defined
> > inside the header file and the header is included only by a single file.
> > This is why the error has not been triggered.
> Irrespective of that it is as Julien suspects: The function is only ever
> referenced when XEN_GUEST. Hence the better course of action indeed looks
> to be to ditch the unused stub; we don't even need DCE here for there to
> not be any references.
Yes, if the function is not used at all when XEN_GUEST, then I think its 
definition is considered unreachable code (Rule 2.1) and needs to be 
removed.
--
Xenia