Re: [PATCH 1/1 linux-next] fs/coda/upcall.c: remove UPARG flow control macro

From: Fabian Frederick
Date: Mon Apr 27 2015 - 15:44:37 EST




> On 27 April 2015 at 20:37 Jan Harkes <jaharkes@xxxxxxxxxx> wrote:
>
>
> On Mon, Apr 27, 2015 at 07:23:06PM +0200, Fabian Frederick wrote:
> > Move UPARG code to alloc_upcall() and test errors/return in callsites.
> > This patch removes flow control in macros which must be avoided.
> > (See Documentation/CodingStyle)
>
> At first glance this is not a correct patch.
>
> UPARG allocates a buffer that is large enough to hold both the upcall
> message going to userspace as well as the incoming reply message. At
> first glance this patch only seems to allocate insize. It may still be
> doing the right thing because insize is defined at the call level as
> MAX(sizeof(inarg), sizeof(outarg)). This it looks like quite a few
> changes for an untested patch and not enough for an actual cleanup of
> the related code.
>
> Jan

Sorry Jan but I don't see any problem in that patch.
outarg is processed the same way:

New alloc_upcall(**inp, **outp):
*outp = (union outputArgs *)inp;
*outsize = insize;

UPARG macro:
outp = (union outputArgs *)(inp); \
outsize = insize; \

Regards,
Fabian


>
> > ---
> > This is untested.
> >
> >Â fs/coda/upcall.c | 107
> >+++++++++++++++++++++++++++++++++++--------------------
> >Â 1 file changed, 69 insertions(+), 38 deletions(-)
> >
> > diff --git a/fs/coda/upcall.c b/fs/coda/upcall.c
> > index 9b1ffaa..7524f630 100644
> > --- a/fs/coda/upcall.c
> > +++ b/fs/coda/upcall.c
> > @@ -41,30 +41,24 @@
> >Â static int coda_upcall(struct venus_comm *vc, int inSize, int *outSize,
> >Â Â Â Â Â Â Â Â Â Â union inputArgs *buffer);
>
> > -static void *alloc_upcall(int opcode, int size)
> > +static int alloc_upcall(int opcode, int insize, int *outsize,
> > +Â Â Â Â Â Â Â Â Â Âunion inputArgs **inp, union outputArgs **outp)
> >Â {
> > -Â Âunion inputArgs *inp;
> > +Â ÂCODA_ALLOC(*inp, union inputArgs *, insize);
> > +Â Âif (!*inp)
> > +Â Â Â Â Â Âreturn -ENOMEM;
>
> > -Â ÂCODA_ALLOC(inp, union inputArgs *, size);
> > -Â Â Â Â if (!inp)
> > -Â Â Â Â Â Âreturn ERR_PTR(-ENOMEM);
> ...
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