Re: [Qemu-devel] [PATCH v4 RFC] block/vxhs: Initial commit to add Veritas HyperScale VxHS block device support

[Kevin Wolf]

Am 08.09.2016 um 11:43 hat Daniel P. Berrange geschrieben:
> On Thu, Sep 08, 2016 at 11:29:41AM +0200, Kevin Wolf wrote:
> > Am 08.09.2016 um 10:49 hat Daniel P. Berrange geschrieben:
> > > On Thu, Sep 08, 2016 at 10:43:19AM +0200, Kevin Wolf wrote:
> > > > Am 08.09.2016 um 00:32 hat ashish mittal geschrieben:
> > > > > >> +
> > > > > >> +void vxhs_set_acb_buffer(void *ptr, void *buffer)
> > > > > >> +{
> > > > > >> +    VXHSAIOCB *acb = ptr;
> > > > > >> +
> > > > > >> +    acb->buffer = buffer;
> > > > > >> +}
> > > > > >> +
> > > > > >
> > > > > > Unused function?
> > > > > 
> > > > > This is called from within libqnio.
> > > > 
> > > > Wait, you mean the library references a symbol in the qemu binary? This
> > > > sounds completely wrong to me. I wouldn't even do something like this if
> > > > it were an internal qemu library because I think libraries should be
> > > > self-contained, but it's a much larger problem in something that is
> > > > supposed to be an independent library.
> > > 
> > > I'd be surprised if that actually worked. If an external library wants
> > > to refrence symbols in the QEMU binary, then QEMU would ned to be using
> > > the -export-dynamic / -rdynamic linker flags to export all its symbols,
> > > and AFAIK, we're not doing that.
> > 
> > Hm, but if the function is really used by the library, how else would it
> > be when its name isn't mentioned anywhere in the patch except in its
> > declaration? And it appears to be called there directly:
> > 
> > https://github.com/MittalAshish/libqnio/search?q=vxhs_set_acb_buffer
> > 
> > Anyway, something is fishy here.
> 
> Oh, notice that .c file is actually part of the shim library, not the
> main libqnio.so that QEMU would link against.
> 
> So, it really is unused and should be deleted from this block/vxhs.c
> file.

I haven't fully understood yet what's the deal with this shim library,
but this patch links against both.

Kevin