Re: kernel-doc : possible fix for non-fatal perl errors whenparsing some function pointers

From: Randy Dunlap
Date: Fri Feb 15 2008 - 12:53:30 EST


On Fri, 15 Feb 2008 09:44:37 -0800 Randy Dunlap wrote:

> On Fri, 15 Feb 2008 09:21:54 -0800 Randy Dunlap wrote:
>
> > On Fri, 15 Feb 2008 17:13:12 +0000 Richard Kennedy wrote:
> >
> > > When running "make htmldocs" I'm seeing some non-fatal perl errors
> > > caused by trying to parse the callback function definitions in
> > > blk-core.c.
> > >
> > > The errors are "Use of uninitialized value in concatenation (.)..."
> > >
> > > The function pointers are defined without a * i.e.
> > > int (drv_callback)(struct request *)
> > >
> > > The compiler is happy with them, but kernel-doc isn't.
> > >
> > > This patch teaches create_parameterlist in kernel-doc to parse this type
> > > of function pointer definition, but is it the right way to fix the
> > > problem ? The problem only seems to occur in blk-core.c.
> > >
> > > However with the patch applied, kernel-doc finds the correct parameter
> > > description for the callback in blk_end_request_callback, which is
> > > doesn't normally.
> > > (the patch is against v2.6.25-rc1)
> > >
> > > I thought it would be a bit odd to change to code to use the more normal
> > > form of function pointers just to get the documentation to work, so I
> > > fixed kernel-doc instead - even though this is teaching it to understand
> > > code that might go away (The comment for blk_end_request_callback says
> > > that it should not be used and will removed at some point).
> > >
> > > Any ideas on which is the best way to fix this?
> >
> > Hi Richard,
> > Thanks for the patch. I was planning to look into this problem
> > this weekend.
> >
> > I think that changing scripts/kernel-doc to accept the current
> > kernel source tree usage is the right thing to do, even if the
> > block/blk code is a bit different. I'll test it a bit and then
> > push it.
>
> I'm not quite happy with the way that these function pointer
> parameters are presented. E.g.,
> the callback function above is presented by kernel-doc as:
>
> int ()(struct request *) drv_callback);
> whereas this
> int (drv_callback)(struct request *)
> would be much better. If you could look into massaging that
> parameter output, that would be great. If not, I'll look into
> later.

OK, this is a separate issue, so your patch doesn't need to handle/fix
it. I'll check your followup email/patch for whitespace etc....


> > I appreciate the patch.
> >
> > > diff --git a/scripts/kernel-doc b/scripts/kernel-doc
> > > index 26146cb..68b2e4e 100755
> > > --- a/scripts/kernel-doc
> > > +++ b/scripts/kernel-doc
> > > @@ -1512,13 +1512,13 @@ sub create_parameterlist($$$) {
> > > # corresponding data structures "correctly". Catch it later in
> > > # output_* subs.
> > > push_parameter($arg, "", $file);
> > > - } elsif ($arg =~ m/\(.*\*/) {
> > > + } elsif ($arg =~ m/\(.+\)\s*\(/) {
> > > # pointer-to-function
> > > $arg =~ tr/#/,/;
> > > - $arg =~ m/[^\(]+\(\*\s*([^\)]+)\)/;
> > > + $arg =~ m/[^\(]+\(\*?\s*(\w*)\s*\)/;
> > > $param = $1;
> > > $type = $arg;
> > > - $type =~ s/([^\(]+\(\*)$param/$1/;
> > > + $type =~ s/([^\(]+\(\*?)$param/$1/;
> > > push_parameter($param, $type, $file);
> > > } elsif ($arg) {
> > > $arg =~ s/\s*:\s*/:/g;

---
~Randy
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/