linux-kernel - Re: [PATCH 2/4] remoteproc: Split firmware name allocation from rproc

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Message-ID: <20200414194847.GF892431@yoga>
Date:   Tue, 14 Apr 2020 12:48:47 -0700
From:   Bjorn Andersson <bjorn.andersson@...aro.org>
To:     Mathieu Poirier <mathieu.poirier@...aro.org>
Cc:     Alex Elder <elder@...aro.org>, Ohad Ben-Cohen <ohad@...ery.com>,
        Suman Anna <s-anna@...com>,
        linux-remoteproc <linux-remoteproc@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 2/4] remoteproc: Split firmware name allocation from
 rproc_alloc()

On Tue 14 Apr 08:43 PDT 2020, Mathieu Poirier wrote:

> Hi guys,
> 
> On Mon, 13 Apr 2020 at 18:54, Bjorn Andersson
> <bjorn.andersson@...aro.org> wrote:
> >
> > On Mon 13 Apr 13:56 PDT 2020, Alex Elder wrote:
> >
> > > On 4/13/20 2:33 PM, Mathieu Poirier wrote:
> > > > Make the firmware name allocation a function on its own in order to
> > > > introduce more flexibility to function rproc_alloc().
> > > >
> > > > Signed-off-by: Mathieu Poirier <mathieu.poirier@...aro.org>
> > >
> > > I didn't look at the larger context (MCU series); I'm only looking
> > > at this (and the others in this series) in isolation.  I like
> > > that you're encapsulating this stuff into functions but doing so
> > > doesn't really add any flexibility.
> > >
> > > Two small suggestions for you to consider but they're truly
> > > more about style so it's entirely up to you.  Outside of that
> > > this looks straightforward to me, and the result of the series
> > > is an improvement.
> > >
> > > I'll let you comment on my suggestions before offering my
> > > "reviewed-by" indication.
> > >
> > >                                       -Alex
> > >
> > > > ---
> > > >  drivers/remoteproc/remoteproc_core.c | 66 ++++++++++++++++------------
> > > >  1 file changed, 39 insertions(+), 27 deletions(-)
> > > >
> > > > diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c
> > > > index 80056513ae71..4dee63f319ba 100644
> > > > --- a/drivers/remoteproc/remoteproc_core.c
> > > > +++ b/drivers/remoteproc/remoteproc_core.c
> > > > @@ -1979,6 +1979,33 @@ static const struct device_type rproc_type = {
> > > >     .release        = rproc_type_release,
> > > >  };
> > > >
> > > > +static int rproc_alloc_firmware(struct rproc *rproc,
> > > > +                           const char *name, const char *firmware)
> > > > +{
> > > > +   char *p, *template = "rproc-%s-fw";
> > > > +   int name_len;
> > >
> > > Not a big deal (and maybe it's not consistent with other nearby
> > > style) but template and name_len could be defined inside the
> > > "if (!firmware)" block.
> > >
> >
> > I prefer variables declared in the beginning of the function, so I'm
> > happy with this.
> >
> > > > +   if (!firmware) {
> > > > +           /*
> > > > +            * If the caller didn't pass in a firmware name then
> > > > +            * construct a default name.
> > > > +            */
> > > > +           name_len = strlen(name) + strlen(template) - 2 + 1;
> > > > +           p = kmalloc(name_len, GFP_KERNEL);
> > >
> > >
> > > I don't know if it would be an improvement, but you could
> > > check for a null p value below for both cases.  I.e.:
> > >
> > >               if (p)
> > >                       snprintf(p, ...);
> > >
> >
> > Moving the common NULL check and return out seems nice, but given that
> > we then have to have this positive conditional I think the end result is
> > more complex.
> >
> > That said, if we're not just doing a verbatim copy from rproc_alloc() I
> > think we should make this function:
> >
> >         if (!firmware)
> >                 p = kasprintf(GFP_KERNEL, "rproc-%s-fw", name);
> >         else
> >                 p = kstrdup_const(firmware, GFP_KERNEL);
> >
> >         rproc->firmware = p;
> >
> >         return p ? 0 : -ENOMEM;
> 
> At this time I was going for a pure re-arrangement of the code and
> avoiding further improvement.  This is simple enough that it can be
> rolled-in the next revision.
> 

The resulting patch would be "factor out AND rewrite", which generally
is good cause for splitting things in two patches...

Regards,
Bjorn